"Sleeping in the Sky and in Space" Erin E Flynn-Evans (01.20.2021)

January 24, 2021

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To CiteDCA Citation Guide

00:21Alright, I think we'll get started.
00:23Hello everyone, my name is Lauren
00:25Tobias and I'd like you to,
00:27well would like to welcome everyone
00:29to wear Yale Sleep seminar this
00:30afternoon before we get started.
00:32I have a few brief announcements.
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00:52And today, specifically,
00:53I'm hearing that the CME Office
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01:13as well as on our announcement email.
01:15If you have any questions during
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01:47So now I am really delighted
01:50to introduce today's speaker,
01:51Doctor Aaron Flynn Evans.
01:52Dr Flynn Evans is a research
01:54psychologist at the NASA Ames
01:56Research Center in California.
01:58Where she is director of the
02:00Fatigue Countermeasures Laboratory.
02:01She received her PhD from the
02:04University of Siri in the UK an her
02:06Masters in Public Health from the
02:08Harvard School of Public Health.
02:11She was also certified as an RP Sgt
02:14from 2002 to 2012 and Prior to joining NASA.
02:17She was an instructor of medicine
02:19in the Division of Sleep Medicine
02:21at Brigham and Women's Hospital
02:23and Harvard Medical School.
02:25Doctor Flynn Evans has extensive
02:27research experience and examining
02:28the short and long term.
02:30Effects of sleep loss and circadian
02:33desynchrony in occupational
02:34settings including among astronauts,
02:36airline pilots, physicians,
02:38and other shift workers.
02:39She is involved in both laboratory
02:42and field based research.
02:44Her laboratory based research has
02:46focused on the effects of light
02:49on circadian neuroendocrine and
02:51neurobehavioural responses in humans
02:54and how these might relate to the
02:57development of countermeasures
02:58for shift work.
03:00Her field research has integrated these
03:02measures of fatigue and countermeasure
03:04of fatigue countermeasures into
03:06complex occupational settings.
03:08She's very active with the American
03:10Academy of Sleep Medicine and
03:13the Sleep Research Society.
03:14She's served as a member of their
03:18Public Safety Committee as well
03:20as on the shift work duration,
03:22consensus committee,
03:23and although we may not regularly
03:25encounter patients who
03:27are pilots or astronauts in our
03:29own practices, Doctor Flynn Evans.
03:31Work on circadian disruption,
03:33an fatigue mitigation in these
03:35populations has important
03:36application to our own patients,
03:38so I'm really excited for her
03:40talk and with that I'll turn
03:42it over to Doctor Flynn Evans.
03:47Awesome, thank you. Thank you
03:50so much Lord for inviting me.
03:52I'm very excited to be here and
03:55thank you all for attending,
03:57especially after the inauguration.
03:59I didn't realize until after I picked
04:03the date when Lauren reminded me
04:05that today was an operation day.
04:07So again, thank you for taking the
04:10time after after the inauguration.
04:13To hear this talk. So to begin,
04:16I just like to give you a little.
04:20Primer on NASA,
04:21and I think you know you may have
04:24seen the advertisement for this talk
04:26and thought why someone from NASA
04:29coming to talk to us about sleep.
04:32But as you heard,
04:33I have a long background in Sleep
04:36Medicine and circadian Physiology.
04:38Also in Epidemiology,
04:40and I was recruited to come to NASA.
04:44Several years ago,
04:46after working on some grants.
04:50At Harvard,
04:51where we were studying sleep in
04:54space and NASA has a long history
04:57of doing fatigue risk management
05:00in aviation and in spaceflight,
05:02and Mark Rosekind,
05:04who some of you may know who
05:07was an NTSB board member.
05:10And then during the Obama
05:12administration was the National
05:14Highway Transportation Authority lead,
05:16which is a presidential appointment
05:19he founded the lab at NASA Ames.
05:22And really established the you know
05:25sort of fatigue, risk management,
05:27best practices for aviation.
05:29So after he left there were a few
05:32different iterations of the lab,
05:34but really it kind of went dormant for
05:38many years and after we were doing work.
05:42On Space Flight, when I was in Boston,
05:45there was interest.
05:46Renewed interest in asset to,
05:48you know, really redeveloped the lab.
05:50And so I was very honored and
05:52excited to be able to take over
05:55and then rebuild and forge a new
05:57path forward for what fatigue
05:59risk management means at NASA.
06:01So what we have here are 10 NASA centers,
06:04so you may not realize that there are 10.
06:07But you can see we have Houston,
06:10in which I'm sure you all know
06:13that in Kennedy.
06:14You have lunches, but we also have.
06:18Spaceflight focused centers with Mission
06:20Control and a rocket building center.
06:22Here we have NASA Langley, Goddard,
06:25NASA, Glenn, and then we have,
06:27of course JPL in Southern California,
06:30NASA, Armstrong,
06:30and then I'm right up here in the
06:33Bay Area at NASA Ames Research
06:36Center and our center acts must
06:38much like an academic campus.
06:41It's really entirely research.
06:42Research is in the name of our center,
06:46and we do a lot of the.
06:48The foundational support for
06:50all of the other centers.
06:52So we're doing research not just on humans,
06:54but there's a lot of molecular
06:57biology that happens at NASA Ames.
06:59And then there's also material
07:01scientists who were doing things
07:03like testing the heat Shields that.
07:05Will help protect vehicles when they
07:07re enter the atmosphere from space.
07:10And here's a picture of our campus
07:12so I would say the biggest defining
07:15feature here is this giant wind tunnel.
07:18It's the world's largest wind tunnel,
07:20can fit a very large airplane
07:22inside it and my lab is right
07:25back here you can see the San
07:27Francisco Bay in the background and for
07:30reference we're about 6 miles from Stanford
07:33and so that I have become the adopted.
07:36Childhood Stanford since moving to
07:38California because I'm the only the sleep
07:41lab Sleep Research group at NASA Ames and
07:43so to get sort of my intellectual fix,
07:45I spend a lot of time over at
07:47Stanford attending their sleep grounds
07:49and participating in activities
07:50that they have going on.
07:52So it's very convenient to be
07:54in such a rich environment.
07:55And then of course,
07:57we're in the middle of Silicon Valley,
07:59so we have a lot of exciting
08:02tech happening too.
08:03In terms of what we do in
08:05my lab in particular,
08:06I mentioned that we do spaceflight work,
08:08which we'd expect for NASA,
08:10but the you know NASA is the National
08:12Aeronautics and Space Administration,
08:13and so you know the first day is aeronautics,
08:16so we do a lot of work in aviation as well.
08:19And in my lap we do about a third
08:21of our research work in aviation.
08:24And then we also have a sleep
08:26lab where we do more.
08:28Controlled experiments evaluating the
08:31effectiveness of different countermeasures.
08:35And I think that it's like a playground
08:37where we can test new solutions,
08:40new tech and then once we
08:42have embedded in the lab,
08:44we can take them back out into
08:46the field and see if they work to
08:49help mitigate fatigue or improve
08:50performance or improve sleep.
08:52Depending on the need.
08:56Today I'm going to take you through
08:58really just two of these areas,
09:00so I'll briefly touch on her laboratory work,
09:03but I think the really interesting
09:05stuff that we do is in the field,
09:08so I'm going to take you through
09:10a couple of studies that we've
09:12done in aviation to help you get
09:15a sense of how we are assessing by
09:18pilot alertness and performance,
09:19and sleep in the field.
09:21I'll take you through a countermeasure
09:23study that we did with airline pilots.
09:26And then we'll switch gears and talk
09:28about spaceflight and here talk about really.
09:31Specifically a study that we did that I
09:34started when I was in Boston at Harvard
09:36looking at sleep duration in space
09:39at as well as circadian misalignment.
09:41And then I'm just going to give
09:44you a little taste of some of the
09:47other types of studies that we
09:49do is really difficult to pick.
09:52What studies to focus on?
09:54Because I I find everything that we do
09:57interesting, and so if you have a party.
10:00Ocular interest in something that
10:02I'm not talking about in depth.
10:03Feel free to reach out and then happy.
10:06Happy, happy to discuss.
10:08So firstly,
10:09when I came to NASA,
10:11one of the biggest challenges
10:13that I faced was just how do you
10:16do field data collection.
10:17So when I was in Boston I was part
10:20of the Harvard work hours health
10:23and Safety Group and we did a
10:26lot of occupational work looking
10:28at work hours and different.
10:30You know in medicine looking
10:32at resident work
10:33hours in firefighters and police.
10:35So we I had some experience.
10:38Assessing alertness and performance
10:39and sleep in the field,
10:41but we we didn't really do in
10:44those studies we had like dedicated
10:46control centers in hospital where
10:49we could have residents come in
10:51and do tests and have more sort
10:54of laboratory based assessments.
10:55And when we're talking about
10:57airline pilots or astronauts,
10:59we don't really have the ability to
11:02engage with them on a day-to-day basis.
11:05Basically, we have to give them
11:07all the tools that they need to.
11:10Participate in a study,
11:11send them on their way,
11:12and then hope for the best.
11:14And so I wanted to make sure that the
11:17measures that we were using would really.
11:19Um, give us the type of the high
11:22quality data that we collected that
11:24we get from a laboratory study.
11:26And also you know what would
11:28be meaningful and easy to use.
11:30And so the first thing that I did was
11:32start to explore different options.
11:35So of course we know that self
11:37report measures are simple,
11:38but you know if you have somebody who's
11:41motivated to say that they're doing fine,
11:43particularly when we talk
11:45about our astronaut community,
11:46you know they may say, I'm alert,
11:48alert, alert.
11:49When you know that they're probably
11:52feeling the effects of sleepiness
11:53and then we have cognitive tests
11:56which I have the Pvt 192 here.
11:58I'm not sure how many of you
12:00are familiar with the PT.
12:02192, but this psycho motor vigilance task,
12:04so simple reaction time tests that you've
12:06probably read about in many many papers.
12:09Probably even use yourself for studies,
12:11but the original Pvt when I need
12:13to is something that we actually
12:15have in NASA Ames and it's giant
12:17response box that's really unwieldy.
12:19And you can use it and allow,
12:21but there's no way you're going to deploy
12:24this giant response box out into the field.
12:27Ann,
12:28and so you know that is sort of sort of
12:31challenging to think about how we might
12:33collect performance data in the field.
12:35And then there was a push
12:37for real world measures.
12:39So some people at NASA would say,
12:41well,
12:41why can't you just measure what's
12:43happening with the aircraft?
12:45But of course,
12:46we don't have valid studies showing
12:47that measuring changes in you
12:49know the way a pilot performs in
12:51controlling their aircraft would
12:53actually tell us something meaningful,
12:55and so we decided that what
12:57we really needed was a.
12:58A handheld device that would
13:00give us reliable information,
13:02and so we set out to develop the NASA Pvt.
13:06And while there were other PVT's
13:09available in the App Store at
13:11the time that I came to NASA.
13:14There were there are issues with lots
13:17of them and and most of the pieces
13:21that were available in the App Store
13:24were not built with the same sort of
13:27rigor and care that the laboratory
13:29versions of this test include.
13:31So for example,
13:33in a typical laboratory Pvt you want
13:35a participant to have the ability
13:38to respond with either thumb,
13:40because responding with the
13:42wrong thumb tells you something.
13:44Kind of important about their reactivity
13:46and many of the PTS would just have
13:49like a little simple like flashing light
13:51that would have appear on the screen.
13:54Similarly, the original Pvt.
13:55192 has numbers that scroll up,
13:57so that gives you some feedback.
13:59So as a person taking the Pvt you
14:01can see how your reaction time is
14:04changing with each response trial
14:06and over the course of a day.
14:08And so we felt that having that
14:10feedback was pretty important for the
14:13participant population that we work with.
14:15Because in addition to helping them to
14:17just sort of see how they're performing,
14:20we wanted them to stay motivated and
14:22so often having this feedback helps
14:24with motivation to take the tests,
14:26and so we we built this touchscreen Pvt.
14:29I have a developer or in my lab who
14:32told me it would take three days and
14:35it took about three years to develop,
14:37so is no small task.
14:39There are all kinds of issues with
14:42touchscreen devices from the way you
14:44hold the device to the system latency.
14:47That is,
14:47changing the response time from
14:49the time you hit the screen to
14:51the time it requires a response.
14:53So it took a lot more work than we
14:55ever thought it would need to take,
14:58but we were very happy with this final
15:00product and we tested it in the lab
15:03using a constant routine protocol
15:04and compared it to the original Pvt.
15:07182 and I won't go through this in
15:09detail because this is again not the
15:12interesting really part of my talk.
15:14But what we found is that you do
15:16respond a bit faster with the Pvt.
15:18192 because you're.
15:19Tom is right on the response button.
15:22You can respond with bit faster,
15:24but the touchscreen device where
15:25you hover your thumb is pretty
15:28close and has a nice alignment,
15:29and so we were very happy with the.
15:32These are just all different metrics
15:34from the PBT and they all look
15:37pretty similar between the Pvt.
15:38182 and the NASA PBT.
15:40So we felt good about taking
15:42this into the field.
15:43And so we built a nap around it.
15:47And so again,
15:48kind of going back to those
15:51fundamental questions that I was
15:53looking to answer when I came to NASA.
15:56I wanted to have a tool that would make
15:59data collection easy for participants
16:01and so we built this app so that it
16:05would have logic to take our study
16:08participants through each activity
16:10in the protocol at the right time.
16:13So it prompts PVT's when
16:15they're supposed to take BTS.
16:17Subjective scales when they're
16:19supposed to take those.
16:20It includes a sleep diary that
16:22prompts before bad in the morning,
16:24and it has a bunch of baseline
16:27questionnaires, workload, ratings,
16:28and other.
16:31Information relevant to the
16:32things that we do and I'm pleased
16:35to say that if you need a tool,
16:37this is now free in the App Store,
16:39and so there's a basic version
16:41with just sleep diary in three PT.
16:43Today there's a simple PPT and then if
16:45you happen to be doing aviation studies,
16:48there's also a version for aviation,
16:49so feel free to check that out.
16:52So armed with this app,
16:53we embarked on our first study.
16:56And so the first research
16:57question that we had is, you know,
17:00let's going on the short haul aviation.
17:03We have many airline partners at
17:05NASA and there's been a lot of study
17:08dedicated to longhaul aviation
17:09jet lag circadian misalignment
17:11when crossing time zones.
17:13We have a pretty good understanding
17:15of what happens when pilots are,
17:17you know,
17:18traveling for long distances and we
17:21have pretty good rules in place for
17:23what they need to do in order to stay.
17:26Alert and get the rest that they need,
17:29but there are very few short all studies.
17:31In short haul flights.
17:32You know, while many of them
17:34are considered daytime flights,
17:35you know we've probably all been
17:37on a flight that left at 5:00 AM.
17:39Well,
17:40if your flight left at 5:00 AM,
17:42your pilot probably had to get up
17:44at two or three in the morning in
17:46order to be fit for duty and be at
17:49the airport and be ready to fly.
17:51And so you know,
17:52I think in the sleep community we
17:54wouldn't say you know that's not really a.
17:57You know a daytime shift that's
17:59really a night time shift,
18:00and so we wanted to explore what
18:03happens when pilots have to work
18:05early in the morning, finish,
18:06work late,
18:07or work under conditions of high workload.
18:09So we worked with an airline,
18:11a single airline to develop this protocol,
18:14and I'll just draw your attention
18:16to this plot on the right,
18:18which shows the protocol.
18:19So each row represents a day.
18:22And so this protocol is 34 days.
18:25It's plotted as I bought a 30
18:28hour period across the conceit.
18:30I'm on the bottom and what we have
18:33here is like rare sleep opportunities.
18:36This is midnight,
18:37so you can see this pilot can sleep
18:40around 11 to maybe around 7:00 in
18:43the morning and then these darker
18:46Gray regions are flights and So what
18:49you can see here is we varied their
18:52schedule from a baseline block of five.
18:55Chefs where they were flying kind of in
18:58the late morning to mid to late afternoon.
19:01Very easy.
19:02Typical schedule for daytime worker
19:04and that was our baseline and then
19:07we had gave them a few days off
19:09and shifted them to an early start
19:12schedule where they had five days
19:14where they started work at between
19:174:45 and 6:00 in the morning.
19:19And then they had a few days off
19:22and shifted to a middle of the day
19:24schedule where they had longer flights,
19:26more ups and downs.
19:28They had few days off,
19:29then we shifted them to a late schedule
19:32where they finished you typically
19:33after midnight and we collected
19:35the psycho motor vigilance task.
19:37At each of the times shown
19:39on with these icons.
19:41So when they woke up on each
19:43flight and then before bed.
19:45And then we also collected data on
19:48days off and in addition to that
19:51we had them do urine collection
19:53at the end of each blocks that we
19:56could assess circadian phase and
19:58we had them collect a variety.
20:00Other measures that I won't
20:02talk about here and then.
20:03The last pieces we had them where
20:06at an act watch the entire time
20:08so that we could assess sleep in
20:11addition to their sleep diary.
20:13And overall, the.
20:17Pilots, were, you know, relatively young,
20:19relatively healthy overall,
20:20so we didn't see a lot of indications
20:23that there were sleep disorders
20:25in this population.
20:26I'm showing that I make you score here,
20:29they're pretty much squarely in the middle,
20:32not know extremes in morning this evening.
20:34This which I found very interesting.
20:36And then I'm not showing some of the
20:40others questionnaires that we use,
20:41but the PSQI for example showed
20:44that there wasn't a big cause
20:46for concern with sleep disorders.
20:49When we look at their sleep outcomes
20:51over the four different schedule types,
20:53we found that they got less
20:56sleep during early starts.
20:57As you can see here.
20:59So at baseline they got around 7
21:01hours a night and again we designed
21:03the schedule so that they would
21:05maximize their sleep opportunity
21:07and that remained for their midday
21:09in their late schedules.
21:11But for their early starts they
21:13last about an hour of sleep,
21:15and as you can see over here in the plot.
21:19By each day on that schedule
21:21they they didn't really recover,
21:23so their sleep dropped dramatically
21:25after the first early morning
21:27shift and stayed low across the
21:29course of the five days.
21:30So this was a concern for us that these
21:34early starts were affording them less
21:37sleep than they really needed to be able to.
21:40Function during the day and then when
21:42we looked at performance we found
21:44that in fact their performance was
21:47affected by this short sleep duration.
21:49So what we have here is if you
21:52look just across the bottom,
21:54SIS is reaction time on the Pvt.
21:56So up is bad is a slower reaction time
21:59and lapses are response times that
22:01are greater than 500 milliseconds.
22:03And what we found is that on our
22:06baseline schedule it did exactly
22:08what we wanted it to for each
22:10day on that schedule.
22:12They maintained a pretty stable
22:13performance which was great.
22:15We were very happy to see that,
22:17but on each of the other schedules
22:20their performance declined,
22:21so it didn't matter whether it was early,
22:24starts, midday, or late finishes on the head.
22:27Poor performance with each day
22:28accumulating and getting worse by the day,
22:31so again,
22:32this is concerning,
22:33and it suggests to us that
22:34there is a chronic
22:36sleep debt accumulating over
22:37the course of this time,
22:39and perhaps also some circadian influence,
22:42particularly for the late finishes well.
22:44They were required to stay up
22:46and fly until after midnight and
22:49we looked at circadian phase.
22:51We found that at baseline there
22:53means circadian phase was right
22:55around 4:00 in the morning,
22:57where we would expect it to be,
23:00and we found that they did shift
23:03some prior to the early starts.
23:05Couple of hours early shifted later
23:08again during the midday flights,
23:10and then later again following the
23:12late finishes. So we did see some.
23:15A circadian adjustment,
23:17probably related to their nap.
23:19Trouble a pattern of light exposure,
23:22but this didn't seem to help in
23:24increasing their sleep duration
23:26or improving their performance.
23:28And when we look.
23:30At this in total,
23:31our big concern or big flag
23:33was in early start.
23:35So well late finishes and the midday
23:37high workload flights resulted in
23:39poor performance relative to baseline,
23:40but it really starts resulted in both
23:42short sleep and poor performance,
23:44and this isn't particularly
23:46surprising because we all know that
23:48when you try to sleep during weight
23:50maintenance down when you try to
23:52sleep a few hours earlier than normal,
23:54even if you have to,
23:56you know you have to get up early to
23:59take a flight yourself, for example.
24:01It's very hard to get adequate
24:03sleep because your body is just
24:05not aligned to have sleep start at
24:08that time and so we decided that.
24:10Well,
24:10actually we didn't decide when
24:12we took this to the airline.
24:14They said, OK, well, that's terrible.
24:16What are you going to do about it?
24:18And this was a little bit surprising
24:21and exciting to me because coming
24:23from an academic world,
24:24you're really living from 1
24:26grant to the next.
24:27And now in the supplied world,
24:29you know our partners are
24:31really looking for solutions.
24:32And so it was very exciting to be
24:36able to think about how we might
24:39be able to solve this problem.
24:42And so after had a good deal of
24:46conversation about what we could do
24:49and what the best approach would be
24:52to try to increase sleep duration and
24:55performance on those early starts,
24:58we decided to evaluate a lighting
25:01countermeasure and as Lauren mentioned.
25:03I have a background in basic
25:05circadian Physiology and studying
25:07the influence of light on the
25:09human circadian system and so
25:10this is very much aligned with
25:12that basic science background,
25:13and I thought it was really nice
25:16next step for for trying to solve
25:18this problem so we know that light
25:20follows a phase response curve or
25:22the circadian response to light
25:24causes phase response curve.
25:25I should say so again,
25:27I'm sure you're all very familiar with this,
25:30but just put simply,
25:31you know,
25:32light in the biological morning
25:34is going to shift.
25:35Sleep and wake earlier and allow
25:37for a better phase advance.
25:39We know that the flight crew that
25:41we work with for these early starts
25:44often begin work before sunrise.
25:47And so you know, if we look
25:49at the phase response curve,
25:51what we were aiming for was to get a light.
25:56Stimulus somewhere around here in
25:58order to try to get a maximal phase
26:01shift to enable them to be able to
26:04fall asleep earlier in the evening
26:06to obtain more sleep and then
26:09hopefully improve their performance.
26:10But in the lab, in my experience,
26:13we would often use very large
26:15devices like boxes or specialized
26:17lighting systems that weren't very
26:19conducive to application in the field,
26:21and so for this purpose I looked at
26:24seasonal affective disorder lighting.
26:26In order to have a more portable
26:30countermeasure that might be.
26:32Useful for pilots in the real world,
26:35and so we went back to the airline and we
26:38decided just designed a similar study,
26:42but this time we had them complete a
26:45baseline block followed by an early
26:48starts block and then another baseline
26:51block and an early starts block,
26:53and in each of the early starts
26:56lock box we randomize them to either
26:59have where placebo glasses that.
27:02Um did nothing,
27:04so playing unfiltered glasses really
27:06safety goggles or illuminate goggles.
27:09So if you're not familiar with the luminette,
27:13it's a.
27:14Just a little looks like a funny little
27:171980s kind of sunglasses type deal,
27:20but it shines light in your eyes from
27:23the front and you can still walk
27:26around and get ready and do things
27:28while wearing the luminette and it
27:31has a peak in the blue wavelength region,
27:34which we know is the most potent
27:36for circadian synchronization
27:37synchronization and it generates
27:39about 1500 that Lux of light.
27:41So we're really excited about this
27:44as being a nice way to enhance.
27:47The pilot light exposure in the
27:49morning to hopefully again create
27:51a bigger circadian phase shift.
27:53We asked them to wear them for 25 minutes.
27:57When they woke up before their early starts,
28:00and then just some important notes
28:02about this particular study.
28:04It was conducted in the fall,
28:06so during evening darkness and later
28:08sunrises, the pilots always returned home.
28:11So and that was true for the first
28:14study as well.
28:15So while they did fly.
28:18Tom,
28:18you know two different destinations.
28:20We didn't want the influence of sleeping
28:22in the hotel to add noise to our study,
28:25so we had the airline designers so
28:28that they would always fly home and
28:30sleep in their their local home bed
28:32every night and justice before we
28:35collected the PBT at all of the same times.
28:38Once during each flight and then
28:40at the beginning and end of the day
28:43and then on their off days as well.
28:45And we collected all of the same measures.
28:49And we found that this particular
28:51group of pilots was pretty similar.
28:53So in this case we had 30 in the
28:56first study we had 44, and you know,
28:59demographically, again,
29:00pretty healthy people.
29:03The compliance when using both placebo
29:05and the light glasses was very good,
29:07so we asked them to wear them for
29:1025 minutes
29:10before each of the early starts.
29:13They wore them on 93% of days and they wore
29:16them for pretty much the entire time that
29:19we asked them to wear them if not more so.
29:22We found that the use of the glasses
29:25was not at all the hindrance in
29:28their ability to complete the study.
29:30Unfortunately, though,
29:31we didn't find any difference in sleep
29:34outcomes and so when we look over here,
29:37the main lines that I'll draw your attention
29:40to are just the blue and the red line,
29:44and so the blue line is the light
29:47and the red line is the placebo,
29:50and each of these is a day on the schedule.
29:53So Day 12345 and so on.
29:56This is sleep duration,
29:57and this is a little bit tiny.
30:00So I apologize,
30:01but this is 6 hours right here,
30:03and So what you can see is their
30:06sleep was basically the same.
30:08You know,
30:08it doesn't even matter what the duration is.
30:11Their sleep really did not
30:12improve throughout the schedule.
30:13We may have seen a little
30:15bit of a bump at the end,
30:18but but it was present in the placebo as well
30:21and then the same is true for sleep latency.
30:24No improvement,
30:24but it does decrease overtime,
30:26but that's probably a function of them
30:28becoming progressively more sleep deprived.
30:29No differences in efficiency.
30:31And no differences in way so so
30:34this was quite disappointing,
30:35but of course you know if maybe we were
30:38able to further shift their circadian phase.
30:42Maybe their performance improved,
30:43but unfortunately that
30:44was not the case either.
30:46So we found that their performance again,
30:49the blue is the light glasses,
30:52the red is the placebo on their performance,
30:55mapped right on top of one another through
30:58for each day of the schedule we saw it.
31:02No differences whatsoever with the
31:04Lunette glasses in the morning,
31:06so this was quite disappointing.
31:08Quite quite disappointing and so
31:10our conclusion here is we don't
31:13see any improvement with this
31:15enhanced morning light exposure.
31:17I didn't show you circadian phase here.
31:20We haven't actually assessed all of that yet.
31:23This is a fairly new study.
31:26It's not published yet either,
31:28but I don't even know if we
31:31did shift circadian phase.
31:33If in this in this real world setting
31:36if we didn't improve alertness,
31:38performance and sleep,
31:39you know it's not likely to be a
31:42particularly valuable countermeasure
31:43in the long run.
31:45So upon reflection,
31:46you know we think either the light
31:49was maybe not bright enough for
31:51the duration was not long enough,
31:53but more likely I think that evening
31:56light exposure probably inhibited
31:57the pilot's ability to sleep,
31:59because if we look at the
32:02phase response curve to like.
32:04You know a lesser amount of
32:06light in the evening has a large
32:09impact on shifting phase later,
32:11and so we suspect that you know
32:13we need to do a lot more work
32:16educating the pilots on sleep
32:18hygiene and the importance of
32:20turning off those screens in
32:22the evening in order to allow
32:24them a longer duration of sleep
32:27in order to maximize the benefit
32:29that they might get from like that.
32:31As things stand now, we don't have.
32:35Further, plans to roll this out,
32:37although we may,
32:39we may conduct another study in the
32:42future where we we try to focus more
32:45on sleep hygiene in addition to.
32:48How to measure that we introduce so
32:50that gives you a snapshot of the
32:53type of work that we do in aviation
32:56we have a variety of other studies
32:58happening on different topics
33:00but leave leave you here for the
33:03aviation and I will switch gears and
33:07talk about sleep a little higher.
33:09The outside the atmosphere so here
33:12will just begin to talk about are
33:15there differences between sleep
33:17on earth and sleep in space,
33:19and so just before I move on,
33:22I'll just say this is a picture
33:25of Senator John Glenn in the 1990s
33:28he returned to space on the space
33:31Shuttle in order to test the effect of
33:35spaceflight on the aging human body,
33:37and we've learned a whole lot.
33:40About how spaceflight effects the
33:42aging human body from this case study,
33:45including on how space affects
33:47sleep in an older person.
33:49I'm not going to talk about that right now,
33:53but I will say you know that that
33:56is something that we're working on.
33:59We're actually going back and looking
34:02at the data from his neurolab mission,
34:05the PSG to, you know,
34:07sort of further assessed how.
34:10State this basically measurement
34:12affects sleep architecture in younger
34:14and older people, but we're very,
34:17very fortunate to have his
34:20participation in that study.
34:22So to begin with,
34:23the study that I'm going to talk about,
34:26really,
34:26the motivation for this study came
34:29about because in all of the studies
34:31that have been done on sleep and
34:33space or all the studies that
34:35have been done up to the point
34:38where we started this study,
34:39it was pretty clear that sleep in
34:42space is shorter than it is on Earth,
34:44certainly shorter than it should be.
34:48On Earth, and so you can see,
34:51no matter how you measure weather
34:53with EG or we sleep logs,
34:55the astronauts are getting.
34:57Less than 7 hours of sleep a
35:00night and were typically hovering
35:02around the six hour range,
35:05and so this is a concern,
35:07of course,
35:08because when we talk about the
35:10need for astronauts to perform at,
35:13you know their peak all the time
35:15and we think about the potential
35:18consequences of a mistake in space.
35:20You know this is quite concerning.
35:23We want to make sure that
35:26the astronauts have the.
35:28Rest that they need to be able to perform
35:31at the highest level all the time,
35:34and so in thinking about this.
35:36Of course we wondered.
35:38OK,
35:38well,
35:39you know what are the causes for
35:41that short sleep,
35:43and so the first thing that as
35:45the circadian physiologist and
35:47coming from working with checks
35:49Eisler and Laura Barger,
35:51who were my early mentors on this project?
35:55You know, one potential issue is circadian
35:57misalignment and so a few things.
35:59There are a few things about many things
36:01about space that are different than on Earth,
36:03but one of the most notable is that the light
36:05exposure pattern is different, and so on.
36:08Earth, you know the sun does.
36:11It does the work for us for entrainment.
36:13If we stay awake during the day,
36:15we sleep at night.
36:17We will generally staying trained
36:18but in space the shuttle orbits the
36:20Earth or the State Space Station.
36:22In this case orbits the Earth every
36:2445 minutes or every 90 minutes,
36:26and there's a 45 minute sunrise sunset.
36:29And if you have Windows which the
36:31space station and the shells do,
36:33you can get exposed to light at the wrong
36:35time or not have light at the right time.
36:38But there's also schedule
36:40induced circadian misalignment.
36:41So this is an active act watch output
36:43from a special mission and what
36:45you can see is that the schedule
36:47shifts earlier every single day,
36:49and that's a function of orbital dynamics.
36:51So when we ran the space shuttle missions,
36:54the shuttle would have to launch and
36:56land at particular windows of time and
36:58they in order to orbit the Earth the
37:01correct number of times to be in the
37:03right position for launch and landing.
37:05The crew would have to adjust
37:07their sleep every day,
37:08and so we know that phase
37:10advances are really hard.
37:12There were many phase advances on
37:14space Shuttle and then our Apollo
37:16missions were really know better.
37:17This is more a function of the
37:20workload on the astronauts sleep
37:22which shifted all over the place.
37:25Apollo missions and so we know
37:27that we have lots of potential
37:29causes for circadian misalignment.
37:31We also know that the prior
37:34samples were pretty small.
37:36There were variable machine conditions there,
37:38stressful workload,
37:39and particularly on a
37:41space mission like Mirror.
37:42There were a lot of near catastrophic events,
37:45and so you know,
37:47we really thought to ask the question here.
37:50Why do astronauts sleep less in space?
37:53And is that still continuing today?
37:56Or was that just an artifact of history?
38:00Is sleep duration longer on
38:04long duration missions so?
38:06Is there a here Mike?
38:07Is there a question or is that
38:09just an open mic?
38:14Sounds like somebody has an open mic. So
38:18I'll continue and hopefully
38:21hopefully that'll be OK so.
38:26So for long duration missions,
38:27astronauts don't have quite
38:29the workload that they had.
38:30In short duration missions,
38:32and so we wondered if maybe just
38:34being in space for longer would
38:36adapt them to the environment and
38:38allow them to get longer sleep.
38:39And then we wondered what countermeasures,
38:41if any, they're using to enhance sleep.
38:44And if they're using countermeasures,
38:45are they effective.
38:46So again,
38:47just specific games we wanted to
38:49compare sleep duration for in space to Earth.
38:51We wanted to compare sleep duration
38:53from in long and short duration missions.
38:56Look at hypnotic specifically and then
38:58we wanted to assess the influence of
39:01circadian misalignment on sleep outcomes.
39:03So we conducted two different studies,
39:06one in short duration astronauts
39:08flying on the space shuttle and went
39:11on long duration missions with crew
39:13members living on the space station.
39:16We collected data 90 days
39:18before they launched.
39:19For two weeks,
39:20they completed sleep logs where
39:23they indicated their bed and
39:25wake times and medication use.
39:27And we're an app to watch
39:29during this period of time,
39:31we collected data for the 11 days
39:34prior to launch up until launch,
39:37and then throughout the mission and
39:39then seven days after they returned
39:42and for the circadian phase estimation,
39:44we used by mathematical modeling by
39:47taking the actigraphy data and modeling
39:50circadian phase to assess periods of
39:53time when they'd be in and out of phase.
39:57But overall we had a very large
39:59participation in this study.
40:00So in our short duration mission,
40:02we had 60 for 64 crew members and in
40:05our long duration study we had 21
40:08crew members and you can see there's
40:10very large number of days in flight.
40:13And then of course notably the
40:15difference here is that for short
40:17duration the crews were in space for
40:19just under 2 weeks on average and for
40:22long duration they were in space for
40:24several months and average about 155 days.
40:27Importantly, NASA schedules astronauts
40:28for 8 1/2 hours time in bed every day.
40:32So the results that I'm going to show
40:34you are not simply an artifact of cruise.
40:37Choosing to sleep less, they have an
40:40allocated out of time specific for sleep.
40:42So this is sleep obtained.
40:44Given that timing back.
40:46So what we found was.
40:49Sleep duration is shorter
40:52in space relative to.
40:55Relative to an earth,
40:57and so this is in flight and you
41:00can see compared to post flight
41:02it's shorter and this is also
41:05shorter compared to the pre flight
41:07and the 90 days before flight.
41:10Just and we didn't see any differences
41:13between short which is the light
41:16Gray and long duration missions.
41:18When we look at the counter
41:20measures that they use,
41:22we find that there's a high prevalence
41:24of hypnotic use in among astronauts,
41:26and So what you can see here in this
41:30chart is if a box is shaded in Gray,
41:33it means that on a particular
41:35night crew member didn't
41:37take any sleep medication if it shaded
41:39in blue, they took medication 11,
41:41hypnotic that night,
41:42and if it's shaded in red,
41:44they took two hypnotics that night,
41:47and So what you can see here is.
41:51Each box represents a day in space.
41:53In each row represents a single crew member.
41:55So for example, if we just look at the top,
41:59there are two blue boxes at the tops of this
42:01person only provided us with two data points.
42:04But this is 1 crew member and for both of the
42:07days that they completed the sleep diary,
42:10this person used a hypnotic.
42:11So you don't have to look at every
42:14single row, just the general pattern.
42:16You can see that there is a widespread
42:18use of hypnotics with some crew members.
42:21Serve habitually using more than one dose
42:24of hypnotic every single night in space.
42:26So overall, we found that 78% of
42:29participants used hypnotics at least once,
42:31and they were using them 52% of
42:34all nights in space and then.
42:37Creates more than windows on 18% next.
42:40However, hypnotics don't really
42:43seem to provide a very.
42:47Positive impact,
42:47so sleep latency is shortened by about 10
42:50minutes and we think that this is probably
42:53driving the continued hypnotic use.
42:55They fall asleep faster and as a result
42:58they keep using sleep medications,
43:00but we don't see differences
43:02in sleep duration, alertness,
43:03sleep efficiency,
43:04quality,
43:04or any of the other outcome measures
43:07that we looked at.
43:11Now switching gears to
43:13circadian misalignment.
43:14So we took all of our long duration
43:17data from the 21 crew members who were
43:20in space for 155 days on average,
43:23and we applied that by a mathematical
43:25model to assess circadian phase
43:27from the actigraphy data,
43:29and what you can see here is these are.
43:32So each row represents a day.
43:35Again, here in this roster
43:37plot and Gray is sleep and.
43:39What you can see is firstly there is a
43:42lot of change in their sleep pattern.
43:45This is 1 crew member another and another,
43:48and so you can see this crew member.
43:50These are not the same time in space,
43:53so they all the crew sleep actually
43:55at the same time every night.
43:57But we can see here is that there
44:00are sleep is really changing
44:01in terms of scheduled time.
44:03So here where sleeps shifts
44:05way out and then comes back in.
44:07This is probably a situation
44:09where a Soyuz vehicle or a.
44:11Resupply vessel arrived at the
44:13space station and the crew had to
44:16shift their sleep to be able to
44:18be awake when the vehicle arrived
44:20and then they shifted back to GMT
44:23stable time after vehicle left.
44:24The little white dots are the
44:26estimates for core body temperature
44:28minimum and what you can see is when
44:31the little white dot is outside
44:33of the sleep episode.
44:35We would consider them to be circadian
44:37misaligned and you can see many
44:39places where crew circuiting this line.
44:41And did someone have a question?
44:47Maybe not. So when we look at the
44:51consequences of the circadian misalignment.
44:54Again, there are misaligned one
44:55out of every five days in space.
44:58It looks like it's mostly schedule driven,
45:00but we find that it has huge consequences
45:02and so they lose about an hour sleep when
45:05they're sleeping out of circadian phase
45:07compared to when they're sleeping in phase.
45:09And when we compare this to the effective
45:12hypnotics where we didn't really see a big
45:14difference or improvement in sleep duration,
45:16one of the things that we're taking
45:18forward is just by maintaining
45:20them on a regular schedule.
45:21We can probably increase their
45:23sleep duration, too, you know.
45:25Little more than six hours.
45:26Probably not a lot,
45:28but at least a little bit
45:30more than six hours,
45:31so this was really important in thinking
45:34about how we might build schedules going
45:37forward from an operational perspective.
45:39When we look at a sleep medication
45:42use during nights when they
45:44were aligned versus misaligned,
45:46we find that they not only took more hypnotic
45:49medication nights when they were misaligned,
45:52but they also took more of any medication.
45:55So I think this really illustrates the.
45:59Impact of circadian misalignment on just
46:01you know your well being and probably
46:03translates to shift workers as well
46:05because when we are circadian misaligned.
46:07When we're working against our body Clock,
46:10you know there are caps Gator,
46:12but other symptoms from other causes
46:14that can you know cause us to reach
46:16for medication as a solution that it
46:19certainly was happening on the space
46:21station and we think that the prevalence
46:24of sleep medication is higher here.
46:26Misaligned nights,
46:27because when they are misaligned we
46:30suspected they had more difficulty
46:32falling asleep and staying asleep,
46:34which led to them reaching for
46:37hypnotic to help.
46:39So overall,
46:40from the this actigraphy study we find
46:44that sleep duration is shorter in space that.
46:49Hypnotics are particularly effective
46:51for increasing sleep duration.
46:53They do increase or reduce sleep latency.
46:56Circadian misalignment is
46:57happening about 20% of the time,
47:00and it seems to be more schedule driven
47:03than related to light dark patterns
47:06right now and use of all medication is
47:10increased during circadian misalignment so.
47:13So I just I realized we're
47:15coming up to the end here,
47:17but I wanted to just tell you a
47:19little bit more about what the
47:21type of work that we do at NASA,
47:23and so I'm not going to go
47:25deep into these studies,
47:27but I just wanted to show
47:29you two really cool things.
47:30So firstly,
47:31we do fix space missions,
47:32so we have this analog called
47:35the human exploration research
47:37analog where we're preparing for.
47:39Lunar mission, so our goal right now,
47:41or at least as of the last administration,
47:44was to go to the Moon by 2024,
47:47and so we're doing missions
47:49with four crew members,
47:51and we keep them in isolation.
47:53In this habitat,
47:54we have a fake Mission Control,
47:56and this allows us to study
47:58them and study their
47:59team interaction and their response
48:01to stressors like isolation
48:03and confinement and sleep loss.
48:05And for this particular
48:07study we were interested in.
48:09Also, assessing the influence of
48:10bio mathematical models and how
48:12well they are able to predict
48:13alertness and performance.
48:14And so again, I'm not going into depth here,
48:17but this is an example of a study
48:19that we did in the habitat.
48:20It was just published a few months ago.
48:23If you're interested,
48:24you can certainly have a look at it,
48:26but we studied for cruise over 5 missions.
48:28They were restricted to five hours
48:30of sleep per night during the week
48:32and they were given 8 hours of
48:34sleep on weekends and they stayed
48:35in the habitat for 45 days,
48:37so we wanted to make this similar to what
48:40a future lunar mission might look like.
48:42And each triangle here represents
48:44a time when we had them take a
48:47reaction time test and a stamp rally
48:49fatigue rating through the day.
48:51And So what we found just in terms
48:54of performance was that average
48:56performance didn't change a whole
48:58lot over the course of the mission.
49:00But we saw pretty broad Inter individual
49:03differences with some people being
49:05high performers and resilient.
49:06Despite this pretty extreme sleep
49:08loss and some really being sort
49:11of affected very much by this.
49:13Habitat and this sleep restriction.
49:15So again,
49:15we're taking this information for
49:17we also I'm not going into the
49:20bio mathematical modeling,
49:21but we did learn a lot about how about
49:24mathematical models can be used to
49:26predict alertness and performance,
49:28and then the last thing that I
49:30wanted to show you is just what
49:33we're doing for Mars.
49:35So the cool thing about Mars
49:37is that it rotates.
49:41The rotation is 24 hours 39 minutes,
49:43so it's incredibly close to Earth.
49:45None of the other planets are anywhere
49:47near the ballpark of our rotation,
49:49so it's really close,
49:50but as you know, probably from
49:52reading forced desynchrony studies,
49:54it could be just long enough that it's
49:56a problem for some people to entrain,
49:59and when we send row.
50:001st to Mars. This is curiosity.
50:02The scientists and engineers
50:04who work to control those Rovers
50:06will live and work on Mars time.
50:08They'll live on a 24 hour,
50:1039 minute day everyday and
50:12shift a bit later every day,
50:14and so we can study them to see how well
50:17people are able to shift to Mars time.
50:20And we can also introduce countermeasures
50:22to see if we can adapt them to
50:25live in on a Mars day length.
50:27And so we took the opportunity
50:29to do that during actually the
50:31Phoenix Mars Lander project.
50:33And this is a one of the engineers,
50:36and we use blue light boxes at
50:38their workstations and we assess
50:40their circadian phase and had the
50:42more active watches throughout
50:44the entire mission duration.
50:46And we found that in fact they did
50:48out of the 20 people that we studied,
50:52all but one were able to adjust to
50:54this March time and so we think that
50:58with appropriate countermeasures we
50:59will be able to help the astronauts
51:02adapt when we do eventually go to Mars.
51:06So finally,
51:07just to summarize,
51:08with this sleeping space part,
51:10we have more to do.
51:12We're assessing sleep architecture.
51:13I've been working hard to resurrect
51:16archival data.
51:17We have a paper under review right now
51:19looking at sleep spindles from the shuttle
51:22mission I mentioned with Senator Glenn.
51:25We I've worked with Bob Stickgold,
51:28who collected data on REM sleep on mirror
51:31that was never published 25 years ago,
51:34and so we're working to do
51:36a final analysis of that.
51:39We're continuing to look at countermeasures
51:41so we have special lights on station
51:44that should help the crew and train.
51:46Of course,
51:47we're working to stabilize their schedules.
51:49We need to look at wake
51:51for money medications,
51:52and then we also need to look
51:55at performance in flight.
51:57And so we have.
51:58Of course Nastic gives out grants
52:00and doctors Brainard and Lockley
52:02at Thomas Jefferson and Harvard
52:04and images and Bazner at Penn
52:06have grants to assess these.
52:08Counter measures and performance issues.
52:10So with that this is my team.
52:13I just like to say thank you.
52:17Acknowledge all the people who
52:19worked on these studies and
52:21happy to answer any questions.
52:25Thank you so much, that was a
52:27fantastic talk. Doctor Flynn Evans.
52:30You hear me OK? Sure can.
52:33Yeah I had to switch devices mid talk
52:35so I just want to welcome everybody to
52:38please put any questions in the chat.
52:41I see that there are a few there
52:44already while I take a look at those.
52:47I was just wondering if you might be
52:49able to comment on something from
52:51your one of your later studies.
52:54You just alluded to the individual
52:56differences in resistance to sleep
52:58loss and circadian disruption.
52:59An I was wondering if there's any.
53:02Part of the screening to become either
53:05an astronaut or a pilot that attempts
53:07to get it that in any way currently.
53:10Great
53:11question. Yeah, unfortunately there's
53:13not right now and so we have talked
53:17about looking at polymorphisms that
53:19might be associated with resilience
53:22or vulnerability to sleep loss.
53:25You know, we know that per three polymorphism
53:28is associated with vulnerability,
53:31but the crew there's a.
53:35Were prohibited from looking at
53:37genetic information among the crew
53:39for the purposes of selection.
53:41And so, while technically we probably
53:43would say it's not for selection,
53:46but maybe more for strategic
53:48application of countermeasures,
53:49the law prevents us from being
53:51able to do that at this point.
53:54And So what we do, we do what we can.
53:58So we do typically have the crew do
54:00tests of different hypnotics on Earth,
54:03and then we have them wake themselves up.
54:07You set an alarm for like you know,
54:10midnight and wake up and do a Pvt just
54:13to sort of test do it self test to
54:17determine whether or not they'll be
54:19vulnerable after taking a hypnotic.
54:22We also work with them as they
54:24travel across time zones on Earth,
54:27and if anybody is appearing particularly
54:29vulnerable then we'll work with them.
54:32Kind of in a very personalized medicine
54:35approach to Taylor or fatigue.
54:37I did not plan to that person.
54:40Interesting great. Well thank you.
54:42I see one of the questions that was
54:45posed as can you discuss what, if any,
54:48affects microgravity has on the Physiology
54:50that might disrupt sleep in space?
54:52I don't know if you know anything
54:55that specifically. Yeah, it's a
54:57huge question. So the way that I think
55:00about our work is we have to get rid
55:03of all of the problems that we know are
55:06problems for people sleeping on Earth.
55:09And then will should.
55:11We should be able to assess the
55:13influence of microgravity on sleep.
55:15So it could be that the crew can't
55:17sleep more than six hours because
55:19their sleep environment is terrible.
55:21In addition to being circadian misaligned,
55:23it could be that they you know are just,
55:26you know, it's probably not
55:28an issue like excitement,
55:29because we don't see that there's
55:31improvement in the long duration flights.
55:33But basically we really have to make
55:36sure that we have their schedules aligned
55:38so we can look in a very pure way.
55:41To see if there's residual problems after.
55:46All of the more typical shift
55:47work type problems are gone.
55:49I suspect there is an influence
55:51of microgravity,
55:52and right now most of that evidence
55:54points towards the glymphatic system,
55:56and so you know,
55:57we know that during slow wave sleep.
56:00There is a whole lot of interesting
56:03stuff going on, I'm sure.
56:05Probably most of you attended the
56:08sleep meeting this year and the you
56:11know plenary talk was incredible and
56:13so you know the way that slow wave
56:16sleep is associated with just improved
56:18performance and lack of slowly sleep.
56:21Businesses here was development of
56:23Alzheimer's disease is something
56:25that we're looking at related to
56:27the lymphatic system and you know,
56:29just the waste product.
56:31Being flushed during sleep,
56:32so I'm very eager to use the archival
56:35data that we're collecting or that
56:38we're assessing to encourage now
56:40set to allow us to study sleep
56:43architecture in space again to
56:45see if there are changes in,
56:47say,
56:48slow wave sleep during spaceflight.
56:51Great thank you and maybe one last question,
56:55so this is from Ian Weir.
56:58Is there any data that shows that
57:02performance on the Pvt translates
57:04to actual job performance?
57:07And relatedly, did your studies
57:10any flight simulation data? Yeah,
57:13that's a really good question,
57:14so we actually do have all of so
57:17for the flight data we have all of
57:19the aircraft event data as well,
57:21so we know if the pilots were
57:23flying at the wrong altitude.
57:25We know if they were flying,
57:27their airspeed was too fast.
57:29We know if they taxi too quickly,
57:31if they hit their brakes too hard
57:33and we do see a relationship between
57:36the PBT in those aircraft outcomes.
57:38So I didn't go through that here,
57:40but that's pretty exciting
57:42because it does show that direct.
57:44Operational correlate there
57:45have been published studies,
57:47so Matthias Bazner showed a very
57:51nice correlation between the PBT and.
57:54Detection of weapons in TSA paradigm.
57:57So there there are some other
58:01studies that show some nice.
58:04Locations that the PBT is is
58:06relevant and is a sort of assay
58:09for the influence of sleep loss.
58:12Great,
58:12well thank you so much.
58:14And just to let everybody know our
58:16talk next week is going to be from
58:19Jacob Colin who is going to be speaking
58:22about sound sleep and PTSD and some
58:24veterans specific sleep issues.
58:26So please join us for that
58:28and thank you again.
58:29Doctor Flynn Evans for such a
58:31fantastic talk this afternoon.
58:35Great, thank you so much
58:36for having me have a great
58:37day everybody there. Thanks you too.