Good Sleep Recipe

Sleep results from 2 physiologic processes -- process S (homeostatic process) and process C (circadian process). Process S is the process by which a growing sleep debt or pressure occurs the longer one is awake. The currency by which the brain measures time awake is in the accumulation of adenosine. Adenosine is a byproduct of cellular metabolism, so the more active and alert we are during the day, the more adenosine builds up in the brain. Exercise for example can increase brain adenosine levels and through stimulation of adenosine receptors promote sleep. During sleep, adenosine is recycled and levels are reduced in the brain; less adenosine receptor stimulation leads to more alertness. In essence, the longer you’re awake, the more adenosine you accumulate, the more sleep pressure you acquire, and the more likely you are able to fall asleep at bedtime. Likewise, the less adenosine receptor stimulation there is, the more alert you feel. Caffeine is an adenosine-receptor blocker and promotes alertness. However, with habitual caffeine use, the brain may upregulate adenosine receptors over time, leading to decreased effect of caffeine or need for escalating doses. Therefore, to sustain the wake promoting effect of caffeine, it may help to take breaks from caffeine to downregulate brain adenosine receptors.

The circadian process (process C) controls the 24-hour cycle of alertness and sleepiness. Melatonin is the main orchestrator of process C, and melatonin is strongly influenced by light and dark exposure, but can also be affected by other zeitgebers (like food or activity/exercise). Within a 24-hour cycle, your best chance of falling asleep and the best quality of sleep will occur when your sleep drive is high (ie, process S is high), and your circadian level of alertness is low (ie, process C is low). Several disorders like depression or sleep phase disorder may lead to misalignment of process C and process S, resulting in insomnia or nonrestorative sleep. In these cases, a sleep expert should be sought to help align sleep processes for improved sleep quality.

Light and dark exposure are the most potent regulators of melatonin secretion, which in turn regulates your circadian rhythms including your sleep/wake cycle. To ensure you are sleepy at night, minimize light exposure, including light from electronics, at least 4 hours before your intended bedtime. Even an ordinary room light can suppress melatonin secretion, and melatonin is needed to help induce sleep. Melatonin is hypnogenic, and regulates hormone secretions during the night like cortisol, growth hormone, leptin and ghrelin which regulate alertness, metabolism and feeding behaviors. Similarly, to experience the most alertness and to anchor your sleep/wake cycle, make sure to expose yourself to bright light either in the form of sunlight or a light source of at least 10,000 lux for 30 minutes or more at the same time in the mornings.

Alcohol can impair sleep quality. While alcohol initially acts like a sedative and helps you fall asleep, as alcohol is metabolized during sleep, it’s metabolites can significantly disrupt sleep. Alcohol increases N3 sleep at the beginning of the night, but suppresses REM sleep, and causes significant sleep fragmentation and awakenings during the latter half of the night leading to overall nonrestorative sleep.

Your core body temperature naturally drops as your body’s melatonin secretion increases during night--this all to facilitate sleep. Studies show a cool sleeping environment not only helps induce sleep but also maintains sleep. In fact, it is well known that heat can dysregulate REM sleep and cause sleep fragmentation, while cool temperatures keep the body longer in N3 stage or deep sleep (the restorative sleep). To help fall and stay asleep, keep your room temperature cool between 63-68 degrees F. Taking a hot shower before bedtime may also help sleep since a shower dissipates body heat and cools the body temperature. Exercising initially causes an increase in body temperature but is then followed by a drop in core body temperature after an hour or so which may facilitate sleep.

We can train ourselves to fall asleep more easily by training ourselves to feel relaxed or less anxious in bed through a technique called stimulus control. You should avoid spending long periods of time awake in the bed especially if you’re feeling anxious, alert, or stressed, since this can develop an association of these feelings with the bed, interfering with sleep onset. The best thing to do, while counterintuitive, is to get out of bed when you’re unable to sleep, go to a nearby dark cool resting area and do some relaxation exercises or activities (like meditation, breathing exercises, biofeedback, light reading, for example) until you feel relaxed enough to fall asleep. Only then should you get back into bed. Stimulus control therapy (or sleep conditioning) takes time to work. In the beginning you may feel like you’re spending more time out of bed than in it, and with fewer hours of sleep, but eventually, your body learns or is “trained” to fall asleep more easily when you are ready to go to sleep. Some people who have chronic difficulty stopping their brain from ruminating while in bed or have difficulty detaching the feeling of stress from their bed, may benefit from cognitive behavior therapy for insomnia.