Most of us know that regular physical activity can strengthen muscles, burn fat, and lower our risk of heart disease. But many advantages of exercise go beyond physical fitness and cardiovascular health, according to Yale School of Medicine experts.
Five Yale Department of Internal Medicine specialists in areas ranging from infectious diseases to allergy and immunology discuss why exercise is key to optimal health.
1. Exercise reverses insulin resistance.
Studies led by Gerald I. Shulman, MD, PhD, George R. Cowgill Professor of Medicine (Endocrinology) and Cellular and Molecular Physiology, Investigator Emeritus of the Howard Hughes Medical Institute, and co-director of the Yale Diabetes Research Center, have demonstrated that exercise can reverse muscle insulin resistance.
“Insulin resistance in skeletal muscle is a major factor in the pathogenesis of type 2 diabetes, fatty liver disease, heart disease, and obesity-associated cancers,” said Shulman, who recommends daily exercise to promote cardiometabolic health. “There is also increasing evidence that insulin resistance may be a contributing factor in the progression of Alzheimer’s disease.”
2. Exercise aids in recovery from infection.
Exercise can reduce the risk of poor outcomes when infections occur, according to Scott Roberts, MD, assistant professor of medicine (infectious diseases). “For many infections, such as influenza, COVID-19, and RSV, comorbidities such as obesity, diabetes, and poor respiratory health are all major contributors to severe disease,” he said. “Exercise can help mitigate these risks and boost the odds of a speedy recovery.”
3. Exercise enhances immunity.
There is evidence that light to moderate aerobic exercise, like walking or jogging, can help the immune system work better, says Elise Liu, MD, PhD, instructor of medicine (rheumatology, allergy and immunology). “People who regularly get this type of exercise get sick less frequently than people who are sedentary,” she said. “This could be because several types of immune cells have been shown to work better shortly after exercise.”
4. Exercise contributes to a healthy gut.
Evidence suggests that exercise leads to a more diverse gut microbiome and an increase in butyrate, a short-chain fatty acid that may prevent disease, according to Avlin Imaeda, MD, PhD, associate professor of medicine (digestive diseases). “Butyrate is one of the key fuels that the cells lining the colon need to grow, divide, and stay healthy, and higher levels of butyrate can reduce the severity of inflammatory bowel disease and the risk of colon cancer, as well as general inflammation,” she said.
5. Exercise improves sleep.
Exercising during the day can help you sleep at night, notes Brienne Miner, MD, MHS, assistant professor of medicine (geriatric medicine). “Exercise is an external cue to your circadian clock, sending a physiologic message that lets your brain and body know when it is time to be awake versus when it is time to sleep,” she said. “A robust and regular circadian clock allows more regular and restorative sleep.”
Regular physical activity also contributes to better physical and mental health, decreasing the risk of developing sleep problems and potentially improving existing sleep problems, Miner said.
The Department of Internal Medicine at Yale School of Medicine is among the nation's premier departments, bringing together an elite cadre of clinicians, investigators, educators, and staff in one of the world's top medical schools. To learn more, visit Internal Medicine.