7.6 Sleep and Health Risks

Student Perspectives: Is Sleeping Really Related to Good Health?

Video Transcript

Good Sleep and Good Health: What is the Connection?

Good sleep provides a solid foundation for good health. Good sleep recharges our energy supplies and repairs our bodies. For example, growth hormone is released in higher levels during stages 3 and 4—deep sleep—and this fuels growth, boosts muscle mass, and enhances the repair of cells and tissues (U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2011). Further, optimal sleep has been shown to enhance athletic performance (Mah et al., 2011).

In a multinational study of about 17,000 college students ages 17-30, those who slept less than seven hours were more likely to report poor self-rated health than those who slept seven to eight hours. This difference remained even after adjustment for sex, age, smoking status, physical activity level, alcohol consumption, parental education, country of origin, depression scores, and use of health services (Steptoe et al., 2006). In other words, sleep is a major predictor of self-rated health. People who get adequate sleep are less likely to get sick. The body creates cytokines during sleep. Cytokines are cellular hormones that help the immune system fight infections. Thus, being well-rested improves the body’s ability to prevent and fight illness (U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2011; U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2017). Not surprisingly, people with disturbed sleep have higher rates of work absence due to sickness (Akerstedt et al., 2007). If you’re sick, resting will help your body fight the illness more efficiently.

Diabetes is a condition characterized by consistently elevated blood glucose levels. Normally when you eat, your blood glucose level increases. In response to this increased blood glucose level, your body releases insulin to help transport glucose into cells for use or storage, in turn lowering your blood glucose level. If you lack sufficient sleep, however, your body’s tolerance for glucose in the blood increases and less insulin is released to transport glucose into your cells. This decreased clearance of glucose from the blood means that your blood sugar remains higher longer, and this is a risk factor for diabetes. Thus, chronic sleep deprivation is linked with a higher risk of developing type 2 diabetes (U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2011; U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2017).

Lack of sleep is also associated with increased risk for heart disease. This is because the heart and vascular system won’t get sufficient rest. Blood pressure and heart rate drop by about 10% during sleep, and this gives the heart and vascular system a break. If you’re sleep-deprived, however, your blood pressure and heart rate stay elevated not only that night but also the next day. Lack of sleep also puts the body under stress the following day, thereby increasing the release of stress hormones like cortisol and adrenaline. High levels of these hormones can prevent the typical drop in blood pressure during sleep that night. A continuous elevation of blood pressure—also known as hypertension—is a primary risk factor for heart disease. Stress and poor sleep contribute to one another, forming a cycle (U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2011; U.S. Department of Health and Human Services, National Heart, Lung, and Blood Institute, 2017).

A study among college students reporting an average of seven to eight hours of sleep per night found that sleep quality was better related to measures of health, wellbeing, and sleepiness than was sleep quantity. Poor sleep quality was correlated not only with increased levels of sleepiness but also increased physical health complaints, feelings of anxiety, depression, anger, fatigue, and confusion, as well as a decrease in positive outlook and satisfaction with life (Pilcher et al., 1997).

People who sleep less may gravitate toward foods that are higher in calories and carbohydrates—for quick energy (Spiegel et al., 2004). It’s believed that this is because during sleep the body produces more leptin, an appetite-suppressing hormone, and less ghrelin, an appetite-stimulating hormone (Gutierrez & Willoughby, 2010). These hormones help regulate appetite while you sleep and while you are awake.