Our genes determine how much sleep we need
Adults should get at least 7 hours a day of sleep (more for children and adolescents). What determines how long we sleep? Is it entirely up to us? Do the demands of school and work decide it? What role does genetics play? Evidence now suggests that our genes determine how much sleep we need.
Most people decide when we go to bed and when we get out of bed based on a number of factors. These include:
1. Work or school schedules
2. Time of TV programming
3. Use of televisions, computers, smart phones in bedrooms
4. Caffeine and alcohol intake
5. Hours that shops and grocery stores are open
6. Prescription and illegal drugs that affect sleep
7. Demands of family
8. Noise and light
9. Neighborhood crime
10. Our body’s inner schedule
How much of our sleep need is genetic?
Some people get less sleep than others do, some get more. 7 hours of sleep is enough for some, but others need 9 hours. In part, our genes determine this. In adults, 39% of sleep duration is genetic In children, 68% of sleep duration on weekends is genetic (but only 15% on school days).
Some people can withstand sleep deprivation better than others can. A third of people have major cognitive performance problems with moderate sleep loss. A third show problems that are not as severe. One-thirds of people deal with severe sleep loss with little change in performance. The same people show the same kind of response to sleep loss separated by long periods. Evidence suggests that this resilience to sleep loss is genetic. Interestingly, people who deal well with sleep loss do not necessarily report that they are not sleepy or fatigued. People who report not being very sleepy or fatigued with sleep loss do not necessarily perform well. Thus, there is often a disconnect between how we believe we are standing up to sleep deprivation, and how we are actually performing.
Sleep duration also affects other health functions, such as high blood pressure, blood sugar and weight. Insufficient sleep affects our health adversely. We should all strive to get enough sleep so we feel rested and our health does not suffer. However, some of us do function pretty well even with sleep deprivation. Others lose cognitive function and performance even with small amounts of sleep loss. People in general and health care professional in particular should be aware of that.