Blog | Tuesday, May 7, 2013

10 surprising facts about sleep

I think we all know that sleep is not only beneficial for good health, but lack of sleep can lead to a number of serious disorders and diseases. Here are 10 sleep facts that may surprise you:

1. When we are awake our brain cells produce adenosine as a byproduct. The build-up of adenosine in the brain is thought to be one factor that leads to our perception of being tired. (Incidentally, this feeling is counteracted by the use of caffeine, which blocks the actions of adenosine in the brain and keeps us alert.)

2. Older adults need about the same amount of sleep as younger adults (7-9 hours) but seniors go to bed earlier and wake up earlier than when they were younger.

3. We dream only during REM (Rapid Eye Movement) sleep but get the deepest sleep during non-REM cycles.

4. It is not only important to get sleep to learn, but it is also important to get good sleep after we learn something new to process and retain that knowledge.

5. Insomnia is the most common sleep disorder after age 60. People with insomnia have trouble falling asleep and staying asleep.

6. Major restorative functions in the body like muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly, or in some cases only, during sleep.

7. Hitting the snooze button makes getting out of bed more challenging than simply getting up with the first alarm, because a few more minutes of shuteye causes the brain to enter a deeper sleep cycle.

8. Losing just a few hours of sleep a week, similar to the effects of jet lag or cramming for final exams, can lead to almost immediate weight gain. The good news is getting extra sleep can cause those pounds to shed.

9. Recent studies show that daylight savings time increases risk of getting into an accident by 11% and your risk of myocardial infarction by up to 10% in the three weeks after the change. To get used to the change, experts recommend soaking in the sun in the evening with the later sunset, getting some exercise and going to be earlier.

10. Residents in the Southern states experience the most sleep disturbances and daytime sleepiness, according to a new "sleep map" that outlines how geography can influence sleep patterns. Residents of the West Coast report better sleep. Check out the sleep map here.

This post originally appeared at Everything Health. Toni Brayer, MD, FACP, is an ACP Internist editorial board member who blogs at EverythingHealth, designed to address the rapid changes in science, medicine, health and healing in the 21st Century.