Did the change to Daylight Savings Time throw you for a loop? I saw a lot of yawns around our water cooler. Even this one-hour time change reminds us how important our sleep cycle is, and how easily it is disrupted.
Sleep is controlled by our circadian rhythm, or internal daily biological clock, which dictates recurring physical and mental changes in our bodies throughout the day, including sleepiness. This “clock” is actually a pair of pinhead-sized brain structures located in the hypothalamus. The clock can be reset based on sunlight and other external cues, including alarm clocks. But when the time suddenly changes, either through travel or daylight savings time, it takes those tiny brain structures a few days to catch up to the new schedule.
No big deal, right? But good regular sleep is key to our well being. Human beings do not adapt to getting less sleep than they need, so the “sleep debt” has to be paid off, often on weekends by sleeping in. Too little sleep leads to drowsiness, irritability, difficulty concentrating, impaired memory and physical performance, and a depressed immune system. Sleep-deprived people perform as badly, or worse, on a driving simulator or hand-eye coordination tasks as intoxicated ones. When the sleep debt gets big enough, it can cause hallucinations and psychosis. Prolonged severe sleep deprivation can even lead to death.
In the modern world of electric lights, TV, computers, and cell phones, most of us do not get enough zzzzzs. A common myth is that we need less sleep as we age, but actually our needs don’t change much unless we are pregnant or sick, when our need increases. What does happen with age is that our sleep patterns change and we tend to wake more easily and have more trouble falling back asleep. Short naps can be helpful, but more than 30 minutes daytime sleep can disrupt the circadian rhythm and create more difficulty sleeping that night.
So how much sleep do we need? Most adults require 7-8 hours of sleep a night, with the rare individual needing as little as 5 or as much as 10 hours per night. Experts say that if you feel drowsy during the day, you probably haven't had enough sleep. If you routinely fall asleep within 5 minutes of lying down, you probably have severe sleep deprivation, possibly even a sleep disorder. But each person needs to check in honestly with his or her own body to determine what is enough sleep.
Tips for a good night’s sleep include:
1. Setting a regular sleep and wake schedule and sticking to it even on weekends.
2. Exercise 20-30 minutes per day, preferably at least 5 hours before bedtime.
3. Avoid caffeine, nicotine, and alcohol, especially close to bedtime.
4. Relax for at least 30 minutes before bed – try a bath, a book, or warm milk.
5. Get an hour of morning sunlight to keep your internal clock on time.
And Daylight Savings Time? Next time try going to bed 30 minutes earlier for a couple days leading up to the change.
- Rebecca Taggart
Rebecca Taggart is a San Francisco yoga instructor.