After many years of research, science still struggles to explain why we need to spend 1/3 of our life sleeping. And why we feel bad if we don’t.
Think about it. This means that on average we sleep 25 years of our lives! No wonder people have tried to do with as little sleep as possible to extend the number of “useful” hours in the day.
WHY IS SLEEP IMPORTANT?
Research over the last few decades hints at the necessity of sleep. A recent article
by Robert Stickgold reviews some of the most relevant historical studies. One famous study in an animal model speaks to the absolute necessity of sleep. In this 1989 study of sleep in rats, rats were kept awake for one month after which they died.
Other research in humans, as Dr. Stickgold points out, sleep appears to be supportive but not an absolute necessity for many health-related functions including immunity, hormonal balance and psychologic health and memory. For example, a study from 2003 looked at immune response to hepatitis A vaccine exposure and found that sleep, on the night of the exposure, resulted in a 97% increase in the development of protective antibodies compared to people without sleep. Another study found poor sleep (less than 4 hours) resulted in a decrease in appetite suppressing hormones and increase in appetite stimulant hormones. These findings generally correlate with other studies showing weight increase with poor sleep.
A 2006 study suggests that many of us have a significantly better memory for negative words while sleep deprived. Could it be then at the end of the day you are more likely to have negative memory of the day?
Sleep also appears to directly correlate with the brains ability to remove neurotoxins. Poor sleep also appears to be a risk factor for depression, and diabetes.
The bottom line, important functions occur during sleep so maybe that third of our life we spend in it, is not wasted after all.
By: Eric Dec, MD
Robert Stickgold, “Sleep on it”. Scientific American, October 2015.