Yes, there is truth to this old saying by Benjamin Franklin. We were meant to get up with the light of dawn and to go to sleep at nightfall, our hormone levels adjusting to the rise and fall of daylight around us. Now, in our modern world we can fool our hormonal system with artificial light, which has a big impact on our health. Staying up late with bright lights shining in our eyes keeps our stress hormone cortisol high when it should be diminishing, and suppresses our sleep hormone melatonin, when it should be rising, which has an impact on our ability to deal with stress, lose weight, physically and psychologically repair our tissues, feel rested and be ready for the new day. So, try to get to sleep in a very dark room by 10pm, and marvel at how much better you feel!
A recent survey of university students in Utah has found that students who habitually go to bed late and sleep late the next day have lower grade point averages (GPAs) than students with early-to-bed and early-to-rise sleeping habits.
Researchers at Brigham Young University in Provo surveyed 184 of the school's freshmen and found that the later students slept in the morning, the lower their grades tended to be.
Out of all the factors studied, weekday and weekend wakeup times had the strongest association with students' GPAs. Each hour over the average that students slept in on weekdays was associated with a 0.13-point drop on the GPA (0.0-4.0 scale). A similar correlation was found for hours spent in bed on weekends, when many students catch up on sleep.
Eating breakfast each morning was also associated with higher grades, while having a night job was associated with lower grades.
Although many would automatically assume that alcohol consumption was a possible culprit for the connection between late sleeping and poor grades, since heavy drinking has been shown to damage academic performance. But the researchers point out that Brigham Young University is a dry campus where students sign agreements not to drink. "Alcohol-consumption behavior sufficient to cause morning hangover would be difficult to hide in the monitored residence halls of this university," the authors wrote in the report.
Journal of American College Health 2000; 49: 125-130
Here is strong evidence backing my "early to bed - early to rise" recommendations. The reason that this is so important is that our body's systems are tied to the natural circadian rhythms of the earth. Our bodys, particularly the adrenal glands, also do most of their healing during the early part of the night. Going to bed early is even more important in the winter when the sun sets earlier.
In April of this year, the Institute of Medicine issued a report that confirmed definite links between sleep deprivation and increased risks of hypertension, diabetes, obesity, depression, heart attack and stroke.
Some scientists are also investigating connections between insufficient sleep and depressed immune function.
Sleep can work to activate or inhibit hormone production in the hypothalamus, which is the part of the brain that gives the body signals regarding when to adjust temperature, blood pressure, digestive secretions and immune activity. Insufficient sleep also inhibits the pancreas from producing insulin, the hormone required for the digestion of glucose.
A groundbreaking 1999 study showed that after six days on only four hours of sleep, healthy volunteers would fall into a pre-diabetic state. Sleep also gives the heart a chance to slow down, and those who less than six hours a night have as much as a 66 percent greater prevalence of hypertension.
The largest study of sleep duration and mortality followed over one million participants for six years. Those who slept about seven hours had the highest survival rate, and those who slept less than 4.5 hours had the worst. Nine hours of sleep or more each night was also associated with a higher mortality risk, however.
In general, a good night's sleep seems to be as important to good health as a nutritious diet and regular exercise. Experts tend to agree that the majority of people require about eight hours of sleep each night.
However, roughly 40 percent of Americans get fewer than seven hours of sleep on weekdays, and 71 percent get fewer than eight hours of sleep. As a result, most Americans accumulate two full weeks of "sleep debt" each year. The two main causes for sleep debt were long work hours and long commutes.
Human beings sleep through one-third of their lives, yet why we sleep is one of the biggest unanswered questions of science. In the fascinating article from 60 Minutes, linked below, Lesley Stahl explores all of the latest scientific findings about the reasons for -- and functions of -- sleep.
Here is a sampling of what she found after talking with sleep researchers from across the United States: