Sleep is vastly undervalued. We like to “burn the midnight oil,” and then brag about it. For medical interns, working long hours with little sleep is almost a rite of passage. World leaders and corporate titans take pride in declaring their ability to function round the clock. They are all sadly mistaken.
Human adults need 7 to 8 hours of sleep every night. The brain, the rest of the body, our metabolism, our mood: All of these are heavily dependent on adequate sleep to function properly.
Sleep and obesity
The links between sleep and body weight have only recently received focused research attention. There is little doubt now that sustained sleep deprivation predisposes a person to obesity by affecting both appetite and activity.
Sleep and hunger hormones
Leptin and ghrelin are hormones which regulate hunger, satiety and appetite. Leptin is the satiety hormone. It is secreted by fat cells, and sends a signal to the brain that you are full. The brain then suppresses your appetite, and hopefully you stop eating at that point. But sleep deprivation interferes with this mechanism. It has been shown that reducing sleep time to 4 hours a night for 6 days significantly reduces the blood levels of leptin, so you do not get the signal to cut down on food intake. Appetite is increased, even though the body may not need extra calories.
Ghrelin, by contrast, is the ‘hunger hormone’ produced by the stomach. It increases appetite. Sleep reduction to just 4 hours a night for 2 days causes a rise in ghrelin levels, and an increase in appetite.
Thus loss of adequate sleep time interferes with the ability of the body to regulate appetite based on its caloric needs.
Sleep and activity
Even one night of partial sleep deprivation has been shown to be potentially harmful. Otherwise healthy people subjected to sleep loss have reduced activity levels the following day. Sleeping for fewer than 6 hours a night on a regular basis leads to significantly lower activity levels.
So loss of sleep causes increased caloric intake and reduced energy expenditure. This combination explains the link between sleep deprivation and obesity.
Because of the factors mentioned above, sleep deprivation interferes with the ability of a low calorie diet to successfully induce weight loss.
Clearly, if you want to lose weight and keep it off long-term, your odds will increase if you sleep regularly for 8 hours a night.
Sleep and cognition
Research clearly reflects that sleep is important for memory, focus, attention, and cognition. Sleep deprivation adversely affects all of these important skills.
But life is hectic. Who has time to sleep?
It is easy to give advice about sleep, but modern life intervenes. So is all lost? Not necessarily.
It is important to follow certain principles of sleep hygiene to make the best of the hours of sleep you do get. Try to keep your sleeping area dark, slightly on the cooler side, and free from distractions such as TV, computers, cell phones, etc.
You should try and maintain as regular a schedule of sleeping as possible, with fairly fixed hours of going to bed and waking up. Obviously, this is easier said than done, but it is a goal worth striving for.
Alcohol and caffeine can interfere with sleep, and one should avoid their use for several hours before bedtime.
People who exercise regularly improve their sleep quality. However, do not exercise for about 3 hours before you plan to go to bed.
Can you make up for lost sleep?
Well, napping has been tried. This can improve your mood and also alertness level in the short term. Naps can improve performance, but it is unlikely that a nap will make up for poor quality sleep, or for long-term sleep deprivation.
It is also unclear whether napping can reverse the metabolic effects of sleep deprivation, particularly the effects on weight gain.
Also, if you do nap, it appears that 10 minutes produce the most benefit, according to a study in Sleep. Napping for more than 30 minutes may end up making you feel groggy.
There is also a suggestion that long naps can interfere with night-time sleep, affecting both its duration and quality. The same problem can occur if you nap late in the afternoon or evening, closer to bed time.
Pay off sleep debt?
It has been suggested that you can make up for an accumulated sleep deficit by sleeping longer on weekends, or during a vacation when you can set your own schedule, and get extra sleep each night, waking up naturally in the mornings without an alarm.
Research shows that some effects of sleep debt, such as daytime sleepiness, can be mitigated by this method. However, impaired attention levels caused by sleep deprivation may not improve with catch-up sleep.
There is a recent study showing that we might not be able to counter the effects of chronic sleep deprivation. This is a study in mice, but it should raise concern. Penn Medicine researchers published a study in The Journal of Neuroscience in March 2014, showing the effects of sleep deprivation in mice. They found that after short-term sleep deprivation, mice brains were able to change the levels of an important protein to protect brain cells from injury.
However, if the sleep deprivation was prolonged, this protective response did not kick in, and mice brain cells started to die. The locus coeruleus is a brain region important for alertness and cognition. With long-term sleep loss, mice lost 25% of the nerve cells in this brain region. And, as they say, death is permanent.
So get enough sleep, starting tonight. Your brain will thank you, and your body will get lighter.
Enjoyed this article-it is so true about how sleep deprivation effects people in the work place, this is being seen way to often.
Yes, Gloria, work performance is severely affected. The world and modern society are turning human beings into sleep deprived zombies. Lots of accidents occur due to sleepy drivers. We need to develop better sleep hygiene.
I always think about you Dr. Harsh when someone asks me how many hours sleep you should get each night. I always remember you telling me 8 hours, no less. I find it hard to sleep that much as i get older but I know it is important. thanks for this valuable information.
I am glad at least somebody remebers what I told them!