We’ve always known that sleep is good for your brain, but new research from the University of Rochester provides the first direct evidence for why your brain cells need you to sleep (and sleep the right way—more on that later). The study found that when you sleep your brain removes toxic proteins from its neurons that are by-products of neural activity when you’re awake. Unfortunately, your brain can remove them adequately only while you’re asleep. So when you don’t get enough sleep, the toxic proteins remain in your brain cells, wreaking havoc by impairing your ability to think—something no amount of caffeine can fix.
Skipping sleep impairs your brain function across the board. It slows your ability to process information and problem solve, kills your creativity, and catapults your stress levels and emotional reactivity.
A good night’s sleep serves as a buffer during what can be a very stressful period of study. Sleep is the body’s way to recover and rebuild what was broken down during the day. How deep you sleep seems to be more important than how long. The optimal amount of sleep is between four and eleven hours.
Sleep and stress
Stress affects our sleep in several ways. For one, it increases the metabolism and with it the body temperature, and since a drop in body temperature is needed to sleep, this can make it difficult to fall asleep. Any sleep obtained is insufficiently deep and we are more easily woken. A knock-on effect is that we then become anxious about insomnia, which impoverishes the sleep we do get even more and reduces our tolerance to stress.
What Sleep Deprivation Does to Your Health
Sleep deprivation is linked to a variety of serious health problems, including heart attack, stroke, type 2 diabetes, and obesity. It stresses you out because your body overproduces the stress hormone cortisol when it’s sleep deprived. While excess cortisol has a host of negative health effects that come from the havoc it wreaks on your immune system, it also makes you look older, because cortisol breaks down skin collagen, the protein that keeps skin smooth and elastic. In men specifically, not sleeping enough reduces testosterone levels and lowers sperm count.
Too many studies to list have shown that people who get enough sleep live longer, healthier lives, but I understand that sometimes this isn’t motivation enough. So consider this—not sleeping enough makes you fat. Sleep deprivation compromises your body’s ability to metabolize carbohydrates and control food intake. When you sleep less you eat more and have more difficulty burning the calories you consume. Sleep deprivation makes you hungrier by increasing the appetite-stimulating hormone ghrelin and makes it harder for you to get full by reducing levels of the satiety-inducing hormone leptin. People who sleep less than 6 hours a night are 30% more likely to become obese than those who sleep 7 to 9 hours a night.
Tips for getting a good night’s sleep
Here is some general advice about sleeping better. You can also get some practical tools for how to tackle sleep problems using self-help CBT from Marie Söderström’s book Sömn, sov bättre med kognitiv beteendeterapi (in Swedish) which is based on the latest findings on sleep and stress.
- A cool (14-18°), dark, quiet room with a good bed. But don’t forget a warm duvet if the room is too cold.
- Avoid coffee, tea, coke, energy drinks and alcohol six hours before going to bed. Alcohol might induce sleep, but the quality of the sleep you get is worse.
- If you’re hungry, eat a light snack. Hunger induces an instinctive need to search for food, which boosts levels of adrenalin and noradrenalin, making us alert and more liable to wake in the middle of the night feeling ravenous.
- Regular times and daylight in the morning. The brain loves routine so that it can adjust itself to coming needs in good time. If you have regular sleeping times, your brain knows what to expect and can wind down sufficiently in time for sleep.
- Physical activity (low-intensity exercise), ideally every day. A walk or a run is enough, ideally no later than two hours before going to bed.
- Avoid naps and don’t sleep for too long. Napping is the subject of much debate at the moment, and it seems that naps are so effective that they can even be “abused”. If you have slept badly, have insomnia or find yourself in an energy-demanding environment, a 20-minute power nap can help you to recover and reduce your night-time sleep requirement. However, if you are already getting a good night’s sleep, napping can affect the quality of the coming night’s sleep.
- Wind down before going to bed. Winding down helps to prepare the brain for sleep. This is particularly important to teach children so that they can develop good sleeping habits for the future. It’s more effective to read a story or do some other low-intensity activity than to simple, yank the child away from whatever he or she is doing and dragging them to bed. It’s important for children to learn to associate sleep with something pleasurable. A good way to wind down is to do some kind of breathing or relaxation exercise.When we breathe slower and relax, the body cools, a lower body temperature being essential to getting any sleep in the first place. The “eye relaxation” exercise is a good one to try.
- Bedtime rituals. Bedtime rituals can also signal to the brain that it’s time to prepare for sleep. Teeth brushing is a classic such ritual, as is the donning of pyjamas. Or you might have a glass of warm milk or a light sandwich, or listen to some relaxing music.
- Take a nice hot bath an hour or so before going to bed. A nice hot bath is soothing and stimulates the release of the hormone oxytocin, which induces a sense of relaxation and calm. It also raises the body temperature, so that when we step out and cool off, the body temperature drops more quickly and makes us feel sleepy.
- Write a to-do list before going to sleep and when waking up. It’s all too easy for us to worry about the day ahead and to lose sleep over it. So it can be a good idea to keep a pad of paper and a pen on your bedside table so that you can jot down everything you have to remember the following day instead of activating the brain by trying to remember it all and worrying about forgetting something.
- Don’t go to bed if you’re not feeling tired. This is the golden rule! It’s important for the brain to look forward to sleep, but if we go to bed too often without feeling sleepy, sleep easily becomes associated with feelings of inconvenience. If you can’t fall asleep after 20 minutes or so, get up and do some low-intensity activity until you start to feel drowsy. A good tip is to do something boring, like read an old annual report or solve a crossword.
Finally, rest assured that if you miss one or more nights’ sleep your body will make up for it by sleeping “better” when you finally do get some sleep. Sleep is a reflex and sooner or later it will come
More info. : Healthwatch – On sleep.
Karolinska Institute in Stockholm