As many of you have noticed (and lamented), sleep is a big part of the Transformation Challenge. But sleep doesn’t just impact how hard it is to get out of bed or how much coffee you need to survive the day, it can also affect your food choices, sports performance, and long term health.
Sleep occurs in two parts, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep makes up about 75% of sleep time and consists of four stages. Stages 1 and 2 are the beginnings of sleep, when your start breathing more irregularly and begin to disengage from your surroundings. Stages 3 and 4 are the parts of the sleep cycle where the most recovery occurs, as breathing slows, tissues are repaired, energy is restored, and important hormones are released. REM sleep makes up the other 25% of sleep time, usually happening 90 minutes after you fall asleep and recurring every 90 minutes. During REM sleep, energy is provided to the brain and body, the brain is active – this is the part of sleep where dreaming happens – while the body becomes immobile as muscles are turned off.
Sleep and Weight
In the medical world it’s been widely accepted that people who sleep less are more likely to be overweight. Research has found that people who sleep enough eat on average 200-500 fewer calories than people who don’t. But they didn’t always know why. But now TWO studies that used magnetic resonance imaging (MRI) to look at brain activity found two different ways that sleep may influence what you eat. In both studies, people were assessed after getting enough sleep and after a period of disrupted sleep and in both they were shown images of healthy and unhealthy foods while in the scanner. One study found that the part of the brain that tells us something is rewarding was more active when looking at unhealthy foods after sleeping poorly than it was after sleeping enough. In the other study people who didn’t get enough sleep showed less activity in the frontal lobe, or the part of the brain responsible for making decisions. Basically what these studies tell us is that when you don’t get enough sleep, unhealthier foods look more appealing and at the same time your ability to resist that food may be diminished.
Sleep and Hunger
Lack of sleep doesn’t just make you crave uhealthier food, it also influences important hormones that control hunger. These two hormones are leptin and ghrelin. Leptin is stored in fat cells,and low levels of it tell the body you are starving and need to eat more food. Ghrelin is produced by the stomach and stimulates your appetite, again making you want to eat more. Ideally, you’d want to have higher leptin levels and lower ghrelin levels. However research has found that people who sleep less than 5 hours per night on average had lower levels of leptin and higher levels of ghrelin than people who sleep more. This means sleeping less = bigger appetite, on top of any appetite increase you may have from exercising.
Sleep and Sports Performance
Last month ESPN published a commentary article calling sleep the new “magic pill”. This claim was based on research at Stanford, which manipulated sleep habits of 11 basketball players and found that when they increased their sleep they sprinted faster, felt better, and saw improvement in three-point shooting and free throw percentages. This is because during deep sleep, the body releases growth hormones that stimulate the building and recovery of bone and muscle. In addition, you need adequate sleep to have enough energy and good cognitive function, which means more alertness and coordination. Research in Europe a few years ago found that sleep 6 or less hours per night can have the same effects on coordination as drinking alcohol. This can really make a difference when you’re working on technical movements (think rowing, olympic lifts, kipping pull ups).
Experts say that teens need 8 ½ to 9 ½ hours of sleep per night and adults need 7-9 hours to be well rested.
A few strategies to improve sleep It’s not only important to get enough sleep, you need good quality, uninterrupted sleep too. Here are a few things you can do to help:
- Sleep in a dark room
- Avoid LCD screens (TV, computer) 15-30 minutes before bed
- Sleep in a colder temperature
- Avoid caffeine 4-6 hours before bed
- Avoid drinking excess water before bed (getting up to use the bathroom will interrupt sleep)