Most people know that not getting enough sleep can pack a punch on physical and mental wellbeing. This is true not only in the day or days following a night of acute sleep deprivation, but it’s especially true over the long term. Chronic, low-grade lack of sleep can take a serious toll on our health. More and more research has come in to suggest that sleep is not at all a passive act — it’s an active act, so to speak, and the brain is carrying out extraordinarily important processes during sleep.
Chronic, low-grade lack of sleep can take a serious toll on our health.
Many neurons (brain cells) continue to fire during sleep, hammering down the new information we’ve learned during the day, consolidating memories, and regulating body functions. In fact, lack of sleep has been shown to increase our risk for heart attack and stroke, and it can significantly suppress immune function and resistance.
The latest research is showing that sleep plays even bigger roles in weight and metabolism, brain function, and even sexual function than was previously thought. And, perhaps not surprisingly, it’s just as important in kids and babies as it is in adults. This article will outline some the latest sleep research, which is uncovering some exciting connections. We’ll also offer some tips on how to catch some more zzz’s if you’re not getting enough — and most people aren’t.
Men who were deprived of sleep had slower metabolisms: that is, their bodies burned fewer calories while at rest (up to 20% in some cases) than well-rested peers.
Now, a new study shows that loss of sleep actually slows down your metabolism, which can lead to weight gain. College men got either a full night’s sleep or were deprived of sleep for a 24-hour period. Their hormone levels, energy expenditure, and eating habits were all measured the next day. Men who were deprived of sleep had slower metabolisms: that is, their bodies burned fewer calories while at rest (up to 20% in some cases) than well-rested peers. The levels of hunger hormones, stress hormones, and blood sugar levels were all higher in the sleep-deprived men. The authors conclude that these changes in metabolism may be the missing link between sleep deprivation and obesity that prior studies have found.
While researchers are hashing out all the links between sleep, metabolism, hormone levels, and weight, it’s a good idea to watch your calorie intake when you are sleep-deprived — getting enough sleep in the first place goes without saying.
Researchers calculated that the loss in brain function linked to too much or too little sleep was the equivalent of being 4-7 years older than a well-rested brain.
Other studies have found that loss of sleep affects our ability to make quick, gut-level decisions that involve the rapid processing of outside information. The effect is pronounced enough, say the authors, that lack of sleep could affect the outcome of split-second life-or-death decisions in people like firefighters or policemen.
Getting too little – or too much – sleep has also been linked to worse performance on cognitive tests measuring verbal and reasoning abilities. A study followed middle-aged people for five years, tracking their sleep habits and cognitive prowess. Sleeping for less than six or more than eight hours was linked to deficits in cognition. Specifically, people whose average amount of sleep changed over time (becoming either longer or shorter than it had been) had more problems with cognition. The effects were so strong that the researchers calculated that the loss in brain function linked to too much or too little sleep was the equivalent of being 4-7 years older than a well-rested brain.
Sleep deprivation may also lead one to make poor economic decisions. In one study, people who were sleep-deprived made riskier financial choices in a decision-making task than well-rested participants. Even more, the parts of their brains associated with positive outcomes were more active, and those associated with negative outcomes were less active, implying that people are slightly more deluded about their decisions when they are sleep-deprived.
Sleep disorders like obstructive sleep apnea (OSA) affect the sleep of millions of Americans. And OSA may have a connection to a disorder that you would never think of: erectile dysfunction (ED) in men. In one new study, men who had ED suffered from OSA twice as much as those without. And the more severe the ED, the more likely the men were to have OSA. This study did not show a cause-and-effect relationship, however, so the exact nature of the nature of the relationship is still unclear. But earlier studies have arrived at similar findings: one large review found that sleep disorders like sleep apnea and insomnia were linked to ED, and that ED might actually be helped by treating the person’s sleep disorder.
Men who had ED suffered from OSA (obstructive sleep apnea) twice as much as those without. And the more severe the ED, the more likely the men were to have OSA.
Even studies in mice have found that after being subjected to oxygen deprivation during sleep (which is similar to what happens in OSA), mice experienced declines in erections and were less interested in sex than other male mice. The researchers in this study also discovered that a reduction in blood vessel function may be behind the connection (since erections rely on increased blood flow). But again, the relationship between sleep and sexual function (in men) is still somewhat foggy and more research is being done to understand it.
Though they may not always believe it, children and babies need their sleep, too. One reason, according to a new study, is that sleep is linked to growth spurts in infants. Bursts of increased sleep, where infants slept much more than usual for a couple of days (up to several hours, both from increased nap and night sleep) were linked to growth spurts, periods of concentrated growth. The sleep bursts often preceded the growth spurts by about 48 hours, serving almost as a signal that an increased period of growth was about to occur. The connection may exist because growth hormone is secreted during sleep, but the exact mechanism is still unclear.
Each additional hour of sleep was also linked to a whopping 61% reduction in the odds of being overweight/obese by the time the kids were 7 years old.
Just as sleep is linked to metabolism and weight issues in adults, it plays a similar role in children. Researchers measured kids’ body mass index (BMI), activity levels, and the amount of fat and non-fat mass (i.e., muscle and bone) the kids carried around with them. They also tracked the kids’ sleep habits, and other lifestyle factors, from the time kids were 3 until they were 7 years old. They found that for every additional hour of sleep the kids got per night, their BMI was almost half a point lower than kids who slept less.
Each additional hour of sleep was also linked to a whopping 61% reduction in the odds of being overweight/obese by the time the kids were 7 years old. After the researchers teased apart the data, they learned that the changes in weight were indeed due to fat mass, rather than non-fat mass. They suggest that the effects observed here may be due to a couple of different factors. One is behavioral: if kids are awake more, they simply have more time to snack, even if they’re not hungry; additionally, fatigue during the day can make kids less likely to be active and burn off calories. The other mechanism is biological: changes in hormone levels brought on by lack of sleep may also cause kids to feel hungrier, suggest the researchers, just as with adults.
The NIH estimates that upwards of 60 million Americans experience sleep problems, either chronically or occasionally. How well you sleep during just one night can make or break your day, and as we’ve seen, chronic sleep problems have important long-term health implications for body and mind. The National Sleep Foundation offers some tips on optimizing your sleep so you’ll function your best.