Obvious statement alert: Lack of sleep is becoming more and more common. Whether it’s due to a busy schedule, a stack of responsibilities, or your social life, chances are you aren’t getting the recommended six to eight hours of sleep per night. It’s easy to eventually just accept the routine grogginess. However, it’s important to take a look at the effects a lack of sleep has on the body. Read on for five areas that take a major hit when you’ve worked (or scrolled Instagram) through the night.
Your Appetite
Getting too little sleep can throw your health and hunger habits through a loop. This is because being deprived can wreak havoc on your hormones. “[There’s] a report we did showing that people who sleep six hours or fewer on average consume an additional 300-plus calories per day as a result,” says Chris Brantner, a certified sleep science coach and the founder of SleepZoo. “This is largely due to the fact that sleep deprivation causes an increase in levels of ghrelin, a hunger hormone, and a decrease in levels of leptin, a hormone that helps you feel full.”
Rachel Wong, certified lead sleep coach at Reverie, further explains, “Ghrelin tells your body when it should be hungry, while leptin signals to your body that you’ve eaten enough. A study at the University of Chicago found that operating on four or five hours of sleep decreased the concentrations of leptin and increased the levels of ghrelin, making you hungrier while feeling less full—the wrong combo in every way when you’re trying to get healthier.” This increase in appetite, coupled with the fogginess of no sleep, can negatively impact your willpower and lead to food choices you wouldn’t make otherwise.
Your Energy and Exercise Recovery
A well-known result of sleep deprivation is its effect on your workout the following day. “The fact is, you’re less likely to work out because you will have less energy and lessened willpower,” Brantner notes. When you barely have the energy to function normally, just the thought of running on the treadmill or doing heavy lifting can become majorly unappealing.
“Lack of sleep lowers your motivation. Many of us need every little nudge possible to get in that workout or reach for the apple instead of the cookie. When we don’t sleep, it’s like our inner drive gets sucker punched,” Wong says. “Lack of sleep really inhibits our vigilance—so you might stop early on your reps or skip your workout entirely when you’re running low on sleep.”
Less well-known, though, is the effect little sleep has on your workout from the day before. “Lack of sleep puts a damper on your prior day’s workout,” Wong explains. “While we sleep, our body makes essential repairs. This happens during slow-wave sleep, also known as deep sleep, in the first part of the night. During deep sleep, your body releases growth hormones, which can heal the tissues of muscles that have been worn down by your previous day’s exercise. When you miss out on sleep, your body wastes the gains from that day’s workout.” Like rest days, proper sleep is essential to the recovery process because, without it, your body can’t fully heal and rebuild muscle.
Your Digestive System
When you don’t get enough sleep, you also risk waking up bloated and uncomfortable. “When you are sleep-deprived, your body produces cortisol, a stress hormone. This can lead to bloating and constipation,” Brantner says. In other words, sleep deprivation messes up your cortisol secretion. This not only has the ability to create more stress in general but can also stress out your digestive system. It’s not a symptom that goes away after a couple hours either. The heightened cortisol release can actually take place as late as the next evening, which means the bloating could last all day. This discomfort may have the domino effect of a skipped workout or unhealthy food choices throughout the day.
Your Focus and Memory
It goes without saying that when you don’t get enough sleep, your brain doesn’t perform in top shape. What may come across as feeling foggy, though, is actually a bit more serious. “One study concluded that sleep deprivation actually disrupts your brain cells’ ability to communicate amongst each other,” Brantner says. “This leads to temporary mental lapses that can affect memory and perception. The study showed that sleep deprivation seemed to interfere with the ability of neurons to encode information, as well as translate visual input into conscious thought.” So a lack of sleep can prevent your brain from processing new memories, focusing, and receiving new information.
Another study from the Journal of Neuroscience found that sleep loss caused phagocytes (aka cells that engulf and absorb bacteria and other cells) in mice to go into overdrive. In short, when you lack sleep, your brain begins to experience lapses and eat away at itself. Yikes.
Your Heart Health
When it comes to heart health, people often overlook the importance of sleep. “Regardless of age, weight, or smoking habits, people who are sleep-deprived are at a higher risk for cardiovascular disease,” Brantner notes. “Studies suggest that people who get fewer than six hours of sleep per night are twice as likely to suffer a heart attack or stroke as people who get six to eight hours.” While “suggest” is the operative word here—and this has been shown to only take effect in those who have chronic sleep deprivation—the odds are still frightening.
“Consider what we’ve learned about sleep apnea,” he adds, touching on the sleep disorder in which breathing repeatedly stops and starts throughout the night. “The condition that causes people to wake frequently throughout the night can often lead to heart damage. You need deep sleep to allow the body to go into periods of lowered blood pressure and heart rate. This appears crucial for heart health.”
The Importance of Sleep
While on this topic, Wong made sure to point out how pivotal sleep is to a healthy lifestyle. “Sometimes we really want to get healthier, but we will start traveling down this ‘downward health spiral,’ as I like to think of it. We might skimp on sleep one night. Then, the next day, we don’t have the willpower to resist a doughnut (or two). Then we forgo the workout entirely because we just don’t feel like it. It starts this downward spiral of one thing leading to the other.” While this admittedly sounds bleak, the opposite is also true.
“On the flip side, you have this upward health spiral, too,” Wong continues. “You start working out, which makes you eat healthier, and you’re more tired when it’s bedtime. All of a sudden you find more balance in every part of wellness, not just one.”
Notice how sleep plays an integral part in both situations. “Sleep is often the catalyst for both. It often starts and compounds the downward cycle. But it can also be the easiest place to start when you’re trying to get healthier,” Wong says. “So for anyone trying to work out more, eat healthier, or just feel better overall, don’t discount sleep in the health equation. It might just be the most important piece!”