Lack of Sleep’s Impact on the Body


Between long work hours, family and social commitments, screen time, and other factors, it can be difficult to find time for a proper night's sleep. Sound sleep may be even harder to come by if you have a sleep disorder or another medical condition.

The average adult needs between seven and nine hours (1) of sleep per night, yet recent reports have indicated that 34.8% (2) of people regularly sleep less than seven hours per night.

At some point or another, all of us have had to power through the sleepiness and grouchiness that arise after a night of short sleep. However, when these short nights start to accumulate over a longer period of time, it can become a larger problem. Sleep plays a vital role in our health (3), and growing evidence shows that chronic sleep deprivation may contribute to a variety of health problems.

Impairs Attention, Learning, and Memory

The effects of sleep deprivation on the brain are quite complex, and researchers are still working to untangle exactly why some processes seem to be more affected than others (4). So far, evidence suggests that sleep deprivation has a negative impact on memory (5), learning (6), attention span (7), and creativity. It also increases the likelihood of making risky decisions (8).

Sleep-deprived individuals may also experience microsleeps, which can be very dangerous while driving or doing other tasks that require concentration. Even more concerning, sleep loss may affect your performance without causing you to feel consciously sleepy, meaning you may not realize you're at a higher risk of accidents. Sleep deprivation is considered to be a major contributor to work-related injuries, car accidents, and falls in elderly people.

Weakens Your Immune System

Getting proper sleep helps the body fight infection and improves your response to vaccines (9). By contrast, poor sleep sets off a stress response that causes elevated inflammation markers (10), including higher white blood cell counts (11) and altered levels of the stress hormone cortisol (12). Long-term sleep loss also lowers levels of "good" cholesterol (13). Over time, these changes have been associated with a higher risk of developing chronic conditions such as type 2 diabetes, high blood pressure, and obesity.

Contributes to Weight Gain and Obesity

Losing sleep contributes to weight gain through a number of mechanisms. The most straightforward effect is that it leaves us more time to eat (14), since we spend more time awake. After a night of short sleep, the body also lowers our metabolism to save energy, which makes it more difficult to burn off the extra calories.

Sleep deprivation directly affects our hormone levels by lowering levels of leptin, an appetite suppressant. Sleep deprivation also boosts levels of ghrelin and endocannabinoids, hormones that stimulate appetite and encourage us to seek out high-calorie treats. Additionally, disrupted sleep interferes with the release of growth hormone (15), which is important for regulating metabolism and ensuring a healthy balance of muscle and fat.

Finally, sleep loss lowers sensitivity to insulin, interfering with glucose metabolism and contributing to the development of type 2 diabetes.

Raises the Risk of Heart Disease

Extended periods of sleep deprivation can raise the risk of heart disease. Blood pressure naturally fluctuates throughout the day and dips during the night while we are asleep. Interfering with sleep interrupts this cycle and may cause high blood pressure and premature stiffening of the arteries (16), which are risk factors for coronary heart disease, heart attack, and stroke.

Repetitive nighttime awakenings fragment sleep and may put people with obstructive sleep apnea especially at risk for heart disease.

Causes Mood Changes

If you've ever gone short on sleep, you'll know that the next day often brings irritability and mood swings (17). Sleep is an essential time for the brain to process emotional memories. Researchers believe that when this process is disrupted, we may suffer from blunted empathy (18) and be more likely to focus on negative memories (19).

Ample evidence indicates that long-term sleep deprivation can cause symptoms of anxiety and depression (20), even for people with no preexisting mental health conditions. Sleep loss likely shares a bidirectional relationship (21) with mood disorders. This means that mood disorders affect sleep quality, and poor sleep affects the severity of mood disorders.

Lowers Your Pain Threshold

Both short sleep and poor sleep quality can lower our pain threshold (22). This has special significance for people with chronic pain disorders (23) such as fibromyalgia because they may find it harder to cope with symptoms when they don't get enough sleep. Unfortunately, those with chronic pain may also have a difficult time sleeping at night, creating a negative feedback cycle (24).

Lowers Sex Drive

Sleep deprivation interferes with sexual performance for both men and women. For men, disrupted sleep, particularly in the second half of the night, lowers testosterone levels (25) and may contribute to sexual dysfunction. For women, sleep loss triggers feelings of anxiety (26) and lowers libido (27).

Affects Exercise Performance

There's a reason why professional athletes prioritize sleep. In addition to sapping energy levels (28), sleep deprivation can worsen decision-making, accuracy, reaction times, strength, and endurance (29). Many professional athletes aim to get even more sleep than usual the night before an important competition in the hopes that this can give them an extra performance boost.

The effects of sleep deprivation on the body and brain are highly complex. In many cases it's difficult to say whether sleep loss causes certain symptoms or whether those symptoms interfere with sleep. However, if you find you're not feeling your best, tackling sleep problems might be the key to regaining control of your health. Following healthy sleep hygiene habits, keeping a consistent sleep schedule, addressing sleep disorders, and setting aside time to make up your sleep debt can help set you up to be more resilient and feel better overall.



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