The consequences of sleep deprivation — why sleep matters

Sleep is one of the most fundamental needs of every human being. But it’s also one of the things we tend to put on the back burner. A good night’s sleep isn’t just important for feeling rested and energetic the next day — it has a major impact on our overall health and well-being.

When we don’t get enough sleep, the consequences can be serious. Let’s dig into what sleep deprivation actually does, and why sleep is so important.

Impaired memory and learning

Among the most well-documented consequences of sleep deprivation is a decline in memory and the ability to learn. Extensive research backs this up, including a study from the University of Turku, which found that both acute total sleep deprivation and chronic partial sleep deprivation have a negative effect on attention and cognition.^[1]

Researchers also point out that the effects can vary depending on the individual, and that there are differences in how people perform under sleep deprivation.

There may also be sex-based differences in how we respond to sleep loss. Women appear to handle prolonged wakefulness better than men in terms of cognitive performance, even though they recover more slowly physiologically. This research highlights how complex and individual our responses to sleep deprivation can be.

Higher risk of chronic disease

A lack of sleep can also raise the risk of a number of chronic conditions. Several studies have shown that prolonged sleep deprivation can lead to elevated blood pressure, diabetes, heart disease and even certain types of cancer.

Weakened immune system

While we sleep, the body produces and releases proteins called cytokines, which help fight infection and inflammation. Lack of sleep reduces cytokine production, which weakens the immune system and makes us more susceptible to illness.

A comprehensive meta-analysis from the University of Warwick, among others, gathered data from 16 studies involving more than 1.3 million participants, and concluded that sleep duration is a significant predictor of mortality.^[2]

The researchers found that short sleep duration was associated with a higher risk of death.

Mental health

Sleep is also important for our mental health. Chronic sleep deprivation has been linked to an increased risk of mental health conditions like depression and anxiety.

Sleep problems are also common among people with mental illness, creating a vicious cycle in which poor sleep can worsen mental health conditions, and those conditions can in turn worsen sleep.

Recovery and regeneration

Sleep is the body’s chance to repair itself. During the deeper sleep stages, tissue is rebuilt, growth hormone is released, and the brain processes the experiences of the day. Without enough sleep, all of those repair processes are cut short.

Productivity

An important consequence of sleep deprivation that often gets overlooked is its effect on productivity. This is especially relevant in our modern lives, where many people are juggling work and family. Research from an international group of researchers including the University of Johannesburg has examined this and turned up some concerning results.^[3]

The study focused on working mothers in Pakistan, a demographic that often experiences high levels of stress and sleep deprivation due to multiple obligations both at work and at home. Researchers found that sleep deprivation is positively correlated with stress, which in turn negatively affects performance at work.

The study shows how sleep deprivation can have a real, measurable cost — not just personally, but professionally as well.

Higher risk of accidents

Lack of sleep raises your risk of accidents. Sleep deprivation reduces attention and slows reaction time — particularly dangerous behind the wheel of a car or while operating machinery.

Several studies have shown that drowsiness behind the wheel can be just as dangerous as driving while intoxicated.

Disrupted hormonal balance

Sleep deprivation can also disrupt the body’s hormone balance. That can lead to a range of issues, including weight gain, lower libido and trouble with fertility. For example, the body produces less leptin (a hormone that signals fullness) and more ghrelin (a hormone that promotes hunger) when we don’t get enough sleep — which can lead to overeating and weight gain.

Frequently asked questions

How much sleep do I need?

This varies from person to person, but in general adults are recommended to get between 7 and 9 hours a night. Children and teenagers need even more, given that their bodies and brains are still growing.

What are some effective ways to combat sleep deprivation?

Establishing a consistent sleep schedule — going to bed and getting up at the same time every day — can help regulate your sleep pattern. Avoid caffeine and heavy meals close to bedtime. Making sure your bedroom is dark, quiet and cool also helps promote a good night’s sleep.

Can you make up for lost sleep?

While it’s possible to feel more rested after sleeping in following a period of sleep loss, research suggests that you can’t fully “make up” for lost sleep — particularly when it comes to its long-term effects on health. The best approach is to sleep enough on a regular basis, rather than trying to catch up at weekends.