Sleep Debt: What Are Its Effects and Can You Repay It?

written by / March 11, 2020
Sleep Debt - Featured

Sleep debt can have a major negative impact on a person’s health, concentration, and ability to complete certain daily activities. About one-third of the planet’s inhabitants have had sleep problems at least once, and 10%–15% of them suffer from chronic insomnia, which leads to this physical debt. If you don’t want to become another of these negative statistics, it’s a good idea to know what signs mean you aren’t getting sufficient sleep and how to prevent this from causing harm to your body. 

Is Sleep Debt a Real Thing?

This type of debt is mutually connected with and caused by regularly not getting enough sleep. When this becomes prolonged and chronic, it leads to a problematic cumulative loss of sleep. However, the more you get less sleep than you need, it’s expected that the debt will grow more significant over time.

Ongoing sleep restriction is related to the accumulation of sleep loss. However, sleep quantity fluctuates with seasonal and social changes. Many people living in northern regions get more sleep during the darker months. But this logically shifts to sleeping less in the summer months. It was also demonstrated in several studies that boredom, isolation, and other negative social factors could increase the drive for sleep. This shows us that the known sleep debt definition doesn’t rely on the individual need for sleep but is instead determined by multiple factors.

We also have to take into account how the human body’s requirements for sleep are more flexible than some assume. One of the reasons for this is that shifts occur naturally in sleep cycles as part of the circadian clock. In line with this, it’s suggested that people evaluate and “repay” their accumulated lost sleep as often as possible. When this balance is impaired for an extended period, the lost sleep becomes a bigger concern.

So exactly what is sleep debt? While experts disagree on the precise details, it’s well known that insufficient sleep can make you tired, grumpy, and prone to illness and accidents. Furthermore, based on the knowledge that an accumulated loss of sleep adversely influences our mood and cognitive performance, many experts believe that this condition becoming chronic and long-term is a public health problem with physical, social, and economic consequences. Interestingly, some countries are more deprived of sleep than others.

Can You Die from Lack of Sleep?

Sleep issues have been linked to mental health and performance concerns, as well as an increased risk for cardiovascular and metabolic illness, driving accidents, and permanent fatigue. In fact, it has been shown to cause death according to lab studies on animals. However, even taking certain experiments with prisoners into account, there are no people who have been known to die from a sleep deficit.

Symptoms of chronic lack of sleep are manifested in cases of a prolonged insufficiency of quantity and/or quality of sleep. Even an hour less than the recommended night’s sleep (which is approximately 7–8 hours), when it happens regularly, can have severe consequences on a person’s health and optimal brain activity. The effects of sleep deprivation range from common complaints, such as drowsiness, to more severe symptoms, such as hallucinations, memory problems, and chronic pain

The severity of lost sleep depends on two factors. First, you will suffer more from the symptoms of insomnia as you spend more time awake. For example, staying one hour more to watch your favorite TV show will have less problematic sleep deprivation symptoms than sleeping for only four hours. This can be especially true when it happens every night or when you aren’t sleeping all night. 

Second, the intensity of your symptoms will vary depending on your biological clock. Therefore, the signs of lack of sleep will seem much more pronounced at times when you naturally need to sleep (i.e., the night time).

What Are the Most Common Sleep Debt Symptoms and Causes?

Lack of sleep can lead to decreased concentration, daytime sleepiness, and serious long-term health effects, like obesity. However, the effects brought on by lack of sleep will occur depending on individual sleep needs, but if you get less sleep than you need, it will inevitably lead to significant debt of sleep.

The causes of chronic sleep problems and deprivation can vary. On the one hand, they can be attributed to specific lifestyle patterns: the sleep deprivation may be volitional, which might involve working two or more jobs or being a shift work employee, choosing to stay up, making frequent trips that involve two or more time-zone changes, living an active life, etc. On the other hand, chronic lack of sleep may be part of the clinical picture of a particular sleep disorder, including insomnia, obstructive sleep apnea, narcolepsy, restless legs syndrome, parasomnia, etc.

Chronic sleep deprivation can be caused by other diseases, such as those that are psychiatric, neurological (including neuropathic pain), gastrointestinal, cancer-based, etc. Whatever the reason, not getting enough sleep for a prolonged period is associated with potential health risks and lost physical functionality.

The most common symptoms of insufficient sleep also include the following: fatigue and irritability, difficulty concentrating, difficulty making decisions and planning tasks, short-term memory impairment, blurred vision, trouble with speech, episodes of confusion, hallucinations, feeling sick, and impotence or a reduction in sexual arousal.

Chronic sleep debt is a potentially dangerous phenomenon, especially when episodes of falling asleep occur while traveling or working because they’re associated with a high accident risk. Psychosis may arise in extreme cases. Impairment in cognitive processes—planning, task completion, decision making, maintaining concentration, and more—are the most noticeable, prominent signs.

Moreover, the consequences of consistently getting poor sleep may include obesity, impaired glucose tolerance and diabetes mellitus, cardiovascular complications, depression, anxiety disorders, alcohol abuse, immunity impairment, and a higher risk of developing infections.

How to Prevent Sleep Deprivation

Sleep Debt - Prevent Sleep Deprivation

The importance of sleep and the way that it impacts the onset of physical and mental illness has been studied continuously. To improve a person’s quality and quantity of sleep, it is necessary, first and foremost, to improve their sleep habits. It’s also necessary to identify any underlying illnesses that can cause any of the known symptoms of lack of sleep. In most cases, the treatment and management of any illnesses will help normalize sleep concerns and reduce the risk of any sleep-based complications.

To enjoy a good mood, the body must be rested, meaning you need to have enough sleep. According to multiple studies, a person has to sleep more than 4–5 hours per night. If they don’t, he or she will be sleep deprived and will experience signs of mental exhaustion within a week.

When a person doesn’t get enough sleep, he or she inadvertently begins to eat food in larger quantities. The result is rapid weight gain. The explanation is simple—when one is unable to fall asleep, he or she most often goes to the refrigerator because eating is an easy escape from boredom. 

Furthermore, when you’re tired like this, your body’s production of cortisol increases. This hormone provokes feelings of hunger. According to a 2011 study, people who have less than six hours of sleep during the night have a 30% higher risk of being overweight and obese. Thus, for those experiencing problems with sleep deprivation, treatments should be implemented. If these complications can be reduced, it’s likely that one’s previous state of good health will be restored.

Sometimes a melatonin deficiency—as a consequence of aging or staying up late—additionally contributes to these symptoms. This hormone, which is responsible for sleep, can actually be taken as a sleep aid before bedtime. Furthermore, some products are rich in melatonin, such as honey, milk, and turkey. On the contrary, using coffee to counteract fatigue and drowsiness can have the opposite effects.

How Is Sleep Debt Calculated? 

Everyone can calculate this. First, you have to estimate how many hours spent asleep are sufficient for you to feel rested and alert. Second, you have to count how many hours you actually spend asleep during the night. To be healthy and able to work, specialists recommend a minimum of 7–9 hours of sleep a day.

For example, if you need eight hours of sleep each night but only get five hours on average, you’ve accumulated a sleep debt of 10 hours each week! This is even more frightening when you calculate your lost hours for an entire year. If we use the example mentioned above, then for a year, you lose 520 hours of sleep, or almost 22 days! The higher the debt is, the more the risk of sudden cardiac death increases.

Can You Catch up on Lost Sleep?

The short answer is no. Once sleep is lost, it can’t be repaid. However, although we can’t catch up on hundreds of hours of missed sleep, sleeping enough for a short period can help restore some of the cognitive decline caused by its deprivation.

Interestingly, the body does try to restore itself during certain sleep stages. When a sleep-deprived person rests, the brain spends more time in the deeper phases, which are considered the more restorative stages of sleep, instead of the superficial sleep stages. In this way, catching up on sleep becomes a possibility.

Studies demonstrated that the sleep stages in people who don’t get enough sleep are changed. Generally, alterations in the sleep cycle are resolved immediately if the person starts sleeping more again. Since each sleep stage is crucial for your wellbeing—it’s essential to allow enough time for the brain to move through all the stages of sleep. A skewed sleep cycle in people chronically deprived of sleep doesn’t allow for the needed amount of rest. In line with this, to compensate for the lost sleep, we need to think about reducing and recovering from sleep deprivation.

Is it possible to make up for lost sleep or even erase it? No, but we can make the effort to stop adding hours to our debt and get adequate sleep each night. So when you determine how much sleep per night makes you feel great, adhere to this by creating a schedule that allows enough time for rest. A journal where you track your sleep habits and hours may help you understand your sleep patterns—and possibly add more sleep time.

Do Naps Count as Sleep?

Sleep Debt - Naps

Unfortunately, we can’t sleep more in advance to make up for potential lost sleep in the future. However, some tips can help us avoid the accumulation of lost sleep:

  • Have a regular time for when you fall asleep and wake up.
  • Get to bed earlier to allow enough time to fall asleep naturally without cutting into your total sleep time.
  • When you’re tired, go to sleep instead of using caffeinated drinks to stay awake.
  • Electronics should be avoided within two hours before going to bed. You can find more tips on how to use technology smartly from this useful infographic.
  • Create a dark, quiet, and cool sleep environment.
  • Nap whenever possible.

Taking naps is an excellent way of repaying sleep debt. A midday nap between 11 a.m. and 3 p.m. that lasts around 15–20 minutes can help us restore our alertness until we get more rest at night. However, we have to avoid napping too late because this makes it harder to sleep at night. Once you estimate how much sleep you need each night, keeping firm sleep hygiene habits will help you sleep enough.


How long can you go without sleep? 

The longest continued duration with no sleep was recorded at approximately 264 hours, or 11 consecutive days. However, it’s still unclear how long a human can survive without sleep. Most sleep-deprivation side effects are visible after 3-4 days without sleep, such as having hallucinations.

Is 5 hours of sleep enough?

It’s recommended that people sleep no less than 7–8 hours daily, and children need around 10 hours of sleep depending on their age. Some individuals could function well with less than six hours of sleep a night. However, they will likely be prone to some health issues as a consequence.

What happens after 24 hours of no sleep?

Usually, if accidental, no sleep for 24 hours won’t be too serious, and most people can handle this without any consequences. However, 48 hours without sleeping will lead to a decrease in a person’s cognitive performance due to severe fatigue. At this point, the brain can suffer some brief periods of complete unconsciousness, also known as micro sleeping, and a person could even start hallucinating.


Sleep debt is found in those who regularly don’t get enough sleep. And when this lack of sleep becomes chronic, it leads to serious health consequences. Whatever the cause of the accumulation of lost sleep, it’s expected that the condition will grow more severe over time. For this reason, identifying the underlying causes can help fix the problem. This can be primarily achieved by adhering to a strict sleep hygiene plan that ensures you get the right quality and quantity of nightly rest.

At medical school, it was easy to realize that sleep is crucial while studying during the many sleepless nights I spent. As a new mom, when the lack of sleep became even more evident, this was the real moment when I started appreciating the benefits of a good night’s sleep. Since sleeping is so essential to our health and immune system, I took it upon myself to educate people on different aspects of sleep by sharing the valuable information I have learned.

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