Tired firefighter
10 Apr 2019

Scientific evidence proving that lack of sleep can contribute to serious work related diseases - including cancer

A lack of sleep can cause early death, cancer, stroke, heart attack, diabetes and more  according to several scientific studies


The effects of sleep deprivation can have serious consequences on a person´s health. A lack of sleep can cause weight gain, high blood pressure, heart disease, and mood swings. Not getting adequate sleep can even increase the risk of diseases such as cancer,  according to an article in Healthy and Natural World.

Most people need between 7 or 8 hours of sleep each night. Having trouble falling asleep, like many firefighters do after a call, or waking up frequently during the night like firefighters often do when dealing with multiple calls in the same overnight shift, is now proven to have serious bad health impacts. 

The studies were not done specifically on firefighters, and given that firefighters are sometimes slightly differently "wired" than the general population, one could possibly argue the studies referenced may not be applicable in every individual case for a firefighter - however, when it comes to work related illnesses, it would likely not be wise to disregard these findings either. And from a workers´ safety standpoint, sleep deprivation can likely no longer be ignored when negotiating firefighters´ working conditions, salaries and health benefits.

The studies, although focusing on various types of illnesses, and not necessarily being conclusive for every single one of the illnesses mentioned, are still very conclusive: Prolonged lack of sleep, like what firefighters are experiencing when regularly scheduled on overnight calls, is seriously bad for the body´s long term health in so many ways. 


Tired firefighterWhat is Sleep Deprivation?

Sleep deprivation happens when you don’t get enough sleep for your body to function properly.

The journal PLoS One says that you need between 7 and 8 hours of good quality sleep every night. Regularly sleeping less than 6 hours a night can put a person at risk for developing  conditions such as diabetes, heart disease or stroke. 

According to the National Heart, Lung, and Blood Institute, getting enough sleep is essential for good health. Sleep is a basic need of the body, and the effects of sleep deprivation can be as serious as not eating or breathing. Not sleeping enough affects both physical and mental health.

The effects of poor sleep can also build up over time. Although napping can help to reduce some of the effects of little sleep, it is not a substitute for getting a good night’s sleep regularly.

There are also different stages to sleep – rapid eye movement (REM) sleep and non-rapid eye movement sleep. REM sleep is generally the time when your brain is active during sleep and you dream. Non-REM sleep is a deeper sleep when the body and mind repair themselves. 

One study found that sleep deprivation during different sleep stages affects the  mind in different ways. For example, loss of sleep in the REM stage can affect learning ability. 


Lack of Sleep Can Cause Weight Gain

Putting on extra weight is one of the physical effects of sleep deprivation.

One of the reasons why chronic sleep deficiency causes overweight is that it affects the body´s hormones. Studies report that the hunger hormone ghrelin increases when the body is  deprived of sleep. At the same time, lack of sleep inhibits leptin – the hormone that makes a person feel full. This hormonal imbalance can lead to overeating and obesity. (6)

One cohort study involving over 1,000 adults found that short sleep is associated with an increased risk of weight gain. Sleeping 5 hours or less increased ghrelin and decreased leptin hormones which are linked to increased incidences of obesity. 

Sleep deprivation can affect weight because it also affects glucose tolerance and insulin sensitivity. This lack of sleep can cause fat accumulation and increase the risk of obesity.


Long Term Sleep Deprivation May Lead to Cancer

Insufficient sleep can be one of the factors that can increase riska of developing cancer.

The Journal of Cancer reports that chronic sleep deprivation is associated with incidences of cancer. For example, insomnia or sleep apnea can increase a person’s risk of breast cancer, oral cancer, or prostate cancer. 

Some studies, however, have not found a definite link between the long-term effects of sleep deprivation and cancer. Interestingly, regularly sleeping longer than 8 hours a night could increase the risk of colorectal cancer. 


Lack of sleep may increase risk of early death

Although there is no evidence that you can die directly from a lack of sleep, sleep deprivation can lead to early death.

A report published in 2010 found that people who averaged 7 hours of sleep every night have the lowest mortality risk. Sleeping less than 7 hours or sleeping longer is associated with an increased risk of dying early. Researchers found that the effects of not getting enough sleep lead to serious health conditions that can shorten your life. 

Poor sleep causes cardiovascular disease, obesity, diabetes, and stress. One or more of these conditions combined can decrease your life expectancy. 


Too little sleep causes chronic inflammation

Because a loss of sleep doesn’t allow your body time to repair itself and recharge itself, sleep exhaustion can cause chronic inflammation.

Inflammation in the short term is necessary to help your body fight disease. However, long-term inflammation can put you at risk of developing chronic diseases such as cancer, diabetes, and heart disease.

For example, the book StatPearls reports that chronic inflammation is a side effect of chronic sleep disorders. Lack of sleep and stress (that often causes sleepless nights) cause the body to release inflammatory enzymes. One of the ways to combat chronic inflammation is to sleep between 7 and 8 hours every night. 

Research into the long-term effects of sleep deprivation has found that it has the potential to cause mild to moderate organ damage. Sleeping well every night can help to improve your gastrointestinal and cardiovascular health. 


Lack of sleep makes the body vulnerable to infection

One of the risks of sleep deprivation is that the body is more prone to infection. The journal Sleep explains why not getting enough sleep makes a person sick. When experiencing chronic sleep deprivation, it alters cellular immune responses in the body and increases biomarkers of inflammation. 

The results of a 2017 study showed that contracting infectious diseases is one of the risks of sleep deprivation. The study found that persistent lack of sleep increased inflammatory cytokines that negatively impacted on the immune system. Adequate sleep has a powerful effect on a person’s immunity. 


Not getting enough sleep negatively affects brain function

Lack of sleep directly affects mental abilities and it has negative effects on the brain.

Most of us know that not getting enough sleep leaves us feeling tired, frustrated, forgetful, and having difficulty concentrating the next day. However, the long-term effects of little sleep can be even more worrying.

A lack of sleep over a long period of time can build up a "sleep debt" that impairs cognitive ability. Research has found that sleep deprivation can result in memory loss and lower attention span. A chronic lack of sleep can also make it harder to solve problems and cope with complex tasks. 

Research on animal subjects found that sleeping for 5 hours or less will significantly affect brain function. Even brief periods of sleep deprivation can negatively impact on memory function. When a person “catches up on lost sleep,” brain function should be restored. 


Chronic sleep deprivation can lead to depression and mood changes

One of the psychological effects of sleep deprivation is depression.

Researchers have found that the dangers of a long-term lack of sleep are depression and mood disorders. Restricted sleep affects hormone levels in the brain that can lead to depressive thoughts and behavioral changes. Serotonin is released during REM sleep, and a lack of serotonin is often connected to depression. 

The negative effects on the brain of not sleeping are also highlighted when a person is deprived of sleep. The journal Frontiers in Psychiatry in 2018 reported that sleep deprivation can cause hallucinations and episodes of psychosis. 

Interestingly, some therapists use sleep deprivation techniques for treating depression. This can be used as a short-term remedy for depression under the guidance of a trained medical professional. 

This may explain why some people feel better with less sleep. However, as this article points out, there are many dangers associated with a chronic lack of sleep.


Loss of sleep can lead to type 2 diabetes

The consequences of sleep deprivation can cause a number of metabolic conditions in the body that can cause diabetes. Studies have shown that little sleep affects nighttime glucose regulation. Also, sleep disorders can cause obesity which increases the diabetes risk.

The study concluded that chronic sleep loss predisposes a person to diabetes. 

A review of studies on the effects of sleep on diabetes over a 10-year period found that sleeping less than 5 hours a night or longer than 9 hours a night increases the risk of becoming a diabetic. 


Sleep deficiency may cause heart disease

A 2016 study found that people who have short sleep or disrupted sleep patterns suffer more from heart disease. Also, building up a large sleep debt can increase mortality rates from cardiovascular problems. 

One study found that regularly sleeping 4 hours or less can increase a man’s risk of dying from heart disease by 2.8 times when compared to men who sleep for the recommended 7 hours a night. 

Similarly, women who slept less than 6 hours a night were more at risk from heart disease mortality than women who slept for 7 to 8 hours every night. 


Poor sleep quality may increase blood pressure

One study looked at the effects on blood pressure of not sleeping for 24 hours. Scientists noted that heart rate increased during nighttime hours when a person should be sleeping. The next morning, both blood pressure and heart rate were elevated. The study confirmed that the side effects of not enough sleep can be high blood pressure and increased risk of cardiovascular disease. 

Other studies confirm that the effects of sleep deprivation can lead to hypertension and cardiovascular events, especially in elderly persons. 


Severe sleep deprivation increases the risk of stroke

The consequences of not sleeping enough can be very serious if you are already at risk of a stroke.

Of course, high blood pressure, diabetes, obesity, and an irregular heartbeat are serious risk factors for stroke. However, the journal Frontiers in Neurology reported that getting enough sleep could be a way to prevent stroke if you have these risk factors. The researchers reported that a lack of sleep has a great impact on the chances of having a stroke. 


Not getting enough sleep can affect hormone levels

Disrupted sleep patterns, going to bed late and waking up early, or poor sleep quality can have impact on hormone production.

According to the International Journal of Endocrinology, your hormonal balance depends greatly on sleep quality. Your sleep (or lack of it) affects hormones such as thyroid hormones, melatonin, cortisol, growth hormones, and hunger hormones. 

Sleep deprivation increases your risk of hormone-related conditions such as obesity, diabetes, and thyroid issues


Lack of sleep kills sex drive

One study found that men who suffer from sleep disorders and don’t get quality sleep have a lower sex drive. Poor sleep quality and loss of sleep affect testosterone levels and, therefore, affects sexual desire. 

A severe sleep deficiency can cause obesity which can also impact on testosterone hormone levels. This is another reason why not getting enough sleep can affect your sex life. 


Sleep exhaustion can cause you to make fatal mistakes

Although it is virtually impossible to die from sleep deprivation, sleep exhaustion can cause mistakes that can have fatal consequences.

For example, driving while drowsy due to a loss of sleep can cause serious car accidents. In fact, some studies report that about 12% of all vehicle accidents are due to sleepiness. Scientists say that even a modest lack of sleep can impair judgment and reaction time. 

A 2015 report warns that medical professionals who suffer from sleep deprivation are more prone to making mistakes and put patient safety at risk. 

Interestingly, one study found that rats who were totally deprived of sleep eventually died of a lack of sleep after 11-32 days.