Sleep Deprivation: The Risks And Dangers Of Insufficient Sleep

Sleep is a basic human need, as important as eating, drinking, and breathing. However, sleep deprivation is a common issue, with around 30% of American adults sleeping less than the recommended seven to nine hours per night. Sleep deficiency can have a range of negative impacts on both mental and physical health, as well as affecting productivity and safety.

Increased risk of cardiovascular disease

Sleep deprivation can lead to an increased risk of cardiovascular disease. Research has shown that people who don't get enough sleep have a higher risk of hypertensive heart disease, which is the result of long-term unmanaged high blood pressure. Hypertension can cause geometric changes in myocardial tissues and increase wall stress on the heart. This can lead to concentric remodelling, concentric hypertrophy, and eccentric hypertrophy of the left ventricle. Sleep deprivation is also associated with a proinflammatory state, which can contribute to vascular endothelial dysfunction and the pathogenesis of metabolic and cardiovascular diseases.

In addition, sleep deprivation can cause a disturbance in the normal circadian pattern of blood pressure. Typically, blood pressure fluctuates over a 24-hour period, dipping at night and peaking in the afternoon. However, in people who are sleep-deprived, there is a lack of nocturnal dip in blood pressure, and a persistently activated sympathetic nervous system, which results in elevated blood pressure. This disruption in the normal sleep-wake cycle can increase the risk of developing hypertension or worsen pre-existing high blood pressure.

Sleep deprivation has also been linked to atherosclerosis, which is the build-up of plaque in the arteries. Poor sleep triggers chronic inflammation, which contributes to plaque formation and the hardening of the arteries. Sleep deprivation is also associated with increased levels of vasoconstrictors like endothelin, which can cause elevated blood pressure. Furthermore, sleep-deprived patients often have increased levels of counter-regulatory hormones, which cause vasoconstriction and can lead to negative cardiovascular outcomes.

People who don't get enough sleep are also more likely to have higher levels of cortisol, which can cause fluid retention and worsen extracellular fluid volume, leading to uncontrolled hypertension. Chronically high cortisol levels can increase afterload, leading to remodelling of the left ventricular structure and the development of hypertensive heart disease.

Overall, sleep deprivation is a significant risk factor for cardiovascular disease, and it is important for people to make getting enough sleep a priority to maintain heart health.

Poor balance and coordination

Sleep is a complex physiological function that is essential for cognitive and motor performance. Sleep disturbances can affect learning, memory, attention, and cognition in multiple ways.

Sleep deprivation, whether acute or chronic, negatively affects several functions, including motor control. Balance control is essential in several daily life activities, and balance problems are related to falls.

Postural Control and Sleep Deprivation

Postural control describes the task of controlling the body position in space for stability, guaranteeing balance and orientation of the body segments for perception and action. Postural control requires the integration of different sensory systems, including visual, vestibular, and proprioceptive sensory systems, to produce adequate muscle tone and motor actions to maintain balance.

Several studies have shown a decrease in performance in controlling balance after one night of sleep deprivation. Recent studies have also pointed out that balance control can be impaired under more subtle sleep restriction conditions, such as chronic sleep deprivation or social jet lag.

Effects of Sleep Deprivation on Balance Control

The reviewed literature shows strong evidence that acute sleep deprivation impairs postural control. Chronic sleep deprivation and low sleep quality have similar effects, although there are fewer studies addressing this issue.

The sleep deprivation showed a stronger negative effect on postural control when removing visual information (eyes closed) than when reducing proprioceptive feedback (soft surface). There is scarce literature about the effects of chronotype, circadian patterns, and chronic sleep deprivation on balance control. However, they consistently indicate a relationship between them.

The evidence suggests that the sleep conditions of a subject should be considered for several days before balance control tests. Therefore, it is recommended to monitor sleep and circadian rhythm for a minimum of nine days before balance control experiments to observe the routine changes caused by social obligations throughout the week.

Sleep Deprivation and Sensory Perturbations

Balance control relies on visual, proprioceptive, and vestibular information. While vision is the most important, the removal of any of these senses compromises balance. Therefore, sleep deprivation affects the metabolism of the thalamus, cerebellum, and basal ganglia, which are responsible for sensory integration and motor coordination, ultimately affecting balance.

This explains the more marked balance performance decrease under sleep deprivation when the eyes are closed. One of these studies reported that the closed-eyes condition was more challenging for the elderly than for young adults. The authors claim that sleep disorders, which are common in senescence, can increase the risk of falling, and suggest that improving sleep quality would help prevent falls.

Circadian Rhythm and Chronotype

The study of sleep is connected to the circadian oscillation. However, the assessment of circadian rhythm and chronotype is considered in only a few papers. Some argue that the circadian oscillation was respected by performing tests at similar times, while others claim that the circadian timing system has individual adjustments that vary for each subject, following the chronotype characteristics.

As the circadian rhythm influences balance, it is important to control this parameter to compare balance performance. The worst performance in posture control was described to occur during the biological nighttime.

Higher stress levels

Sleep deprivation may raise cortisol levels, the stress hormone, which can contribute to weight gain, heart disease, anxiety, signs of ageing and more.

The Stress-Sleep Cycle

Stress and sleep are closely linked. Research has shown that 43% of people aged 13–64 have reported lying awake at night due to stress at least once in the past month. Many people report that their stress increases when the length and quality of their sleep decreases.

Stress and Sleep in Adults

Adults who sleep fewer than eight hours a night report higher stress levels than those who sleep at least eight hours a night. Adults with higher reported stress levels are more likely to feel more stressed if they do not get enough sleep.

Stress and Sleep in Teens

Teens who sleep fewer than eight hours per school night report higher stress levels in the past month than teens who sleep at least eight hours per school night. They are also more likely to report experiencing symptoms of stress, such as feeling irritable or angry, nervous or anxious, depressed or sad, and overwhelmed.

Stress and Sleep in Younger Generations

Younger Americans (Millennials and Gen Xers) report getting fewer hours of sleep per night on average, and are more likely than other adults to say they do not get good-quality sleep and have more trouble achieving their sleep goals.

Changes in your appearance

Sleep is not just a luxury but a necessity. When you don't get enough sleep, it can show on your face. Sleep deprivation can cause changes in your appearance in the following ways:

Firstly, it can lead to dark circles under your eyes, making you look tired and exhausted. Secondly, sleep deprivation is linked to increased levels of cortisol, a stress hormone that can break down collagen, the protein responsible for keeping your skin smooth. This means a lack of sleep can result in more wrinkles and fine lines, as well as uneven skin tone and looseness.

In a study, participants between the ages of 30 and 50 who slept poorly were found to have more wrinkles, fine lines, and skin issues. They were also less satisfied with their appearance than those who got adequate rest.

Additionally, sleep plays a vital role in regulating the hormones that control hunger and fullness, namely leptin and ghrelin. Sleep deprivation disrupts these hormone levels, leading to increased feelings of hunger and potentially contributing to weight gain and obesity.

Finally, sleep is crucial for the healing and repair of blood vessels and the heart. Sleep deprivation can negatively impact these processes, affecting your physical appearance over time.

Greater chance of car accidents

Sleep deprivation can have a significant impact on your driving ability, increasing the likelihood of being involved in a car accident. Here are some reasons why a lack of sleep can lead to a higher risk of road traffic incidents:

Impaired Judgement and Performance

Sleep-deprived individuals may experience impaired judgement and performance similar to those under the influence of alcohol. Their reaction times, awareness of hazards, and ability to sustain attention all worsen as they become more drowsy. Driving after 20 hours without sleep is comparable to driving with a blood alcohol concentration of 0.08%, the legal limit in most U.S. states. This impairment can lead to slower reaction times, reduced coordination, and poor decision-making, increasing the risk of accidents.

Micro-sleep

Micro-sleep is a common occurrence among drowsy drivers, characterised by short, involuntary periods of inattention. During micro-sleep, a driver may nod off for just a few seconds, but this brief lapse in attention can have dangerous consequences. At highway speeds, a vehicle can travel the length of a football field in just 4 to 5 seconds, providing ample opportunity for a crash to occur.

Higher Risk-Taking

Sleep-deprived individuals may also be more prone to risk-taking behaviours, such as speeding or ignoring traffic signals. This can increase the likelihood of accidents, particularly on rural roads or highways where there may be fewer safety measures in place. Additionally, driving while exhausted can impair one's ability to make safe choices, such as deciding to pull over and rest instead of continuing to drive.

Increased Crash Risk Statistics

According to the National Sleep Foundation, an estimated 6,400 people die annually in crashes involving drowsy driving. The National Highway Traffic Safety Administration (NHTSA) reported that in 2021, 684 people died in drowsy-driving crashes reported by police. However, it is challenging to determine the exact number of crashes caused by drowsy driving, as fatigue is not always recognised or reported. The NHTSA estimates that in 2017, 91,000 police-reported crashes involved drowsy drivers, resulting in approximately 50,000 injuries and 800 deaths.

Vulnerable Groups

Teens and young adults are particularly vulnerable to drowsy driving, as they often do not get enough sleep due to biological changes and lifestyle factors. Shift workers, commercial drivers, and business travellers are also at higher risk due to their irregular work hours and sleep patterns.

In conclusion, sleep deprivation significantly increases the risk of car accidents by impairing judgement, performance, and coordination. Driving while exhausted can have deadly consequences, and it is essential for individuals to prioritise adequate sleep to ensure their safety and the safety of others on the road.

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