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Why Sleep Is Important

Why Sleep Is Important- 8 Consequences of Sleep Deprivation

Why Sleep Is Important- 8 Consequences of Sleep Deprivation

What Is Sleep?

Sleep is a complex and essential biological process that is required on a daily basis for all humans regardless of age, sex or ethnic origin.

Why Is Sleep Important?

Sleep is a vital process and has many important functions such as memory processing, learning, brain development, and cellular repair. We still do not fully understand why we sleep, what induces sleep, and what induces wakefulness. Even how many hours are needed to achieve ‘restorative sleep’ is still not fully understood.

Sleep also has important roles in controlling the functions of many other body systems. This becomes very evident in states of sleep deprivation.

Do We Need More Sleep?

The average total hours that each person gets per night has decreased to less than seven hours per night over the last three to four decades. This is becoming increasingly common in today’s society due to changes in sleep culture and the adoption of a 24/7 lifestyle, along with longer working hours.

Kripke et al. presented data from a survey that was conducted in the United States in the 1960s describing an average sleep duration of 8 to 8.9 hours per night. A few decades later, this figure had dropped to 7 hours per night. More recent data show a further drop in average levels of night-time sleep in adults to less than 6 hours.

This reduction in sleep quantity leading to sleep deprivation has been associated with a number of physiological changes. These changes include increased ghrelin levels, decreased leptin levels, impaired glucose metabolism, and increased cortisol levels. Experimental studies have also shown an increase in inflammatory and pro-inflammatory markers, which are indicators of body stress, under sleep deprivation.

It has become very clear that reducing the total hours of nocturnal sleep can lead to serious consequences for almost all bodily organs and systems. This includes immunity decreasing, several hormones becoming up-regulated, and systemic inflammation.

8 Consequences of Sleep Deprivation

1. Immune System

There is significant interaction between sleep and the immune system. Sleep helps the body repair, regenerate, recover and adequate “restorative” sleep is needed to maintain good immunity.

Sleep deprivation is associated with increased daytime sleepiness, reduced neuro-cognitive performance and fatigue.

Chronic sleep deprivation has also been linked to increased all-cause morbidity and mortality.

2. Metabolic & Endocrine

Sleep deprivation has an effect on the metabolic and endocrine systems, with chronic cases causing significant hormonal changes.

Mechanisms affected due to this include alterations in glucose metabolism, upregulation of appetite and reduced energy expenditure as factors leading to the development of diabetes mellitus.

There is a strong link between pathological sleep deprivation—for example, due to sleep-disordered breathing (in particular, OSA)—and metabolic syndrome/diabetes mellitus.

Sleep deprivation is also associated with shorter SWS, increased levels of pro-inflammatory cytokines and low grade inflammation.

3. Hypertension

Sleep deprivation and poor sleep quality are associated with higher risks of developing hypertension. While you sleep your blood pressure goes down, the less sleep you get, the longer your blood pressure stays up during a 24 hour period.

It’s also important to note that there might be a gender difference in response to sleep deprivation and the development of hypertension, as seen in some research.

Clinically, sleep-deprived subjects are at higher risk of developing hypertension.


Both feeding and sleeping/waking cycles are under tight hypothalamic control. Abnormal patterns in one axis would affect the other. This interactive relationship could explain why people who sleep less tend to eat more or why people who eat more tend to sleep more.

Glucose is the body’s primary fuel source and it nourishes every cell in the body. Glucose is used to produce energy for cells in the form of Adenosine Triphosphate (ATP). Too much or too little can wreak havoc on your metabolism. Poor glucose regulation is also the precursor to insulin resistance.

Internationally, diabetes mellitus figures are increasing. It is estimated that the prevalence in adults worldwide will be approximately 5.4% by the year 2025.

In the Western New York Health Study, Rafalson et al. followed 1,455 healthy individuals over a 6 year period. Subjects sleeping less than 6 hours per night had significantly higher fasting blood glucose, which is thought to be mediated by insulin resistance.


In this study, Hall et al. evaluated 1,214 adults in a cross-sectional community-based cohort study. Short sleep, which was associated with higher BMIs, higher fasting blood glucose levels, and dyslipidemia, was also a significant risk factor for metabolic syndrome.


Inflammation is associated with increased risk of cardiovascular disorders, arthritis, diabetes mellitus, and mortality. Systemic inflammation with increased inflammatory markers has been associated with sleep deprivation.

A modest amount of sleep loss alters molecular processes that drive cellular immune activation and induce inflammatory cytokines. This creates a greater risk for heart-related conditions.

Sleep deprivation is also linked to increased daytime levels of inflammatory mediators.


When you sleep your brain processes your emotions and your mind needs this time in order to recognize and react the right way.

Sleep deprived-subjects, tend to have more negative emotional reactions and are at a higher risk of developing depression. Your odds of anxiety and panic disorders are also increased.


People who sleep less tend to eat more and have higher instances of cravings. This is because sleep patterns affect the hormones responsible for appetite (ghrelin and leptin). These hormones send signals to and from your brain and stomach that tell you when to eat and when to stop eating.

Sleep deprivation can interfere with your body’s ability to regulate food intake correctly. This results in situations where you may possibly overeat even though these decisions are not in line with your weight loss goals.

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