What is sleep?

Sleep is for the life of vital importance. It supports numerous physiological and psychological functions such as tissue regeneration, growth, strengthening of memory and learning. While adults have different sleep needs, experts believe that sleep duration of continuously less than 7 hours per night could have negative effects on the brain and the body are.

Sleep and the metabolism
In examining the relationship between sleep and metabolism, it is often difficult to distinguish whether certain metabolic factors affect sleep or whether the quality and length of sleep affect your metabolism. For example, more deep sleep is observed in physically active people and in people with hyperthyroidism, both of which are associated with a faster metabolism. In contrast, people make do with hypothyroidism – and thus a slower metabolism – with fewer hours of deep sleep.

Reversing the correlations can be observed that sleep deprivation is associated with numerous adverse changes in metabolic activity. For example, the levels of cortisol in the blood increases (this hormone is involved in stress reactions), the immune response is impaired, the body’s ability in dealing with glucose decreases and appetite control suffers. Similar changes are observed in those whose sleep structure is z. B. disturbed by young children or illness. In effect, the normal body function is disturbed due to lack of sleep, which has consequences on the metabolism.

Does lack of sleep influence health?
Laboratory tests and epidemiological studies suggest that sleep loss may play a role in the increased prevalence of diabetes and obesity. When correlation between the lack of sleep, weight gain and the risk of diabetes may play a role change of glucose metabolism, increased appetite and decreased energy consumption spielen.1

Sleep and glucose metabolism
Shorter sleep stages are associated with impaired glucose tolerance with increased cortisol concentration in the blood. The term glucose tolerance describes how the body controls the distribution of glucose between blood and tissue. High concentrations of glucose and the hormone insulin in the bloodstream in the fasted state indicate that the body does not adequately deal with the glucose. It has been proven that low glucose tolerance is a risk factor for diabetes type. 2 According to the research can cause a 40% drop in the glucose tolerance of long-term sleep loss (<6.5 hours per night).

Increased appetite
There was a correlation between habitual short sleep time and increased body mass index (BMI) reported in large populations. Short sleep was associated with changes in hormone levels that control hunger: the levels of lepton (appetite reducing) were low, while that of ghrelin (appetizing) were high. These effects were observed when the sleep time under 8 hours fiel.1,3 This suggests that sleep deprivation is a risk factor for obesity. In a controlled study in healthy male volunteers was found that sleep duration of about 4 hours with a significantly higher demand for high-calorie foods with high carbohydrate content (sweets, salty and high-starch diet) was associated. It was also about reported.2 stronger feeling of hunger
A shorter sleep time, more time for eating and drinking are available, and there are some research findings that suggest that this is a factor that contributes to the development of obesity in combination with short sleep phases.

Reduced energy consumption

To mention the other side of the energy balance – it is less likely that people are physically active with sleep deprivation, resulting in reduced energy consumption.
In summary, the increase in appetite and desire for food and the reduction of physical activity represent a quick-witted argument for the role of sleep in the handling of body weight.

The vicious circle of disordered sleep and obesity

The disorder, sleep apnea, affects about 24% of men and 9% of women. It is characterized by pauses in breathing during sleep, have a disturbed sleep and daytime fatigue result. There is a strong link between this disease and obesity. Studies have shown that people with sleep apnea experience abnormal sleeping patterns that could exacerbate the problems associated with sleep deprivation metabolic disorders (eg. As increased hunger). It might accordingly the induced by obesity sleep apnea syndrome in turn have an influence on appetite and energy consumption, and in a way which in turn promotes obesity. To fully understand the relationships, further research is needed.


The lack of high quality sleep appears to impact on physiological mechanisms of energy balance, namely appetite, hunger and energy expenditure. Furthermore, sleep deprivation has a negative effect on the ability of the body to handle glucose and may increase the risk of diabetes mellitus type. 2 It is not yet clear to what extent changes in sleep patterns could be used to create a favorable environment for the handling of body weight and for reducing risk of related diseases.