Sleeping is a natural necessity for all of us, but just how important is it? Studies taken out by researchers in the hope of understanding sleeping behaviour and importance have found a number of links between body fat and sleep. The correlations show that those who sleep for a shorter length of time each night typically have a higher body fat level. Even when taking into account other possible factors, and removing certain other factors from the equations, there still appears to be a strong correlation between a lack of sleep, and higher body fat levels.
Some fat loss diets actually recommend that you can lose weight by reducing the amount of sleep you have, sometimes by up to three hours per night. However, it’s believed by most researchers that this would have negative nutritional partitioning effect, and would mean that any weight loss would be achieved by loss of lean mass, rather than by the loss of fat mass. In the short term, a lack of sleep can actually lead to an increased appetite, which can be compounded if paired with a controlled caloric intake. In a study of otherwise healthy women, this has been reported as having approximately a 20% increase in voluntary energy intake, and as much as a 0.4kg increase in body weight over four days.
Numerous studies show that sleep deprivation, especially over a long period of time, can lead to higher fat mass gains, and that even short term sleep loss can hinder fat loss attempts, as the percentage of loss being via fat loss is lowered by the lack of sleep.
A lack of sleep can also result in a neural sleep wave pattern that is similar to what is sometimes observed in individuals with depression. The cognitive well-being of individuals can often be linked with the amount, and quality, of sleep the individuals receive. A reduction in the amount of sleep received can often lead to a decrease in cognitive performances such as problem solving. Impaired sleep can be linked to impaired cognitive functions.
Links can also be drawn between irregular sleep patterns and various conditions and syndromes. Shortened sleep patterns, as well as some cases of excessive sleeping habits, have been connected with an increase in the chances of developing diabetes. Those who receive 7-8 hours of sleep each night seem to be at the lowest risk of developing diabetes. There seems to be a similar level for the increase in developing the condition with those who get 5-6 hours of sleep, and those who get 8-9 hours of sleep. Sleep time can be a contributing factor to the level of testosterone in older men, and during the process of aging, testosterone levels can be further linked with sleep patterns.
In a study which carried out research on otherwise healthy women, the researchers discovered that those women who were sleep deprived had increased thyroid hormones T3 (19%) and T4 (10%). However, some other trials have failed to find this correlation between lower levels of sleep and increase thyroid hormones. One study found that the increase hormones could be found in acute sleep deprivation, but not in individuals suffering from chronic sleep deprivation.
Another impact a lack of sleep can have on an individual is the level of growth hormones which occur. For young persons, the largest spike of growth hormones they receive is mediated by sleep, and accounts for up to half of the total daily exposure they receive. Studies have found that sleep deprived individuals have a decreased level of growth hormones, which can be directly linked to the quality and amount of their sleep.