Function of Sleep

Sleep is essential to protect the mental and physical health of an individual, in addition to improving the quality of life. However, the function of sleep has not always been clear and, until recently, the main function was believed to be the avoidance of sleep deprivation.

During sleep, there are a number of important processes that occur to support the healthy function of the brain and overall physical health, which are particularly important for children and adolescents.

Brain Function

Sleep plays an important role in the function of the brain, by forming new pathways and processing information. Research has shown that adequate sleep helps to improve memory and learning, increase attention and creativity, and aid in making decisions.

When an individual has had insufficient sleep, physical changes occur in the brain, which alter the activity and function of the brain. Individuals that have not had adequate sleep may have difficulty making decisions, problem solving, controlling emotions and coping with change. Lack of sleep is also associated with depression, suicide and risk-taking behavior.

Memory

Sleep plays an essential role in the consolidation of memory and the selection of important information and stimuli received throughout the day. Naturally, individuals don’t remember every detail but tend to prioritise certain information, due to an emotional or other connection.

It is believed that sleeping and dreaming help in the process of sorting through experiences and memories to isolate and store the gist or specific detail of the memory. According to Stickgold, “When we dream, we get the pieces. When we wake, we can know the whole.”

Additionally, sleeping is thought to help clear out toxins that accumulate in the brain throughout normal daily activities. Beta-amyloid is a protein associated with Alzheimer’s disease is an example of one such toxin. During sleep, channels in the brain expand to allow the flow of cerebrospinal fluid to clear the debris, known as the glymphatic system, due to the similarity to the lymphatic system.

Physical Health

Sleep is also essential for maintenance of physical health of the body, particularly in the healing and repair of cells, such as those in the cardiovascular system.

It also helps to maintain the balance of hormones in the body, such as ghrelin and leptin, which regulate feelings of hunger and fullness and is likely to explain the link between inadequate sleep and increased risk of obesity. Other hormones such as insulin, which is responsible for the regulation of glucose in the blood, also change and can result in an increase in blood sugar level. For this reason, chronic sleep deficiency is also linked to a higher risk of cardiovascular disease, stroke, diabetes and kidney disease.

The processes of growth and development are also intricately involved with sleep. Deep sleep triggers the release of growth-promoting hormones, which boost muscle mass and repair cells and tissues in the body.

The immune system also relies on sufficient quantity and quality of sleep and deficiency in sleep is linked to difficulty fighting infection and increased risk of sickness.

Finally, sleep is a strong determinant of productivity during the day at work or in studies. People who lack adequate sleep, often take longer to finish tasks, are more likely to make mistakes and have a slower reaction time.

References

• http://www.newyorker.com/science/maria-konnikova/why-we-sleep
• http://onlinelibrary.wiley.com/doi/10.1111/j.1460-9568.2009.06746.x/full
• http://www.nhlbi.nih.gov/health/health-topics/topics/sdd/why
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4180265/