All of us have some notion that our sleep and our ability to stay active during the day are somehow related and all of us have experienced fatigue and bad mood, which are frequently the result of insufficient sleep. Many people don’t understand that lack of sleep affects our health condition significantly. Additional studies indicate that those who sleep more than 9 hours are also in the group of risk.
Duration of night sleep and chronic diseases
There are three main research directions that help us to understand the relation between the sleep behavior and the risk of the development of some serious diseases.
The first type (sleep deprivation) is a study during which healthy people voluntarily refuse to sleep and when short-term physiological changes in their organisms are studied, that can cause higher blood pressure, changes in blood sugar level as well as various inflammations.
The second type of research (one-time epidemiological studies) is an analysis based on the questionnaires where people tell the length of their sleep and their specific illnesses. However, such studies could not fully explain whether poor sleeping is a consequence of such illness or their reason.
The third and most credible type of research is a longtime monitoring the state of a healthy person his/her sleeping behavior and symptoms of any diseases (repeated epidemiological studies). We still don’t know whether it is possible to improve the conditions of a person who already has a disease, however, the results of longitudinal epidemiological studies indicate that this method can have positive results.
A lot of studies reveal that weight gain is connected with wrong sleeping behavior. For example, people who usually sleep less than 6 hours per night, have a higher body mass index than those who sleep 8 hours. After overeating and the lack of physical activity, the lack of sleep is the next most important factor that may cause obesity.
During sleep, our body produces hormones that are responsible for appetite, metabolism and glucose uptake. When we reduce sleeping hours, we distort the balance of hormones production. For example, if you sleep not enough, cortisol level may increase, also known a stress hormone. pPoor sleep can also be the reason of high insulin secretion after meals. This hormone is responsible for glucose uptake and when its level is high it can lead to obesity and diabetes.
Also, the lack of sleep reduces leptin level, a hormone that informs the brain about the satiation and increased levels of ghrelin, which stimulates appetite. These processes lead to the fact that shortly after eating a person wants to eat again, which recharges the body only for a short time. Also, the lack of sleep causes such conditions when a person has no strength to burn extra calories with exercises.
Studies suggest that those people who sleep more when infected, deal with it better than those who sleep less. Animal studies reveal that those individuals who sleep better, have better chances to survive when infected.
Scientists have found that lack of sleep may lead to type 2 diabetes, affecting glucose uptake, a carbohydrate with a high energy level. Poor sleep studies revealed that the group of healthy people whose sleep was reduced from 8 hours to 4 had a lower glucose uptake level than those who were asked to sleep 12 hours. A lot of studies indicate that people who sleep less than 5 hours per night are having the risk of getting diabetes. The researchers also found out a connection between sleep apnea (a disorder when problems with breathing during the sleep lead to frequent awakenings) and the development of changes in glucose level similar to those which are caused by diabetes.
Heart diseases and hypertension
Scientists have found that if a person with hypertension has one night of short, poor sleep it can increase the level of blood pressure for the whole day. This effect can explain the relation between short sleep and cardiovascular diseases. For example, one of the studies shows that sleeping less than 6 hours or, on the contrary, more than 9 hours can increase the risk of heart attack among women. There are also plenty of facts proving the connection between sleep apnea and cardiovascular diseases. Waking up at night due to the closure of the airway and inability to breathe, people experience severe bouts of high blood pressure that over time can lead to hypertension. Fortunately, when sleep apnea is cured, blood pressure can restore to normal.
Considering that even one sleepless night can make people grumpy and fractious, it could be assumed that chronic sleep deprivation can lead to long-term disorders. The chronic sleeping problems may lead to depression, anxiety as well as mental disorders. During one of the studies, the people who slept four hours and a half per day reported they felt melancholy, aggression, and emotional tension. During the other study, the people under the test who slept four hours per day noted they have become less optimistic and communicative. All these symptoms disappear when people return to their normal sleep schedule.
It is natural for people to sleep a lot when they are sick. Chemicals, produced by the immune system and helping to fight infection, lead to fatigue. The studies reveal that those people who sleep more when infected, deal with it better than those who sleep less. Animal studies tell us that those individuals who sleep better, have more chances to survive when infected.
The studies revealed that alcohol drinking is quite common among the people who have sleeping disorders, and there are several reasons for that. First, alcohol has a mild sedative effect and people suffering from insomnia often use it as a sleep aid. Secondly, the sedative effect of alcohol is only temporal. Alcohol is metabolized by the body within few hours and then begins to stimulate the areas of the brain, which cause excitement and in many cases problems with sleep later during the night.
Considering plenty of potentially unfavorable health consequences caused by insufficient sleep, it isn’t surprising that poor sleep leads to shorter life expectancy. The results revealed by three significant one-stage profound epidemiological studies show that if you sleep five or fewer hours every night it will increase mortality risk by about 15%.