The nature of today’s fast paced, anxiety-filled, and busy society of overloaded schedules, has made a lot of people to resort to shortchanging themselves on the number of hours they spend sleeping per night. This is however a disturbing development as several new scientific studies have found that lack of sleep may actually be hindering a lot of people from losing weight.
It has been demonstrated that high quality, healthy and consistent sleep cycles significantly affects an individual’s metabolic health through the balancing of hormones responsible for appetite control, food cravings, and overeating. Inadequate night sleep does not only make an individual tired but research studies now say that it can also inhibit weight loss.
The effect of sleep on body weight is somehow directly or indirectly linked to its effect on certain hormonal changes that promote weight gain. Of particular interest would be how sleep affects the secretion of leptin, ghrelin, and insulin – all hormones that play significant functions in appetite regulation. There is also the need to consider the role of fatigue and stress – both side effects of lack of sleep – and their effect on the stress hormone, cortisol.
The effects of lack of adequate sleep on some of these hormones were brought to the fore by a study carried out by researchers at the University of Bristol. In their research, the scientists observed that people who had a five-hour per night sleep had a 15% reduction in the production of leptin and also an equally interesting 15% increase in the production of ghrelin when compared to people who had an eight-hour per night sleep.
The study also found that lack of sufficient sleep disturbs glucose metabolism and insulin sensitivity. Insulin resistance or insensitivity generally leads to the accumulation of excess amounts of glucose in the bloodstream and the tendency of the body storing same as fat. The study concluded that sleep deprivation may trigger appetite and cravings for sugar-rich, calorie-dense foods.
To start with, leptin is derived from the Greek word meaning “thin” and is a protein hormone secreted by fat cells. Leptin functions as a natural biochemical appetite suppressant that makes you feel full and satiated by sending signals to the hypothalamus notifying it that the body has eaten enough calories and therefore to stop eating.
Low levels of leptin occasioned by loss of sleep can make it difficult for an individual to cope with the constant feelings of hunger and increased appetite. Furthermore, lack of adequate sleep affects leptin through the reduction of the sleep hormone – melatonin. Melatonin is known to assist in the healing and restoration of the sensitivity of leptin receptors.
Leptin resistance or insensitivity is the “de-sensitization” of the brain to the effect of leptin occasioned by either engaging in overeating or the inability of the chemical signals sent by the secreted leptin hormones to cross the blood-brain barrier. Not receiving the leptin signals or incorrectly interpreting them causes the brain not to properly receive the “I’m full” signal and thus the tendency of the individual engaging in overeating.
On the other hand, the lack of adequate sleep increases the secretion of the hunger-promoting hormone known as ghrelin. Ghrelin is secreted by the cells in the lining of the stomach and activates the appetite. Elevated ghrelin levels essentially promotes overeating since they signal the need for the body to eat in order to stock up its energy reserve despite the fact that the body might not actually be in need of the extra energy.
Besides the above hormones, the neurotransmitter known as serotonin has also been shown to be affected by lack of adequate sleep. Serotonin generally helps to maintain a relaxed feeling or mood, promote good sleep patterns, as well as regulating the feeling of satiety and fullness.
Low levels of serotonin can lead to increased irritability and mood swings and also the craving for carbohydrate- and fat-rich foods such as cookies, roasted nuts, chocolates, cakes and potatoes chips. One notable feature of depression is actually the reduced amount of serotonin in the brain. Irritability, mood swings, and depression are all conditions that generally predispose a person to compulsive eating behaviors.
Furthermore, sleep deprivation also leads to increased secretion of the stress hormone called cortisol. Several studies have found that cells around the stomach love to attract cortisol and which makes a lot of people to add weight around the abdominal and hip areas.
Despite the fact that disruption in sleep patterns and actual sleep deprivation may not be the main reasons behind the growing global obesity epidemic, it nonetheless poses a great threat. There must be a hormonal balance for weight loss to occur and be effective, however lack of adequate sleep only tend to further distort this balance.
Therefore it is important to ensure to get an adequate night sleep of about eight hours per night as an adult in order to have an improved overall healthy life and to also get the best weight loss results.
