The fact that the right amount of time and good quality rest are important to staying well is self-evident. We notice it right away if, while traveling, we change time zones, or even simply if, perhaps on New Year’s Eve we stay up all night. A lack of mental clarity and concentration, irritability, decreased ability to learn and retain information all await us. The consequences of sporadic sleep deprivation are temporary, and usually a good night’s sleep or small steps to resynchronize our circadian rhythm can be enough to get us back in shape. However, when we are faced with sleep disorders that continue over a long period of time, the health consequences can be far more serious and even unexpected. One example? Weight gain. Here’s why.
What is the circadian rhythm and what does it have to do with sleep?
Let’s back up a step. The sleep-wake cycle is controlled by our circadian rhythm, which is a mechanism that uses hormones to maintain the body’s balance by adapting to external and internal stimuli. We can imagine it as a clock that is located in the brain (specifically in the suprachiasmatic nucleus in the hypothalamus) and is responsible for synchronizing other peripheral clocks located at the level of organs and tissues and that control cellular processes, physiological functions, and behaviors over a 24-hour period.
What are the effects of sleeping poorly?
The sleep-wake cycle is one of these peripheral clocks, and the moment it loses synchrony with the others, repercussions can occur on several hormonal axes, including those that control appetite and fat and sugar metabolism. For example, some studies indicate that sleeping less than six hours a night alters the functioning of the thyroid gland (a gland located in the neck, in front of the trachea) and the production of cortisol, the stress hormone. Additionally, it can cause changes to the concentrations of leptin and ghrelin, the hormones that directly control appetite.
The circadian rhythm regulates biochemical reactions according to a day-night cycle, which is useful in anticipating our body’s functional needs, thereby increasing its efficiency
What regulates hunger?
Appetite is regulated by several processes, including the relationship between two hormones called leptin and ghrelin. Leptin is produced by the stomach and adipose tissue and indicates high energy levels in the body. It is called an anorectic because, in order to drive energy consumption, it suppresses appetite at the level of the central nervous system. Ghrelin is its opposite. Also synthesized in the stomach, ghrelin has the opposite effect of leptin on the brain, that is, it stimulates the sense of hunger.
What are the consequences of insomnia?
Chronic sleep deprivation results in alterations in the equilibrium between leptin and ghrelin. More specifically, ghrelin production increases, while leptin production decreases. As a result, you feel hungrier and, when you eat, you take longer to feel full. Sleeping little and feeling hungry increases the occasions for late-night snacks, with a preference – it seems – for high-calorie foods such as cookies and chips. As a result, you tend to eat too many calories and gain weight.
Unfortunately, that’s not all. According to a study published in the journal Nature in 2019, an altered sleep-wake cycle negatively affects the immune system in the gut and predisposes to the onset of inflammatory diseases. It also impairs the control of blood sugar levels (glycemia)-a phenomenon that can become the prelude to metabolic syndromethe metabolic syndrome is characterized by the simultaneous presence of at least 3 metabolic and haemodynamic alterations that represent a high risk factor for the onset of cardiovascular diseases and tumors. and type 2 diabetes if not remedied.
