A recent study shows that just one night of insomnia promotes weight gain by disrupting fat and muscle metabolism
In our hyper-connected society where there is always something going on 24 hours a day, 7 days a week, more and more people suffer from a sleep deficit. It is estimated that at least 50% of the population sleeps insufficiently (less than 7 hours per night) and/or has poor quality sleep, marked by difficulty falling asleep, periods of insomnia or intermittent awakenings.
In addition to the immediate repercussions of this lack of sleep on the general functioning of the tired person (lack of attention, irritability, reduced productivity), a large number of studies indicate that poor sleep can also promote the development of a range of serious chronic illnesses, ranging from heart disease to certain types of cancer. Sleeping therefore not only serves to rest and recover our energy, but represents a metabolic period that has several important repercussions on the whole organism.
Obesity, metabolic syndrome, hypertension: lack of sleep is expensive
A clue to this important role comes from several observations showing that lack of sleep is associated with an increased risk of many metabolic disorders, including obesity, metabolic syndrome (a combination of hypertension, overweight and dyslipidemia) and type 2 diabetes.
The risk of developing these conditions is particularly pronounced in people who have chronic sleep problems (night workers, for example), but has also been observed in people whose sleep is disturbed for only a few consecutive nights.
According to research on this phenomenon, lack of sleep promotes overweight by causing an increase in hormones that stipulate appetite, by promoting overconsumption of food, as well as by disrupting sugar metabolism. In the latter case, a study showed that young men (18-27 years old) who were sleep deprived (only 4 hours in bed for 6 consecutive days) had a significant drop (30%) in insulin secretion in response to glucose, of the same order as that normally observed in people aged 60 and over.
Adequate sleep is therefore not only necessary for rest, but plays an important role in maintaining normal physiological functions.
Lack of sleep promotes fat accumulation
A recent analysis of the biochemical phenomena altered by the lack of sleep makes it possible to visualize at the molecular level the impact of this deficit on the metabolism.
In this study, the researchers took blood, fat and muscle samples from 15 volunteers on two occasions, either after
a normal night’s sleep or following a sleepless night. They first observed that sleep deprivation caused significant changes in the DNA methylation profile, an epigenetic modification that plays an important role in the control of gene expression. At the level of adipocytes (cells that store fat), these modifications cause an increase in the activity of genes involved in fat storage, while at the level of the muscles, it is rather a degradation of structural proteins that is observed. .
These observations are in agreement with several studies showing that sleep deprivation promotes the accumulation of fat mass and decreases muscle mass in parallel.
Since these changes are already visible after just one sleepless night, one can imagine how repeated lack of sleep can adversely affect metabolism and support the development of numerous pathologies associated with overweight.
Spiegel K et al. Impact of sleep debt on metabolic and endocrine function. Lancets; 354: 1435-1439.
Cedernaes J et al. Acute sleep loss results in tissue-specific alterations in genome-wide DNA methylation state and metabolic fuel utilization in humans. Science. Adv. 2018; 4: eaar8590.