You may not have to deal with only daytime fatigue and sleepiness, yawning, a “fuzzy” head, depressed mood and clumsiness, after working late hours or completing a night shift. Getting “extra fat” has emerged as a real possibility, following acute sleep deprivation. This is according to a study spearheaded by Jonathan Cedernaes, a circadian researcher at Uppsala University, Sweden.
According to the researchers, “Chronic sleep loss, social jet lag, and shift work—widespread in our modern 24/7 societies—are associated with an increased risk of numerous metabolic pathologies, including obesity, metabolic syndrome, and type 2 diabetes. Even minor weekly shifts in sleep timing, or as few as five consecutive nights of short sleep, have been associated with an increased risk of weight gain in healthy humans.”
Seventeen (17) participants, were enlisted for this study, with fifteen (15) successfully adhering to the sleep protocol of the study – which was one night of sleep loss (overnight wakefulness) and one night of normal sleep, without physical exertion of any sort, but with freedom to engage in sedentary-level activities. Study participants “self-reported” normal sleeping habits (7-9 hours of sleep per night) and normal sleep quality (as assessed by the Pittsburgh Sleep Quality Index Score ≤5). The participants also “self-reported” good health and were free from chronic medical conditions and chronic medications. These assessments were carried out by a medical doctor, via a questionnaire.
Biopsies were obtained from the subcutaneous adipose tissue and the skeletal muscle tissue of the participants, both after one night of sleep loss and after a night of normal sleep. The ensuing results were quite interesting, with contrasting changes in both the skeletal and adipose tissue.
“Many of the adverse effects attributed to sleep loss and circadian misalignment might arise due to tissue-specific metabolic perturbations in peripheral tissues such as skeletal muscle and adipose tissue. Recurrent sleep loss combined with moderate calorie restriction in humans increases the loss of fat-free body mass, while decreasing the proportion of weight lost as fat, suggesting that sleep loss can promote adverse tissue-specific catabolism and anabolism,” the researchers added.
Skeletal muscle tissues, experienced a nose-dive in Lean Body Mass (LBM) – which is the total weight of a person’s bone and muscle minus their fat weight. Whereas, adipose tissues, fat storage tissues in the body, experienced increased levels of proteins linked to adipogenesis – a cell-differentiating process that culminates in the formation of fats. In simple words, the body skeletal muscles suffered a shrinkage in mass, while the body adipose tissues experienced raised levels of fats – gain of fat mass.
Summarily, curtailed sleep promotes weight gain and loss of lean mass in humans.
While previous studies provided a hint regarding the connection between obesity and sleep deprivation, this link was closely related to changes in lifestyle. Now, researchers have shown a physical mechanism that is responsible, or at the very least partially responsible for this connection.
Despite the outstanding revelations of this study, it only provided a limited insight into acute sleep loss and the corresponding effects of weight gain. The study was a short term intervention, which focused only on male Caucasians, leaving a gaping hole of uncertainty regarding tissue-specific changes in response to acute sleep loss in different age groups, females or other ethnicities. The effects of chronic sleep deprivation, was also not captured in the study. But for now, it is safe to say that sleep is not something you should be deprieving yourself of.