Lack of Sleep Equals Weight Gain
Did you know that lack of sleep contributes to weight gain?
In a new study, researchers at Uppsala University in Sweden demonstrated that one night of sleep loss has a tissue-specific impact on the regulation of gene expression and metabolism in humans. This may explain how chronic sleep loss impairs metabolism and adversely affects body composition.
Epidemiological studies have shown that the risk for obesity and type 2 diabetes is elevated in those who suffer from chronic sleep loss or who carry out shift work. Other studies have shown an association between disrupted sleep and adverse body composition, in which fat accumulation is increased at the same time as muscle mass is reduced—a combination that in and of itself has been associated with numerous negative health consequences. Previous studies have shown that metabolic functions that are regulated by skeletal muscle and adipose tissue are adversely affected by disrupted sleep and circadian rhythms. However, until now it has remained unknown whether sleep loss per se can cause molecular changes at the tissue level that can confer an increased risk of adverse weight gain.
In the new study, researchers studied 15 healthy normal-weight individuals who participated in two in-lab sessions in which activity and meal patterns were highly standardized. In randomized order, the participants slept a normal night of sleep (more than eight hours) during one session and were kept awake the entire night during the other session. The morning after each nighttime intervention, small tissue samples (biopsies) were taken from the participants’ subcutaneous fat and skeletal muscle. These two tissues were selected to study because they often exhibit disrupted metabolism in conditions such as obesity and diabetes. At the same time in the morning, blood samples were also taken to enable a comparison across tissue compartments of a number of metabolites. These metabolites comprise sugar molecules, as well as different fatty and amino acids.
The tissue samples were used for multiple molecular analyses, which revealed that the sleep loss condition resulted in a tissue-specific change in deoxyribonucleic acid (DNA) methylation, one form of mechanism that regulates gene expression. DNA methylation is an epigenetic modification that is involved in regulating how the genes of each cell in the body are turned on or off, and is impacted by both hereditary and environmental factors, such as physical exercise.
The research group was the first to demonstrate that acute sleep loss in and of itself results in epigenetic changes in the so-called ‘clock genes’ that within each tissue regulate its circadian rhythm.
Further analyses of gene and protein expression demonstrated that wakefulness affected skeletal muscle and adipose tissue differently. A possible explanation for why the two tissues respond in the observed manner could be that overnight wakefulness periods exert a tissue-specific effect on tissues’ circadian rhythm, resulting in misalignment between these rhythms. This is something that the researchers found preliminary support for also in this study, as well as in an earlier study that was similar, but smaller.
In the present study, they observed molecular signatures of increased inflammation across tissues in response to sleep loss. However, we also saw specific molecular signatures that indicate that the adipose tissue is attempting to increase its capacity to store fat following sleep loss, whereas we instead observed signs indicating concomitant breakdown of skeletal muscle proteins in the skeletal muscle, in what’s also known as catabolism. In other words, lack of sleep increased both the body’s ability to store fat and break down muscle.
They also noted changes in skeletal muscle levels of proteins involved handling blood glucose, and this could help explain why the participants’ glucose sensitivity was impaired following sleep loss. Taken together, these observations may provide at least partial mechanistic insight as to why chronic sleep loss and shift work can increase the risk of adverse weight gain as well as the risk of type 2 diabetes.
The researchers have only studied the effect of one night of sleep loss, and therefore do not know how other forms of sleep disruption of circadian misalignment would have affected the participants’ tissue metabolism.
It will be interesting to investigate to what extent one or more nights of recovery sleep can normalize the metabolic changes that we observe at the tissue level as a result of sleep loss. Diet and exercise are factors that can also alter DNA methylation, and these factors can thus possibly be used to counteract adverse metabolic effects of sleep loss.
What Does the Research Mean to You?
When it comes to health and wellness, the importance of sleep cannot be overstated. You, my personal training clients could meet every physical activity and dietary guideline, but if you are not getting enough sleep on a regular basis, it is unlikely that you will be able to sustain your health and wellness goals. As this study demonstrates, a lack of sleep can have a negative effect on body fat, skeletal muscle and blood glucose levels.
Here are a few tips:
- Go to bed at the same time each night
- Reduce screen time usage an hour before bedtime
- Remember, rest and recovery are essential to maintaining a healthy weight and reaping all the intended benefits of your fitness program.
- For more information on how lack of sleep equals weight, contact Maurie Cofman, CMES, CES, TBMM-CES, Personal Trainer, Certified Medical Exercise Specialist, Health Coach and Corrective Exercise Specialist in the St. Louis, Brentwood, and Clayton, MO area.