A new study has possibly explained why chronic lack of sleep is associated with an increased risk of overweight and obesity. Researchers from Uppsala University have found a connection between sleep time, exercise and a person’s levels of endocannabinoids. These natural chemical compounds activate the body’s cannabinoid receptors which, much like marijuana, are involved in mood, pain-sensation, appetite, and memory.

Previous studies have also shown that sleep deprivation in healthy participants resulted in overeating, unfavorable food choices, and high-calorie food cravings. Following researchers’ examination of healthy normal-weight participants, they found that endocannabinoids levels were impacted by less sleep in humans, but only before exercise and not after, Medical Xpress reported.

"As previously shown by us and others, sleep loss increased subjective hunger compared with the well-rested state. Given the role of endocannabinoids for promoting hunger and hedonic eating, this could offer an explanation as to why. Meanwhile, we instead saw lower stress ratings after exercise in the sleep deprivation condition, which could also possibly be attributed to the observed endocannabinoid levels following our exercise intervention," senior author associate professor Christian Benedict said in the study, according to Medical Xpress.

"It is noteworthy that when sleep-deprived, the participants saw the same amount of increase in endocannabinoid levels following the acute exercise. Endocannabinoids are thought to confer both the ‘runner's high’ as well as at least some of the neuroprotective effects of exercise,” said lead author of the new study Jonathan Cedernaes, M.D., Ph.D, at Uppsala University, reported Medical Xpress.

“Therefore, this may suggest that even under conditions of chronic sleep loss, exercise may exert similar centrally active, and possibly neuroprotective, properties as under conditions of sufficient sleep. This is an important area for future research as we and others have found that short sleep duration by itself may be harmful to the brain, and in the long run increase the risk of... Alzheimer's disease," he explained.

Source: Cedernaes J, Benedict C et al. Sleep Restriction Alters Plasma Endocannabinoids Concentrations Before But Not After Exercise In Humans. Psychoneuroendocrinology. 2016.

Read more:

Sleep Deprivation Linked To Junk Food Cravings: Endocannabinoid System May Activate Weight Gain

If Blocked Endocannabinoids Trigger Dementia Symptoms, Could Cannabis Prevent Alzheimer’s?