Chronic sleep loss has become more prevalent in modern society, and led to a multitude of negative health effects directly correlated to lack of sleep. Needless to say, sleep is an important part of our daily lives, despite the fact that involves us doing quite literally nothing.
Sleep leaves us unable to forage for food, mate, or run from potential predators – yet we spend roughly one-third of our lives doing it. Therefore, it must fulfill an necessary function in our lives. But what does it do that’s so important?
Researchers from Columbia University have published a new study in PLOS Biology reporting the link between lack of sleep in fruit flies and sensitivity to acute oxidative stress. Oxidative stress is a consequence of excess free radicals in the body, which can damage cells and lead to organ dysfunction. Toxic free radicals – also known as reactive oxygen species – build up in cells from normal metabolism and environmental damage.
In their study, the researchers used a diverse group of short-sleeping Drosophila (fruit fly) mutants. They determined that these insomniac insects all had a sensitivity to acute oxidative stress. This finding matched their suspicions; that if sleep is required for a core function of health, animals that sleep significantly less than usual are likely to share a defect in that core function. If the function of sleep is to defend against oxidative stress, it would make sense that increasing sleep would increase resistance to oxidative stress.
The authors also proposed that, if sleep has antioxidant effects, then oxidative stress might actually regulate sleep itself in a bi-directional relationship. Their findings were in agreement with this proposal, as reducing oxidative stress in the brain through overexpression of antioxidant genes led to reduced sleep in fruit flies. Thus, sleep helps defend the body against oxidative stress, and oxidative stress helps induce sleep.
Many human diseases associated with oxidative stress can also be linked to sleep disorders, including Alzheimer’s, Parkinson’s, and Huntington’s diseases. This means that sleep loss may make individuals more sensitive to oxidative stress – and ultimately these conditions.
Furthermore, disruption of the antioxidant response could also lead to sleep loss and disease pathologies as well. Connections such as these are why it’s important research like this continues, as we attempt to learn more about disease prevention and our own physiology.