Although the mysteries surrounding sleep are still being uncovered by scientists, we do know that sleep is crucial to our daytime functioning and is vital for processes such as learning and consolidation of memories. Unfortunately, we often fail to get enough sleep even when we know how important it is. Trying to compensate for poor sleep by sleeping more on the weekends or drinking stimulants like coffee just to stay awake can actually end up doing more harm than good. Failing to get good quality sleep can lead to reduced energy, mood fluctuations, irritability, poor stress management, difficulty problem solving, and a lack of creativity just to name a few.
Because research demonstrates a link between sleep regulation and epigenetic mechanisms such as DNA methylation and histone modifications, understanding these connections not only can give us insight into the formation of sleep disorders such as insomnia but they can also give us new reasons to improve our own sleeping habits and hopefully improve our health in the process.
In the spirit of National Sleep Awareness week, below are 3 ways epigenetic mechanisms are thought to be connected to sleep which may help convince us to try harder for those very important Zzz’s. Besides, there’s only so much coffee one can drink in a day…
1. Sleep Epigenetically Improves Immunity
DNA methylation, perhaps the most widely recognized epigenetic mechanism, is implicated in the connection between sleep and the body’s ability to fight off infections and diseases. Research in the American Journal of Respiratory Critical Care Medicine showed that DNA methylation was increased in children suffering from OSA, or Obstructive Sleep Apnea (Kim et al., 2012). This sleep disorder occurs when throat muscles intermittently obstruct the airways throughout the night, impairing breathing as well as sleep quality. In their study, the scientists discovered that increased methylation levels were linked to an increased systemic inflammatory response as well as organ vulnerability.
The research team found that an increase in DNA methylation levels of FOXP3 (Forkhead Box P3) – a gene that regulates expression of T regulatory lymphocytes – was greater depending on the severity of OSA in the children. Methylation of this immune response-regulating gene was also correlated with increased levels of high sensitivity C reactive protein, which is associated with adverse health outcomes, and the myeloid-related protein 8/14 complex, which plays a role in the body’s inflammatory process.
With these results in mind, it appears getting proper rest epigenetically benefits our immune and metabolic functioning. Spending a little extra time in bed sleeping to prevent a sickness definitely seems better than spending time in bed trying to overcome it!
2. Reduce Stress for Better Rest
It is thought that sleep disorders such as insomnia might be caused by the combination of acute stressors and predisposing risk factors. According to the National Institute of Neurological Disorders and Stroke, frequent or chronic insomnia affects about 60 million Americans a year and almost everyone will suffer from occasional short-term insomnia. Because epigenetic mechanisms such as DNA methylation have previously been implicated in the regulation of our response to stress, improving our ability to cope with stress may epigenetically help to improve our sleep and even decrease our chances of developing insomnia in the long-run.
Recent research shows that histone modifications occur in the hippocampus as a result of acute stress, specifically hindering hippocampal neurogenesis via acetylation of histone H3K9. This may impair our ability to get a good night’s sleep, according to Palagini et al. (2013). The researchers hypothesize that disrupted sleep occurring over a long period of time may act as a chronic stressor itself that supports and maintains insomnia. Although further research is needed, it is possible that extended sleep disturbances could epigenetically perpetuate and sustain insomnia through histone modifications and the stress system (Palagini et al., 2013).
Since evidence supports an epigenetic connection between shut-eye and stress, we could improve our sleep and even stave off insomnia by mitigating daily stressors and taking the time to relax and unwind.
3. Sleep to Reduce Cancer Risk
Impaired sleep causes serious disruptions to a crucial regulatory process in our body known as the circadian clock, or our internal 24-hour sleep-wake cycle. Circadian rhythms respond primarily to light and dark cycles and consist of mental, physical, and behavioral changes. There is evidence that the speed of the circadian clock is controlled by RNA-methylation-dependent RNA processing and now countless studies connect the desynchronization of the circadian clock to tumor development and cancer progression.
For instance, one study looked at whether exposure to light at night and the resulting decrease in melatonin could cause tumors to grow. They found that mice that were exposed to light during nighttime – which stifles the production of melatonin and disrupts molecular circadian rhythms – experienced an increase in tumor growth. According to the researchers, this tumor growth was reversed by melatonin through the epigenetic mechanism of global DNA methylation (Schwimmer et al., 2014). These results indicate that DNA methylation can be modulated by sleep-wake behaviors and, in this case, exposure to light can impact global DNA methylation, melatonin production, and ultimately cancer development.
Not getting enough rest or disrupting your body’s natural sleep rhythm could also lead to epigenetic changes to certain genes linked to immunity and tumor growth. According to another study by Qureshi and Mehlerm (2014), people who were exposed to long term shiftwork had significant alterations in the levels of DNA methylation associated with circadian gene loci, immune system- and inflammation-related gene loci.
Overall, these studies illustrate that sleep and epigenetics go hand-in-hand. Improving sleep can help to improve our immune system and even decrease our risk of developing cancer. With more epigenetic research on the horizon, we can hope to gain further insight into the exact mechanisms that influence our quality of sleep and the health benefits we gain as a result of sleeping well.
If you’ve been inspired to put down that sixth cup of coffee and focus on ways to improve your sleep quality and overall quality of life, head over to the National Sleep Foundation for tips on catching more Zzz’s!
*Disclaimer: The points made herein represent a speculative opinion of the author based on related scholarly publications on animal and human studies.
Palagini, L., Biber, K., Riemann, D. The genetics of insomnia – Evidence for epigenetic mechanisms? Sleep Medicine Reviews. 2013.
Kim, J. et al. DNA Methylation in Inflammatory Genes among Children with Obstructive Sleep Apnea. American Journal of Respiratory Critical Care Medicine. Feb 2012.
Qureshi, I. & Mehlerm, M. Epigenetics of Sleep and Chronobiology. Curr Neurol Neurosci Rep. 2014. 14:432.
National Institute of Neurological Disorders and Stroke. Brain Basics: Understanding Sleep. July 2014. Web.
Schwimmer, H. et al. Light at night and melatonin have opposite effects on breast cancer tumors in mice assessed by growth rates and global DNA methylation. Chronobiology International. Feb 2014.