Introduction
Sleeping is with no surprise a very important portion of our life. It helps our body rest from a day (or just a time) full of mental and physical effort. However, one may ask what is the appropriate sleep duration our body needs? It is difficult to precisely answer this question as this depends on many factors which are often interrelated. These include own’s circadian rhythm, and environmental stressors such as light. However, it is generally agreed that 8h-night sleep is enough to not only have the necessary rest, but also to help our body have its immunity optimized. And what is better than a good night of sleep for a great mood and an increased attention?
Benefits of a good night of sleep
The appropriate sleep duration decreases mortality. A research, summarizing the findings of 27 studies and counting a total of 1 382 999 participants who were followed-up for 4 to 25 years, looked at the effect of sleep duration on mortality. This research showed that both short sleep duration, defined as less than 7h and long sleep duration defined as more than 8h increase the risk of death by 12% and 30% respectively.
The right sleep duration is good for your heart and cardiovascular system. Another report of 15 studies, including 474 684 participants followed-up for 6.9 to 25 years, showed that short sleep duration (≤ 5h) increased the risk of having or dying from a coronary heart disease and stroke by 48% and 15%, respectively, while long sleep duration (>8h) increased the risk by 38% for coronary heart disease and 65% for stroke.
7-8h sleep is best to prevent type 2 diabetes. A summary of 10 studies, including in total 107 756 participants who were followed-up for 4.2 to 32 years, showed that people who sleep ≤ 5h per night have 28% more risk to develop type 2 diabetes. In this study, the risk was even greater in people who sleep more than 8h as it reached 48%.
8h sleep improves immunity and decreases pain. A clinical trial comparing a group deprived of sleep for consecutive 88h and a group sleeping 8h per night, showed a significant increase in pain intensity, including headache, muscle pain, stomach pain, generalized body pain, and physical discomfort. Furthermore, the study showed that prostaglandin, an inflammatory mediator, increases along the process. Another study showed similar trends with interleukin-6 which also has a role in pain incidence. The study compared a group of participants sleeping 4h per night with a group sleeping 8h per night. Similarly, the inflammation protein C-Reactive Protein (CRP), which is at the same time a predictor of cardiovascular disease incidence, was found to be increased in study participants deprived of sleep for 88h in a raw or sleeping just 4.2h per night when compared to individuals sleeping 8h.
Conclusion
Sleeping more (or even less) than 7-8h per night is not good for health. It increases the risk of inflammation, chronic diseases and death. Sleep well and enough to keep an increased immunity and stay healthy.
References
https://www.ncbi.nlm.nih.gov/pubmed/24891081
https://www.sleepfoundation.org/sleep-topics/what-circadian-rhythm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864873/
https://www.ncbi.nlm.nih.gov/pubmed/21300732
https://www.ncbi.nlm.nih.gov/pubmed/19560866
https://www.ncbi.nlm.nih.gov/pubmed/17910386
https://www.ncbi.nlm.nih.gov/pubmed/14975482
