By Virginia Gurley, MD, MPH
MB (Marc Braman, MD, MPH):
“Sleep is Key to Physical Health – Part 2”. Again, thank you, Dr. Gurley.
In session 1, we talked about the importance of sleep for your heart, blood pressure, weight, metabolism, and risk for cardiovascular and metabolism related diseases. What are some other ways that sleep affects our physical health?
VG (Virginia Gurley, MD, MPH):
Another key area where sleep affects physical health is how it supports repair and replacement of damaged cells. When cellular repair and replacement are not working properly because of poor sleep, the effects seem to be slower recovery from intense exercise, slower healing after surgery, high risk for some cancers, and possibly shorter overall lifespan.
So basically not getting enough sleep decreases the body’s ability to heal itself when genes, cells, and tissues are damaged by the wear and tear of living.
Exactly, and the wear and tear of living might be from the muscle inflammation that happens after intense physical activity like athletic training or running a marathon. Or the wear and tear might be damage to the genes in your skin from being out in the sun too long. Or another example is your body’s ability to recognize and kill rogue cells that would otherwise become a tumor or cancer.
Sounds like sleep plays a really big role in repairing the body and keeping us alive! How does this work?
Well there’s a lot we still don’t understand about how sleep affects repair of genes and cells, but quite a few studies show that melatonin improves many cell repair activities, especially related to tumor cells. And since sleep is when the body releases melatonin, that is one of the ways sleep helps keep us alive and healthy.
That’s a really big role! Are there other ways sleep helps the body repair and replace cells?
Yes, another way has to do with how sleep and the immune system work together. Our immune system makes groups of substances called interleukins, cytokines, and tumor necrosis factors, and these are related to inflammation. And some of these substances increase cell damage and the growth of tumor cells. So studies have found that short sleep is linked with having higher levels of the cell-damaging and tumor-growing immune substances that cause inflammation.
Interesting. Has anyone studied using sleep to help treat cancer?
Yes, there’s a study where cancer patients were given the usual recommended chemo therapy, but half the patients also followed very specific sleep-wake, light-dark, and eating routines that really enhanced their sleep. And those patients lived much longer than the other group that only received chemo therapy.
Wow, I’m going to be really interested to dig into the details of that study myself! Since sleep is so important to something as basic as the body repairing itself, it seems like people who sleep 7-8 hours each night would live longer. Has this question been studied?
Coming at the question from the other end, studies have shown that sleeping less than 6 hours each night is linked with having a shorter life. And then other studies have shown that when people who sleep 7-8 hours each night do get cancer, their tumors tend to be much less dangerous or aggressive.
So, no matter which way we look at it or cut it, sleep is hugely important for our health. It’s when our body heals and repairs, and it keeps working at our best.
Thank you so much, Dr. Gurley.
Thank you, Dr. Braman.
Circadian Rhythm Disruption in Cancer Biology. Savvidis C, Koutsilieris M. Mol Med. 2012;18: 1249-1260. doi:10.2119/molmed.2012.00077.
Sleep Loss as a Factor to Induce Cellular and Molecular Inflammatory Variations. Hurtado-Alvarado GH, Pavon L, Castillo-Garcia SA, et al. Clinical and Developmental Immunology. 2013; 801341. doi:10.1155/2013/801341.
Skin surface temperature rhythms as potential circadian biomarkers for personalized chronotherapeutics in cancer patients. Scully CG, Karaboue A, Liu W-M, Meyer J, et al. Interface Focus. 2011. 1: 48-60. doi:10.1098/rsfs.2010.0012.