I have long said that good health begins with good sleep. I came to this conclusion when I improved my sleep a great deal and at exactly the same time stopped getting obvious colds. I concluded that better sleep made my immune system work better. At the 2012 Ancestral Health Symposium, in Los Angeles, Rob Wolf said something similar about the centrality of sleep: “If a person sleeps well, you can’t kill them. If they sleep badly, you can’t keep them alive.”
Mainstream health researchers, on the other hand, haven’t figured this out. James Watson, the co-discoverer of the structure of DNA, in a recent paper about how to fight cancer, wrote this:
Long known has been PERIOD 2 (PER2) involvement as a clock protein at the heart of the circadian rhythms of higher animal cells. Later, quite unexpectedly [emphasis added], PER2 was found to function as a tumour suppressor, with the absence of both its copies causing the rate of radiation-induced cancers to rise.
When PER2 is absent, circadian rhythms disappear and sleep becomes very fragmented, spread out over the whole day. When you sleep better (which usually means more deeply), your immune system works better band does a better job of suppressing tumors. There is plenty of other supporting evidence. For example, in 2012 two studies found sleep apnea associated with higher cancer rates. The PER2 evidence is especially good at establishing cause and effect.