If you follow my blog, you’ll know that I’ve already written a couple of posts about sleeping. It’s a subject that is near and dear to me as I’ve always been a lousy sleeper. When my head hits the pillow, my “monkey mind” takes over and keeps me awake. So I’m naturally drawn to books that offer insights about how I might improve.
Lights Out: Sleep, Sugar, and Survival by T.S. Wiley (with Bent Formby, PhD) provides interesting insights on this subject matter. Wiley is an anthropologist whose research on human physiology gives hearty consideration of our evolutionary history. She’s also meticulous in combing through and documenting studies by luminaries in the field. (She devotes roughly a third of the book to endnotes and bibliography!)
She notes that in 1910, the average adult slept 9-10 hours per night. Now, we’re lucky to get 7 hours per night. And when we don’t get enough sleep, we’re more likely to be fat, hungry, sickly, hypertensive, and prone to cancer and heart disease. (Yikes!) Here’s why…
As humans, we are hard-wired to store fat when exposed to long days, short nights, and a diet rich in sugars. Our bodies think it’s summer – a time to add some extra padding to get ready for sparse food supplies in winter. The combination of less sleep and increased sugar consumption revs up our appetites, thereby ensuring that we grab all the calories we can while the getting is good. As we bulk up, our livers also transform excess sugar into cholesterol to help keep cell membranes from freezing when the low temperatures settle in.
Shorter nights also result in less melatonin production which dampens immune function. Melatonin is a powerful antioxidant. Moreover, according to the NIH, it takes three-and-a-half hours of melatonin secretion before you see prolactin. You need six hours of prolactin production to maintain immune T-cell and beneficial killer-cell production. A fall-off in production may not be an issue during the warm summer months, but it IS a problem when the cold and flu season hit. And, of course, it’s all the more an issue given the modern day exposure to carcinogens.
We need healthy endothelial cells to control clotting, cellular overgrowth, fat metabolism, and blood pressure. We harm endothelial function by:
- Chronically high cortisol (caused by too much stress)
- High levels of endotoxins (caused by insufficient sleep)
- High homocysteine (caused by too much light)
When humans created artificial light, we threw thousands of years of evolutionary biology out of whack. We no longer have seasons of long days and short nights followed by short days and long nights. With lights, TVs, computers, and all manner of electronic devices on, we think it’s always summer. So we keep storing up for a season of hibernation that never comes. And that’s how we wind up overweight, over tired, and prone to illness.
The solution: Eat foods that align with seasonal production in your local area. Meditate, do yoga, or whatever to relax and ease into sleep. Keep house lights at low intensity after dark. Wear rose or amber glasses to block blue light. Live in total darkness for nine-and-a-half hours per night for at least 6-7 months of the year.