How Modern Light Is Causing Sleep Loss And Making Us Sick

There are many ways in which our Paleolithic ancestors lived completely different lives than we do, in our modern, hyper-digital world.1, 2, 3, 4 Perhaps one of the most interesting factors may be the amount of light which we are exposed to, on a near endless basis.5, 6 And I don’t mean healthy, vitamin D endowing sunlight. I mean artificial, man-made, sometimes cancerous light.7 In fact, modern life typically gives us inadequate exposure to natural light during the day, and also overexposes us to artificial light at inappropriate times (after sunset).8 Study after study has shown this imbalance has possible ties to cancer, diabetes, obesity and other health problems.9, 10, 11

Then there is the troubling fact that a lack of natural light during the day, and too much artificial light at night, causes sleep loss, in addition to the aforementioned metabolic issues.12 As researchers have known since the 1970s, the suprachiasmatic nucleus of the hypothalamus is the central circadian pacemaker in mammals.13, 14, 15, 16, 17 Disruption of the functioning of this nucleus will cause a wide array of physiological and neuronal issues.18, 19, 20

With modern lighting affecting our physiology, it is important to follow steps to help avoid these problems, if one wants to be optimally healthy. Some best practices include dimmer and longer wavelengths in the evening, as well as avoiding the blue light of our computer screens, tablets and smart phones in this time frame.21, 22 Since the estimated prevalence of of sleep-wake disorders in the United States alone is about 50 to 70 million, it is absolutely vital that you prioritize changing your habits, in regards to light exposure!23

Why is the blue light from electronic devices particularly problematic? Quite simply, it suppresses your sleep-related hormone, melatonin, as well as disrupting your body’s natural circadian rhythm.24 Bad news. Those that are particularly susceptible to blue light issues include shift workers, soldiers, firefighters, police officers, and students. It seems like more than a bit of a cruel irony that as we have advanced in technology, we have devolved in our health. Since our circadian rhythms taken the past three billion years to evolve, and smart phones have been around for less than 20 total years, it makes perfect sense that our bodies and brains are not yet adapted to their omnipresence in our modern lives.

It is also vitally important to change the way in which you sleep, or commonly referred to as ‘sleep quality.’ This means a completely dark bedroom, with no light whatsoever, and also a cool temperature. Cortisol dysregulation is another issue commonly seen in today’s modern world, and there are pro-active ways to help combat this problem. Eating a Paleo diet will ensure your hormones stay in line, and will help to effectively regulate your sleep-wake cycle. Insulin highs and lows, energy surges and crashes, and lack of nutrients can all help to disrupt sleep – especially when combined together, and added to unnatural cycles of light exposure.

Combine all of these problems with the fact that sleep loss helps to make you fat, and you can begin to see just how vital proper light cycles are to an optimally healthy life.25 Remember, electric light exposure during the night, leading to altered sleep, also disrupts your circadian rhythm.26 This results in detrimental changes to your hormones, gene expression, markers of metabolism and many other physiological parameters.27, 28, 29, 30, 31  So in conclusion, go home, turn your lights out, and get a good night’s sleep! Your future self will thank you for it!


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This article originally appeared on The Paleo Diet.