Category: Tips and Guidelines

What Everyone Should Know About How Your Skin Helps You Sleep

By Virginia Gurley | Sep 02, 2010

What Everyone Should Know About How Your Skin Helps You Sleep

Most people are aware of the basic do’s and don’t before bedtime that affect sleep: Do things that are relaxing like taking a warm shower, pleasure reading, listening to music, stretching, or meditating; don’t do things that are stress inducing like exercising strenuously, eating or drinking caffeine, working, thinking or talking about stressful topics.

What is not widely known, and strange as this may sound, the temperature of your skin is critical to being able to fall asleep quickly and stay asleep through the night. Here is what happens and how skin temperature affects your sleep.

  • An hour or two before your typical bedtime, the skin of your hands, arms, legs and feet should start getting significantly warmer due to increased blood flow. 
  • With this increase in skin blood flow and warmth, body heat is given off to the air surrounding the skin, causing your core body temperature to decrease gradually through the night.
  • The increase in skin temperature, along with the parallel night time increase in melatonin, is what causes drowsiness and the rapid onset of sleep when you turn out the lights.
  • When skin blood flow and warming cannot increase due to vasoconstriction (narrowing of the blood vessels), getting to sleep will take longer, staying asleep can be difficult, and how much restorative slow wave sleep and learning-dependent REM sleep you get can be decreased. 

Some things that can cause your blood vessels to narrow when they should be dilating for sleep include high adrenaline levels due to stress, low blood pressure due to dehydration, a medical condition called vasospastic disorder, and a low core body temperature due to eating something very cold like ice cream.

So, here are simple things I do to help my sleep-related skin warming and improve my sleep.

  • If my feet or legs are cool or cold at bedtime, I wear socks to bed and/or take a warm shower.
  • I drink plenty of non-caffeinated beverages during the day and early evening so I am well hydrated by dinner time.
  • When I’ve had a stressful day or feel wound up in the evening, I try to get moderate exercise in the late afternoon or early evening. I use the stress reducing activities described above to help decrease night time stress too.
  • I avoid drinking and eating things that are very cold in the hour before bedtime.
  • I keep the temperature of my bedroom and my bed cool enough that my skin can give off heat, but warm enough that I don’t feel chilled.

If you are familiar with the impact of skin temperature on sleep and have any tips or comments to share, your contribution to exploring this topic is greatly appreciated.

How and when your core body temperature cools at night can also affect your sleep, but I’ll save that topic for a future post.


Maximizing the Benefits of Sunlight without Wearing More Sunscreen

By Virginia Gurley | Aug 10, 2010

Maximizing the Benefits of Sunlight without Wearing More Sunscreen

Here on the 41st parallel, it’s late August, and the days are noticeably shorter. The daily Ultraviolet Index forecasts I get from the Environmental Protection Agency also reflect the waning of summer as the peak UV levels are starting to decline. 

What this means for maximizing the health benefits of sunlight is that I can spend more hours during the morning and late afternoon in direct sunlight without getting potentially damaging levels of ultraviolet (UV) radiation.

Not to minimize the realities of sunlight induced skin damage, but getting some level of UV radiation, especially UVB (wavelengths 280-340 nm), is critical to the health of our bones, and possibly to the health of our immune system, through the production of vitamin D in the skin. Sunscreen blocks UVB and vitamin D production. Because people of color have more melanin in their skin, and melanin reflects UVB, up to 4 times more UVB is needed to produce health sustaining levels of vitamin D than for white people.

Given the growing number of research studies demonstrating vitamin D receptors in many different parts of the brain, we may soon learn that Vitamin D also affects mood and nervous system health.

One of the paradoxes, or yet to be untangled puzzles, of sunlight, UV radiation and health is that low to moderate intensity UV may actually protect against skin cancer if there is a slow, gradual increase in UV levels.

The mechanisms for this emerging potential protective effect of low-moderate intensity UV are several. First there is the simple UV reflective effect of melanin, which increases skin pigmentation, or tanning, in response to gradual increases in UVB. Second, human skin contains all the component parts needed for melatonin synthesis (yes, the same melatonin that helps regulate sleep and circadian rhythms), and laboratory studies have shown that melatonin can inhibit the development of cancerous tumors. The catch is, production of skin-based melatonin seems to require prior, gradual exposure to bioactive (ie low to moderate) levels of UVB radiation.

The pattern I see across these studies is that low to moderate levels of UV radiation from morning and late afternoon sunlight trigger built in mechanisms that help protect against the damaging effects of higher intensity UV radiation. Sunlight is much more damaging when we expose ourselves to sudden, dramatic increases in exposure - like going from being an office mole to a vacationing beach bum in one day, or like spending an entire weekend day in direct summer sun when all your weekdays are spent indoors.

So, here is my approach to maximizing the health benefits of sunlight:
During summer, I try to get as much early morning and late afternoon sunlight as I can.
I use EPA UV Alerts (sent daily to my email and calculated specifically for my geolocation) to be aware of days when UV intensity is going to be high and when UV starts to trend down. Because I think the balance of research shows that moderate intensity (ie bioactive) UVB is beneficial to health, I’m more liberal about my exposure to mid-range UV, but when the UV Index is forecast to be above 7 or 8, I heed their precautions.

When I’m outside during midday in the summer, I stay in the shade as much as possible.

I avoid prolonged direct midday summer sunlight, especially if I haven’t been able to get much morning or late afternoon sun during the prior few days.

If I’m going on a trip during which I’ll be getting a lot more sun exposure, like if I’m going to climb a 14er or going on a sun and sand vacation, I try to increase my sun exposure where I live for a few days before my departure and gradually increase over my sun exposure over several days when I reach at my destination. This is especially important when traveling to the tropics in winter or early spring (wish I could say I’d done that recently).

During winter I use different strategies to balance the hazards and benefits of UV radiation and sunlight, but I’ll save that list for a later post.

If you take medications or have medical conditions that can affect your sensitivity to sunlight, please talk with your personal healthcare professional before increasing your exposure to sunlight.

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