Optimizing sun exposure

For most of my adult life I carefully limited my sun exposure. More recently—after discovering that the more sun exposure I got the better I felt—I’ve been trying to get as much as I could without getting burned. Just lately I’ve been groping towards something more nuanced.

Back in maybe the 1980s I briefly tried to follow the advice of dermatologists to never go out without sunblock. That didn’t work well—inevitably there would come the day when I was unexpected out in the sun longer than expected, and (not having built up a protective tan) I’d end up burned.

After that, for a decade or two, I came up with some simple rules: Unlimited sun before 8:00 AM and after 5:00 PM, but I’d aim to get 20 minutes of mid-day sun. If I was going to get more than that, I’d wear sunblock, but I tried to get that much sun every sunny day. That worked pretty well—I’d get enough of a tan to provide some protection on those days that I was unexpectedly out in the sun.

That schedule, of course, fell out pretty much automatically from working at a regular job. I stuck with it even after I wasn’t working at a regular job because it worked pretty well.

For various reasons, such as needing to take very long walks to train for our big Kal-Haven trail walk, I started spending more time out in the sun, and began to observe that the more time I spent in the sun the better I felt, leading me to get what was probably more sun than is really wise.

Since recently running into the idea that certain frequencies of red and near-infrared light are good for your skin and deeper tissues, I’ve been prompted to think about all this in a more systematic way, and have been trying to come up with a plan that maximizes the benefits while reducing the harm caused by sun exposure.

I’m still in the research stage, but here are the early changes that I’m making:

First, I’m reducing the amount of mid-day sun I’m getting. I’ve been going for around 40 minutes (as much as I can get without risk of burning), but I’m bringing that back to around 20 minutes. Still enough time to make plenty of vitamin D.

Having gotten the amount of mid-day (2:27 PM) sun exposure I wanted, I moved the rest of my walk into the woods.

Second, I’m replacing that 20 minutes of mid-day sun with 20 (or more) minutes of sunlight during the period that the UV index is between 1 and 3. (This time of year, where I live, that’s maybe 7:30 AM until 9:00 AM.) My hope is that part of the reason more sun makes me feel better is the red light (rather than the UV), and that morning and evening sun can provide those frequencies.

Taken during at 8:59 AM during a walk in the prairie.

Third, I’m trying to get some very early (dawn) sun exposure. This is specifically for the effect early morning light has on the circadian rhythm.

Early morning (6:53 AM) sun over the Lake Park/Winfield Village prairie.

Only in the middle of writing this did I realize the extent to which I’ve come back to what I did for most of my working years—except that instead of having to squeeze my morning sun exposure into the time I spent crossing the parking lot, now I can extend it to 20 minutes or longer, and combine it with a proper walk in nature for some sweet, sweet vitamin N.

The sad truth about technology writers (sleep-tracking edition)

For an article in the New York Times, technology writer Brian X. Chen wore a sleep-tracker for a couple of weeks. He reports:

Ultimately, the technology did not help me sleep more. It didn’t reveal anything that I didn’t already know, which is that I average about five and a half hours of slumber a night. And the data did not help me answer what I should do about my particular sleep problems. In fact, I’ve felt grumpier since I started these tests.

Source: The Sad Truth About Sleep-Tracking Devices and Apps

Breaking news: Looking at your power bill every month does not cut your electricity consumption! Checking your speedometer does not slow down your car! Tracking your spending does not make you rich!

I’ve been using a sleep tracker (the Oura ring) since December. Neither wearing the ring nor checking the reports I get has increased the amount of sleep I got. However, I have learned a lot about how to get more and better sleep.

Probably the most useful thing I’ve learned is that the standard advice that you should have supper at least three hours before bedtime isn’t sufficient for me: I sleep much better if I finish supper at least four hours before I lie down to go to sleep.

That’s actually a specific example of my larger point: A sleep tracker makes it easy to run little experiments and quickly see the results.

My intuition as to whether I got a good night’s sleep is an excellent guide (as I suspect it is for most people). But even a good intuition isn’t always enough to run a good experiment, and this is an example of that. Although the Oura ring’s report isn’t better than my own intuition, it provided some specific information that led me to that particular insight: On days when I had a late supper, my sleep quality was quite poor for the first couple hours of sleep, a pattern that I didn’t see on days when I had an early supper.

I’ve used it to run other experiments. For example, it appears that I get more deep sleep on days when I have only one drink than on days when I have two. (This is very sad news, and will have to be confirmed by many more experiments before I use it to modify my behavior—but at least I can run the experiments.)

After a rough patch last fall (which is what prompted me to order the Oura ring), I’m actually sleeping pretty well now, so I’m not aggressively running new experiments to try and improve my sleep. I am, however, paying attention when a natural experiment presents itself. For example, we generally sleep with the windows open all summer. Over the next two nights that will probably produce sleeping temperatures in the 70s, whereas over following several nights I’ll get to enjoy sleeping temperatures in the 60s. I know from experience that the cooler temperatures will produce better sleep, but the Oura ring will give me detailed metrics that will let me investigate if there’s an optimal temperature—information that may be very useful in the winter for deciding how to adjust the thermostat.

That’s the value of the ring for me: It lets me run experiments of specific sleep interventions, and gives me results that are more fine-grained than just a general sense as to whether I slept well or not.

Here’s one more natural experiment. I observed decades ago that I need more sleep in the winter than I do in the summer. I can now put a couple of numbers on that.

Here’s my total sleep each day in January and February this year. The report from the Oura ring lets me see that I averaged 7 h 50 min of sleep each night:

Here’s my total sleep each day from June 1st through last night. I can see that I averaged 7 h 03 min of sleep each night:

I’ve perceived each period as being roughly equally good in terms of getting “enough” sleep, so I’m inclined to think of the 47 minute decrease in sleep as being a decrease in the amount of sleep I need when the days are long and sunny and I’m getting plenty of fresh air and exposure to nature. In the winter I need darn near 8 hours of sleep per night. In the summer I can get by fine on just over 7.

That information doesn’t make me sleep better, but it’s still useful (even if it just confirms something I’ve known for a long time).

In other breaking news recently published in the science journal “Duh!”: Stepping on the bathroom scale every morning neither increases your muscle mass nor reduces your fat mass!