quantified self

All posts tagged quantified self

I’ve been using an Oura sleep tracking ring for six months.

In some ways it’s an impressive piece of technology. It’s small enough to not distract me much, and they went overboard in making the user interface simple. Simple, as in there basically aren’t any controls. I just put it on my finger, and occasionally put it on the charger.

Yet it does a poor job of what I expected it to do: track how long I sleep. It occasionally thinks I’m in bed when I’m not wearing it. If I get up to use the bathroom, it’s hard to predict whether it will decide that’s the start or end of my time in bed.

But the Oura reminded me that “8 hours of sleep” isn’t a good description of what I want – that’s just a crude heuristic for “slept well enough that further sleep won’t improve my productivity / health”. The Oura observes other relevant evidence: body temperature, breathing rate, heart rate, and heart rate variability. I.e. things I ignored because they were too hard to evaluate, rather than because I decided they weren’t important.

If I did a strenuous hike yesterday, it will tell me that 7.5 hours of sleep wasn’t enough, whereas if I’d spent yesterday relaxing, it might have told me that 7 hours was plenty, and that I should be ambitious.

It’s somewhat obvious that I need more sleep when a cold raises my body temperature. The Oura convinced me that there’s a much more general pattern of above average body temperature indicating an increased need for sleep.

I’ve tried comparing the Oura’s heart rate variability measurements with those of the emWave2, and I couldn’t see much correlation. I’m inclined to trust the emWave2 more, but I’m not aware of good evidence on the subject.

The Oura also helps track exercise, at least for hiking (it doesn’t seem to do much for weightlifting, but most of my exercise comes from walking/hiking). It reports slightly less calories burned than what I calculate from a cheap Garmin GPS and this calculator. I’m unsure which of those 2 measures is more accurate. If I were only using the GPS to measure calories burned, I’d give up on the GPS, because the Oura doesn’t have problems such as poor reception, or me forgetting to turn it on or off at the start and end of a hike.

It said I slept 3 hours on a red eye flight. My subjective impression was that it was somewhat debatable whether any of that ought to be classified as sleep. But what do I know? I have some evidence that I can sleep without being aware of sleeping (mainly from people reporting that I was snoring, at a time when I thought I was awake and not snoring).

My ring isn’t quite the right size for my ring finger. I ordered it based on prior information about what ring size worked for me, rather than using Oura’s measuring procedure. I’ve ended up wearing on the middle segment of my middle finger instead. That’s works well enough that the difference seems unimportant.

See this comparison with several alternatives for a more detailed analysis.

Mostly, the Oura simply reassured me that I don’t have significant sleep problems, other than the times when it’s obvious that I took too long to fall asleep, or woke up too early. I suspect that the Oura would have been moderately valuable if I had had sleep problems that were hard for me to detect.

Book(?) review: Microbial Burden: A Major Cause Of Aging And Age-Related Disease, by Michael Lustgarten.

This minibook has highly variable quality.

Lustgarten demonstrates clear associations between microbes and aging. That’s hardly newsworthy.

He’s much less clear when he switches to talking about causality. He says microbes are the root cause of aging, and occasionally provides weak evidence to support that.

I still have plenty of reason to suspect that much of those associations are due to frailty and declining immune systems, which let microbes take over more. Lustgarten doesn’t make the kind of argument that would convince me that the microbe –> senility causal path is more important than the senility –> microbe causal path.

He has a decent amount of practical advice that is likely to be quite healthy even if he’s wrong about the root cause of aging, including: eat lots of leaves, green peppers, mushrooms, and use low pH soap.

One confusing recommendation is to limit our protein intake to moderate levels.

He provides a nice graph of mortality as a function of BUN (see here for more evidence about BUN), which hints that we should reduce BUN by reducing protein intake.

He also notes that methionine restriction has significant evidence behind it, and methionine restriction requires restricting protein, especially animal proteins.

Yet I see some suggestions that protein (methionine) restriction is likely only helpful in people with kidney disease.

My impression is that high BUN mostly indicates poor health when it’s caused by kidney problems, and doesn’t provide much reason for reducing protein consumption, and least in people with healthy kidneys.

Lustgarten has since blogged about evidence (see the 7/11/2018 update) that higher protein intake helps reduce his homocysteine.

I have also noticed a (noisy) negative correlation between my protein consumption and my homocysteine levels. But that might be due to riboflavin – when I reduce my protein intake, I also reduce my riboflavin intake, since crickets are an important source of riboflavin for me. So I want to do more research into dietary protein before deciding to reduce it.

The book is too quick to dive into technical references, with limited descriptions of why they’re relevant. In many cases, I decided they provided only marginal support to his important points.

Read his blog before deciding whether to read the minibook. The blog focuses more on quantified-self-style reporting, and less on promoting a grand theory.