Pseudo-Scientific Longevity Estimator

Many people think sleep is a longevity factor. I'm not convinced (yet).

My view on sleep is somewhat complex, but in the current climate, I end up being a bit of a renegade. Everyone talks about the importance of sleep, but there's a ton of misinformation out there. A lot of popular information is hype and has created a culture in which many people just *can't believe* that sleep isn't a mortality factor. But, consider this.

The main, commonly cited studies are simple surveys asking people how long they slept on average. We're still waiting on a new generation of studies using sleep tracking data. But even in these studies, most of them show a u-shaped curve (with gender differences - women seem more resistant to the effects of short sleep than men). citation.

You can also check out this meta-analysis showing how small the likely effect size is, especially for short sleep. citation.

As you can see, while those studies did show a correlation (NOT causation) between shorter sleep and mortality, it wasn't huge - the real huge effect was between *long* sleep and mortality. And, these studies aren't randomized or controlled, like so many longevity topics, so there's the constant issue of confounding. Here's a study showing that once you adjust for physical activity, the supposed mortality/longevity issues around sleep disappear. citation.

Now, where the data for sleep seems more interesting is its effect on muscle building and the importance of sleep for developing muscle and strength. So even though sleep contributes, the real *metric* to track isn't sleep itself, but muscle - if you aren't sleeping well, but you're still able to develop muscle, then in my opinion, sleep itself isn't a mortality factor.