I was thinking in general, and realizing that after a number of years in QS, I don’t have a good answer to those questions, so thanks for confirming they’re non-trivial.
Specifically, some interventions I’d like to test have to do with sleep: A/C 67F vs. 75F, taking the Proper supplements, and even kiwis. Problem is that I haven’t found an accurate sleep tracker. Oura gives wildly ranging results (20 minutes vs. 60 of deep sleep) for monotonous days & nights (intermittent fasting, weightlifting in the afternoon EOD (and it’s not about the “other” day), sleep ~2am - 10am), and highly contradictory ones for outliers (e.g. great deep sleep after heavy drinking and dancing until 5am on Halloween night, followed by face planting on a random couch).
