I just crossed a year of using Whoop and spent some time reflecting on what I’ve learned. In case you don’t know, Whoop is a fitness monitor that tracks your heart rate giving you insights on how well you slept, how hard you exerted yourself during exercise, how much your body recovered, etc.

One of my principles is to invest in my health, so it felt worth the cost. I really like that I can wear it on my bicep, rarely have to charge it (once every two weeks), and it doesn’t have a screen.

Here are some things I’ve learned:

Hours of sleep is important

I remember there was a period of a couple of months when I felt perpetually tired. Whoop was showing I had a large sleep debt during this time, a metric that tracks the accumulation of how much sleep you got relative to what you needed. I remember when I started to sleep more (and paid off this sleep debt), I felt more energy during the day. I was no longer drifting to sleep on my subway rides and instead reading books.

The correlation is pretty strong; whenever I feel groggy, it’s usually because I didn’t get the best sleep the night before. I’m now really opposed to red-eye or early-morning flights; I’m willing to pay a premium to avoid them.

I also have noticed that when I don’t sleep properly, my willpower is significantly weaker. If I’m not fully rested, I’m more likely to cave in and eat unhealthy food, get distracted at work, and falter on maintaining habits that I’m building. I also think sleep deprivation makes me less kind and motivated than I strive to be; it’s like I revert to factory settings.

A lot of my beliefs on sleep also come from Why We Sleep, a great book that emphasizes sleep as the foundation for nearly everything - it’s worth a read.

Quality of sleep is important

Quality of sleep is just as important as hours of sleep. I’ve noticed that lowering my resting heart rate really helps sleep quality. Concretely:

  • Drinking destroys sleep quality. This is obvious, but it kind of surprised me just how bad it is. Funny story: someone I know had their Whoop for some time and said it made them feel bad about drinking so they got rid of their Whoop 😅
  • Running or any cardio intensive exercise late in the day can make it really hard to sleep. I once did a long run a few hours before sleeping and I distinctly remember lying in bed unable to sleep; I was so tired, but I couldn’t for the life of me get my heart rate down. I now try to avoid heavy runs at night and don’t run at all within 3 hours of falling asleep.
  • Eating a heavy dinner significantly ruins my sleep. I think this is because your body is spending a lot of energy processing the food. I skipped dinner for a few months, and I had really great sleep during that time. Now, I try to keep dinners smaller and earlier in the night.
  • I sleep in a really cold room, which apparently is good for sleeping. I take a hot shower at night, which I also think helps, but I’m not too sure.
  • I’ve found reading books, playing the guitar, and not using my phone within an hour of bedtime to be useful for lowering my heart rate.

Worse sleep is sometimes worth it

After a few months of having my Whoop, I started becoming a little too obsessive over it. There were moments when I’d be out with friends and think to myself “oh my god my recovery is going to be so low tomorrow” (yes I was that person). It’s good to prioritize my health, but over-indexing on it is probably not the best. In a way, the act of optimizing can itself be suboptimal.

I now treat a worse recovery/sleep as debt. This has a bad connotation, but sometimes, you really do want to take on debt. Having a drink or two and staying up with friends has made me happier and more fulfilled than getting perfect sleep every night. It’s about balance - you just can’t make this trade every day.

These metrics are kind of obvious?

You might think it’s kind of obvious: when you sleep less, you are tired. And you’d be right; I think a lot of these insights aren’t really that deep. Also, some of these metrics might be more gimmicky/less accurate.

I find though that it’s easy to lie to yourself and ignore the importance of sleep and rest. Yes, you can always just listen to your body, but you’re much more likely to follow through if you see concrete numbers. Even if the metrics aren’t fully accurate, it’s at least a good estimation that is better than you guessing.