The ROI of Exercise

Summary

The ROI of exercise 22 Aug, 2025 I workout 4 days a week and I love it. It's the foundation of my morning routine, following spending 45 minutes drinking coffee on the couch and watching the sun come up with Emma. I've been doing this for a few years now and while I struggled (as everyone does) in the beginning, I can't imagine not exercising in the morning now. On the rare occasion that I do skip a workout, I feel it missing throughout the day as a lack of vitality and less mental clarity. Let's perform a thought experiment to work out the return on investment of exercise. For this let's first assume that exercise does nothing else but expand your lifespan (not extend; since it's not just adding frail years to the end but instead injects extra years in each stage of life). We can ignore the effects it has on strength, focus, feelings of accomplishment, and mental health for now. It's well understood that a good exercise routine is a mixture of strength, mobility, and cardio; and is performed at a decent intensity for 2-4 days a week for at least 45 minutes. This could be a combination of weight lifting, yoga, running, tennis, hiking, or whatever floats your boat. This totals about 3 hours a week, or 156 hours per year. If we extrapolate that over an adult lifetime, that's about 8,500 hours of exercise, or about a year of solid physical activity. That sounds like a lot! But when put into the context of life expansion, it's actually an incredibly good deal. There are many studies detailing how any physical activity, from an easy walk all the way up to vigorous exercise a few times a week increases expected lifespan by 3 to 10 years. And none of these studies used lifetime exercisers, just people who exercised regularly in the last 10-ish years. This makes sense, since 80 years ago we were still fighting the second world war, and jogging only entered the mainstream in the 70s. Weightlifting was an even later bloomer, and only becoming cool in the 90s! I speculate that...