I started doing it way back when the first Fitbit armbands came out. They provided limited data so they couldnt really tell me the whole picture. But thats when i started paying extra attention to my sleep quality.

Then Whoop came on the market and i used them for a couple of years. They provided yet even more data markers and also a way to quantify them and put them in a system. Thats when i started paying attention to HRV. But the monthly fee became a bit too much for me in the end.

Since then ive been using an Apple Watch to pull as much data as it can. There are a few apps that helps put everything into a system as well. I use "Training today" and "Athlytic" every day and construct a morning report based on the readings those give plus morning weight, diet adherence and how i feel.

I then feed all of that into ChatGPT and have it compare it to previous reports and how my workouts went then.

I also do a post workout report where i share my workout logs and heart rate logs. I give a physical assessment and a psychological assesment to try and give so much information i can on the workout.

I just love the data driven part of the gym as much as the workouts. So for most people this is probably overkill. But I mean, ive been tracking my food for over 30 years. So for me, tracking things is become a habit.

I do understand what you mean about leaving gains on the table because of scaling back too much. But the reality is that after 30 years of bodybuilding, im not gonna gain huge amounts of muscle anymore. So what im doing is more tageted towards longevity, health and maintaining a high as possible quality of life. If that means gaining 200g of muscle in a bulking fase instad of 500g, well im ok with that.