Two years ago, I did some sort of workout or race on 200 distinct days. Overall, I feel that I lost fitness that year and I definitely gained weight - fat to be more specific.
Last year, I trained 227 distinct days, with a major emphasis on CrossFit. I lost ten pounds of body mass, and perhaps 15 pounds of fat. So, this was enough for me to improve, although the change in training emphasis was also a factor.
All last year, after a poor start to the year, my goal was to work out at least 2/3 of the days in the year. I didn't make it but I still improved my fitness.
So, having turned 50 years old last week, I'm trying to figure out an optimal way to structure my workouts. I enjoy the training I'm doing these days. After so many years of simply running year round and skiing on the weekends in winter, I've really diversified my training. I would say that CrossFit is the focus, but it's not all I do. I like to ride my bike. I still run, but mostly shorter, faster runs than in years past. I like to do heavy lifting sessions on my own, outside of the CrossFit environment. And, I like to ski at a high level on difficult terrain. My students this year are old enough and skilled enough that we are doing exactly that. After skiing on Saturday, I arrived at the mountain tired yesterday. And, we skied hard again.
In past years, I didn't ski as hard on the weekends. So, I could often do 4 or 5 workouts during the work week. These days, that seems excessive.
If I'm trying to balance optimal fitness with minimal injury risk, there must be some "sweet spot" that I can find. But, I don't know where it is right now.
I'm guessing that it's somewhere between 5 and 6 workouts per week. And, no more than 3 of those should be CrossFit. One day should probably be more aerobic than the other days, which tend to be done at high intensity.
For now, I think I'm going to mostly go by feel. I did 6 days last week. This week, I'll do 5 or 6. But, I think it makes no sense to try to train 7 days per week. And when my body tells me it's tired, I think I need to listen.
It's kind of odd that after 27 years of consistent exercise/training, I'm still trying to figure out some optimal plan. Of course, that keeps things interesting as well.