I'm currently doing 5 days a week on a treadmill with approximately a 60lb backpack. I vary the workouts based on incline vs speed, but I rarely get too much above 4 MPH. I'll do this for about 25-40 minutes as a warmup for some kettlebell swings, cleans, pushups, jump rope, etc. It's just something I can do daily within a few feet of my desk. During my kids' soccer season, I'll also get one or two 1.5 hour sessions per week with a 20-30 lb weight vest. On the weekends I'll usually do a 3-4 exercise weight workout (no more than 40 minutes) and sit in the sauna for a bit.

I don't really have a "plan" or any specific goals for my training other than challenging myself and keeping healthy.

Question: should I vary the weight vs time vs speed for my treadmill work for recovery purposes? Am I doing too much? I'm 41, M, in generally decent shape.