[hermitdev]

I can attest to this. In my mid 20s, I used to hit the gym for 2-3 hours M-F (50/50 cardio and weights per day) and then biking for 5-6 hours over the weekend.

The exercise was a great stress relief for me, and I went from 165 lbs to about 215 lbs over 3 years, all lean muscle mass. Felt great. Was biking thousands of miles per year, running about 4:30 mile on the treadmill, and squatting 2x my bodyweight. I had a resting heart rate of around 45 bmp.

Then, I got hit by a car while on my bike (guy ran a stop sign and and clipped my rear wheel and seat stay). Destroyed my bike; the carbon fiber frame was cracked, carbon pedals ruined and my handle bars were messed up. I also racked up $20k in ER bills that his insurance paid. I dont know how much the X-ray, MRI and orthopaedic visits cost (his insurance had accepted responsibility at that point, and I never saw a bill). I didnt break any bones, but strained almost all ligaments in both knees. The accident knocked me off my workout schedule for 2 months while I recovered. Despite my best efforts, I was never able to reestablish my routine. I now weigh less than when I graduated high school at nearly 40. And, to boot, I suffer from arthritis now and exercising is near impossible for me now without great risk of being laid up in bed with a severe pinched nerve.