I don't know... If you're actually exercising an hour and a half each day, every day, you're going to be incurring some pretty regular exercise related injuries and degeneration. Your heart might like all that running, but your knees are going to make you regret it.
> If you're actually exercising an hour and a half each day, every day, you're going to be incurring some pretty regular exercise related injuries and degeneration
The human body evolved for that, and much more, you're not training 90 min per day at athlete level performance, you'll be fine... Of course if you run 10 hours per week with bad technique you're going to fuck your shit up, but you can easily alternate 60 min of gym/cardio every day with very little chance of injuries + an evening 30min "brisk" walk or 30 min of bicycle commute.
It's your body, do as you want, but chances are you exercise (way) too little, not too much
Nowadays exercising might mean walk at decent pace. People acts like they are asking you to run 90 minutes daily at marathon record pace, when they are actually saying to walk briskly for trips less than a mile, or take the stairs instead of the elevator.
Only a few people take benefit from running heavier than 5 km (3 miles) in 30 minutes every other day. The rest of you exercise should come from anything that is not driving or browsing the web.
Running is not the only form of exercise. There are plenty of low impact forms of exercise out there that can get you into any zone of cardio you want.