longer than 35 minutes? some? days I will go for 35 min at 7.5 mph, and other days I will run for an HOUR at 7.5 mph. After I am pretty much drenched in sweat. But on average I run for 40 minutes at 7.5 mph. Afterwards I am drenched in sweat. Now is this too much? and WHY doesn't ANYONE ever run...