85% this, 74% that, x amount of minutes, blah blah blah. unless you are a serious athlete there is only one thing you need to do to get benefit from exercise, and that is to actually do it. wanking on about correct heart rates and minutes needed to be run, all detracts from that. a 10 minute jog is far more useful to you healthwise than a 3 page thread about how long you should run for for.
Yep, just get out there and run. It's a typically cold, grey October morning here in Blighty and I'm heading out for a 5 mile run on the mean streets of Surrey.