About a month ago I wanted to change up my routine - I normally do the elliptical for my workout. I have tried running before but never stuck with it. So I started running on the treadmill - or a combo of walkling running. I get 3 days in the gym and try to make the most of them so I do both cardio and strength training. I start with 10-15 minutes on the elliptical, then I do strenth training (upper body - if I'm doing treadmill) for 30-45 minutes. Then I get on the treadmill, I walk for a minute, then run for a minute and alternate at a 5% incline and walking pace of 4mph and running at 5mph. The first 10-15 minutes are killer - I feel like I can't do this - but if I push through by minutes 20-30 - its all very natural - why is it that the second half seems so much easier - even though I'm starting to tire by this point?