I do 30 minutes on the treadmill at 3.2 most every day of the week, except leg day, and maybe the day after legs depending on how I feel, lol. I just feel so much better, especially now that I have 'aged,' lol. I don't have huge legs, so I have to be careful to not have it negatively effect me in that way. That said, a measly 30-min of just brisk walking has never effected me bad. I remember Duchaine mentioning the same thing. I usually do either walking on the treadmill or get on the stationary bike. I still try to do it fasted in the morning if possible and then train later in the day. If not, i'll hit 20-30 min post-training.