Just got myself a treadmill, a decent one that was used in my local gym so of course has all the "fancy features". However, I am majorly unfit these days, I can walk for miles and miles but anything other than that I'm hopeless. I should be able to build up fast enough, I was very sporty when I was younger and played many sports but that stamina seems to have gone.

My question is, what is the best way to start on the treadmill? Slower speeds and build it up or a huge burst and do as much as I can. I don't know what will be better in the long run for weight loss and fitness.