How to lose 40 pounds using my treadmill?

45-60min/day and... With regular, medium-high intensity 5-6x/wk workout and a healthy/balanced diet along with setting a realistic, steady wt loss 3-4lbs/month, you can accomplish this. Don't do crash diet because u will like regain it and some more later. Drink plenty of fluid, especially water, minimize junk foods/sweet drinks and you will succeed. Remember: staying healthy is a life-time committment. Good luck.