Question: how long do you have to workout to burn 1000 calories?
Answer: I am 6′ and 200 lbs, and when I walk at 4 mph and a 6% incline, I burn about 1,000 calories an hour. So one way to reach your goal is to do this for 5 hours (adjusting for your calorie burn based on your own research). Note that this activity is the go-to exercise for contestants on The Biggest Loser.