Calories Burned Walking with a Manual Wheelchair: A Detailed Estimate

Question
I am a 5'6", 170 lb. 48 year old female. How many calories did I burn walking 3 miles pushing my son in a manual wheelchair (total weight 340lbs.) It took me 45 minutes

Answer
It may sound odd, but it is quite difficult to say how many calories you burned. You certainly must have worked hard to average 15 minute miles.

By yourself, you probably burn somewhat more than 100 calories per mile. The extra weight of the wheelchair would add to the calorie burn, but the fact that it was on wheels reduced the effort. In addition, if you leaned on the wheelchair while pushing, that took some weight off of your feet, which could also reduce the calories required.

My best estimate is between 400 and 500 calories for the three miles, but that is just an educated guess.