Additional Kcal Burned by Replacing Sitting for One Hour with Walking for One Hour

An average adult burns about .45 Calories (kcal) per pound (lb) of body weight per hour (kcal/lb/hr) for very sedentary activities, e.g., sitting quietly and reading or watching TV. Walking burns considerable more kcal. For example, walking at a moderate pace (3 mph) burns 1.5 kcal/lb/hr. Therefore, if one replaces sitting quietly for one hour with walking at a moderate pace for one hour, one will burn an extra 1.05 kcal/lb/hr (1.5 kcal/lb/hr - .45 kcal/lb/hr).

Example Calculation for 150 lb person who replaces sitting with walking for 1 hr

1.05 kcal/lb/hr x 150 lb x 1 hr = 158 kcal

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Additional Kcal Burned by Replacing Sitting with Walking One Mile

It is often stated that walking a mile burns about 100 kcal. For most folks, this value overestimates the total kcal burned while walking. Even more so, this figure overestimates the additional kcal burned from walking. The "additional kcal" are those EXTRA kcal that are burned on top of what you would burn anyway just for resting--sitting quietly.

Example for total kcal burned: The rate for total kcal expenditure of walking at a moderate or brisk pace is ".5 kcal/lb/mi." Therefore, to walk one mile, a 150 lb person would burn a total of 75 kcal (.5 kcal/lb x 150 lb x 1 mi).

Example for additional kcal burned: The rate for additional kcal of walking at a moderate or brisk pace is ".35 kcal/lb/mi." Therefore, to walk one mile, a 150 lb person would burn an additional 54 kcal (.35 kcal/lb x 150 lb): 53 kcal more than s/he would burn resting for the same length of time. See below for the derivation of ".35 kcal/lb/mi."

Example for Two Miles. If the individual in the example immediately above increased her distance to 2 miles per day, s/he would burn an additional 106 kcal (53 kcals/mi x 2 mi).

How Was ".35 kcal/lb/mi" Derived?

When an individual walks at 3 mph, in 1 hour she will walk 3 miles. Therefore, in 20 minutes (1/3 hour or .33 hour) she will walk 1 mile.

The rate at which she burns additional kcal per hour is 1.05 kcal/lb/hr. Therefore, per 1/3 hour or per mile, the rate at which she burns kcal is only 1/3 as large: 1.05 kcal/lb/hr x .33 hr/mi = .35 kcal/lb/mi.