Kcal Expenditure from Walking

References
Background
Total Kcal Burned
Additional Kcal Burned
Taking the Stairs
Weight Control Benefit
Walking Routes
Using Pedometers

References for Calorie (kcal) Values

The values shown below for the approximate Calorie (kcal) expenditure of walking are based on the MET values provided by Ainsworth in The Compendium of Physical Activities Tracking Guide. Calculations that include ascending and descending flights of stairs also utilize the approximate kcal values provided by Taylor in Guthrie and Picciano. Calculations for "Additional Calories Burned" and "Weight Control Benefit" are informed by Guthrie and Picciano.

Background on METs

What is a MET? One MET is the rate at which adults burn kcal at rest: This is approximately 1 kcal per kilogram (kg) of body weight per hour (expressed as 1 kcal/kg/hr). MET stands for metabolic equivalent and is defined as "the ratio of the work metabolic rate to the resting metabolic rate" (Ainsworth).

MET Value of 1. In The Compendium of Physical Activities Tracking Guide, an activity with a MET value of "1" (e.g., sitting quietly and reading or watching TV) would have an energy expenditure of 1 kcal/kg/hr. Therefore, sitting quietly does not require any more kcal than one would burn just to rest. Sitting quietly and other "activities" that have MET values close to 1 are considered "sedentary" activities.

MET Values > 1. The Compendium lists a MET value of 3.3 for walking at a moderate pace on level ground. Accordingly, walking at a moderate pace on level ground would have an energy expenditure of 3.3 kcal/kg/hr (3.3 times that of the resting metabolic rate, which is 1 kcal/kg/hr).

Compendium of MET Values. For information on using the MET values of the 600+ different activities listed in the Compendium, see "Understanding and Using the MET Values." The information below focuses only on using METs walking.

Kilograms vs Pounds. In the United States, pounds (lb), not kg, is the unit of body weight to which individuals are accustomed. Therefore, it is necessary to convert "kcal/kg/hr" to "kcal/lb/hr" using the conversion 1 kg = 2.2 lb. Simply divide the MET value listed for any activity in the Compendium by "2.2" in order to make this conversion. All MET values listed subsequently in this document have been adjusted to show kcal/lb/hr. Below are example conversions for two activities listed in the Compendium of Physical Activities: Sitting quietly (1 MET) and walking at a moderate pace (3.3 MET).

Example to Convert 1 MET

1 kcal/kg/hr = .45 kcal/lb/hr (Therefore, 1 MET = .45 kcal/lb/hr)
2.2 lb/kg

Example to Convert 3.3 MET

3.3 kcal/kg/hr = 1.5 kcal/lb/hr (Therefore, 3.3 MET = 1.5 kcal/lb/hr)
2.2 lb/kg

These MET values then can be used to determine the approximate number of kcal burned by an individual of a given body weight who engages in the activity for a specified length of time (Note: The answers are rounded to nearest whole kcal):

Example Calculations for Sitting Quietly for One Hour

150 lb person: .45 kcal/lb/hr x 150 lb x 1 hr = 68 kcal
200 lb person: .45 kcal/lb/hr x 200 lb x 1 hr = 90 kcal

Example Calculations for Walking Moderately (3 mph) for One Hour

150 lb person. 1.5 kcal/lb/hr x 150 lb x 1 hr = 225 kcal
200 lb person. 1.5 kcal/lb/hr x 200 lb x 1 hr = 300 kcal

Determining the Kcal Burned by Walking

The kcal expenditure from walking can be calculated in two ways:

(1) total kcal burned while walking;
(2) additional or extra kcal burned from walking.

The value from method 1--total kcal burned--includes the kcal an individual would burn anyway just to maintain life at rest (e.g.,sitting quietly). The MET values given in the Compendium for any activity INCLUDE the kcal burned just to maintain life at rest. In other words, the MET values in the Compendium will yield the total kcal expended while doing an activity (See example calculations above: A 150 lb person who walks moderately for 1 hour will burn a total of approximately 225 kcal).

The value from method 2--extra kcal burned--excludes (subtracts) the kcal that an individual would burn anyway just to maintain life at rest (sedentary activity). When an individual decides to increase physical activity level, the individual replaces a sedentary activity (e.g., sitting quietly) with a more vigorous activity (e.g., walking at 3 mph). Therefore, method 2 more accurately quantifies the "weight control benefit" of walking by removing those kcal that an individual will burn anyway--the kcal s/he must burn just to maintain life at rest.

Examine the calculations that follow to see the differences between total kcal burned and extra kcal burned by walking

Total Kcal Burned While Walking

Per Unit of Time. To calculate the total kcal burned while walking for a specific amount of time (hr) at various speeds, use these values:

Per Mile. To determine the total kcal expended from walking a specific distance (miles--mi) at various speeds, use these values:

Example Calculations for Walking One Mile at 3 mph

150 lb person: .5 kcal/lb/mi x 150 lb x 1 mi = 75 kcal
200 lb person. .5 kcal/lb/mi x 200 lb x 1 mi = 100 kcal

Additional (Extra) Kcal Burned From Walking

Per Unit of Time. To calculate the additional kcal burned from walking for a specific amount of time (hr) at various speeds, use these values:

(Note: The values above were derived by subtracting the MET value of "resting" from the MET value for walking at different speeds, e.g., for 3 mph: 1.5 kcal/lb/hr - .45 kcal/lb/hr = 1.05 kcal/lb/hr)

Example Calculations for Walking One Hour at 3 mph

150 lb person. 1.05 kcal/lb/hr x 150 lb x 1 hr = 158 kcal
200 lb person. 1.05 kcal/lb/hr x 200 lb x 1 hr = 210 kcal

Per Mile. To determine the additional kcal expended from walking a specific distance (miles--mi) at various speeds, use these values:

See More Background for further explanation and examples of "additional kcal burned."

Using the Stairs. One way that individuals can increase their kcal expenditure is by taking the stairs instead of the elevator (or just going up and down the stairs several times during the day for quick breaks). To calculate the additional kcal burned by taking the stairs, use these figures:

Weight Control Benefit of Additional Kcal Burned

Medical Clearance. Before increasing physical activity level, adults should complete the Physical Activity Readiness Questionnaire/PAR-Q (pdf version) (html verison) and follow the recommendations based on their answers.

Preventing Gain or Losing Weight. The weight control benefit of walking on a regular basis (or a sustained increase in any physical activity) can be viewed in two ways:

(1) preventing weight gain--preventing the accumulation of body fat--specifically adipose tissue (example)

(2) losing weight--by burning fat that has been stored as adipose tissue (example)

In scenario 1 above, the goal is for walking to result in a situation where daily kcal intake equals daily kcal expenditure (equilibrium between expenditure and intake). Specifically, the goal is to prevent a "positive" energy balance. If an individual is in "equilibrium" on a regular basis (i.e., over an extended period of time), no weight is gained.

In scenario 2 above, the goal is for walking to result in a situation where daily kcal intake is less than daily kcal expenditure. This is called negative energy balance. If an individual sustains this negative energy balance over an extended period of time, weight loss occurs.

Adipose Tissue. Although not all weight gain (from positive energy balance) or weight loss (from negative energy balance) will be in the form of adipose tissue, the goal in weight control is to prevent the accumulation of or to lose adipose tissue. Accordingly, the approximate kcal value of adipose tissue (1 lb = 3500 kcal) is used in calculating the "weight control benefit" of physical activity.

Muscle Gain. Additionally, when sedentary individuals increase their physical activity level, they may gain muscle mass. When muscle mass is gained at the same time that adipose tissue is lost, the change in body weight on a scale will not show the actual amount of adipose tissue lost. A very positive aspect of gaining muscle is that muscle burns more kcal than fat in order to maintain itself.

Example Calculation for Preventing Weight Gain*

Mary weighs 150 lbs and has taken a new job that requires her to sit for long periods of time. She does not want to gain weight. She decides to start a walking program. Her walking program is as follows: Instead of sitting for her full 40 minute lunch break, she sits for 20 minutes and walks at 3 mph for the other 20 minutes. Additionally, she replaces 20 minutes of sitting watching TV in the evening with 20 minutes of walking (3 mph). Therefore, she replaces a total of 40 minutes (.67 hr) of sitting with 40 minutes (.67 hr) of walking. The number of additional kcal burned per day by Mary by replacing sitting for .67 hr with walking for .67 hr is:

1.05 kcal/lb/hr x150 lbs x .67 hr/day = 106 kcal/day

If Mary does this every day for one year (365 days), she will expend an additional 38,690 kcal (365 days x 106 kcal/day). This number of kcal is the equivalent of about 11 lbs of adipose tissue (38, 690 kcal / 3500 kcal per lb) over a full year.

Example Calculation to Lose Weight*

Sam weighs 200 lbs. His goal is to lose 20 lbs so his Body Mass Index (BMI) is no longer in the "overweight" range. He decides to start a walking program. His walking program is as follows: Instead of sitting for his full 40 minute lunch break, he sits for 20 minutes and walks at 3 mph for the other 20 minutes. Additionally, he replaces 20 minutes of sitting watching TV in the evening with 20 minutes of walking (3 mph). Therefore, he replaces a total of 40 minutes of sitting with 40 minutes of walking (.67 hr). The number of additional kcal burned per day by Sam by replacing sitting for 40 minutes with walking for 40 minutes is:

1.05 kcal/lb/hr x 200 lbs x .67 hr/day = 141 kcal/day

If Sam does this every day for one year (365 days), he will expend an additional 51,465 kcal (365 days x 141 kcal/day). This number of kcal is the equivalent of about 14.7 lbs of adipose tissue (51,465 kcal / 3500 kcal per lb) over a full year. Therefore, Sam will approach 3/4 of his weight reduction goal in one year.

NOTE: The above calculation of additional kcal burned in one year really is an overestimate because as Sam loses weight, he will burn fewer kcal walking the same distance. To be accurate, the calculation of additional kcal burned should be repeated after losing several pounds. For example, after 10 lbs of weight loss, Sam now weighs 190 lbs and burns 134 additional kcal (instead of 141 additional kcal) by replacing sitting for 40 minutes with walking for 40 minutes:

1.05 kcal/lb/hr x 190 lbs x .67 hr/day = 134 kcal/day

From a practical standpoint, Sam should increase slightly his time spent walking (or rate of walking or add some stair climbing) as he loses weight in order to keep burning the same number of additional kcal.

*The two examples above assume that the individual makes ONLY the lifestyle change described--the replacement of sitting with walking. In other words, the individual does not change his diet and he keeps his activity the same except for the replacement of sitting with walking. If diet or other activity changes are made, the kcal associated with those changes also would have to be factored in to the above calculations..

Walking Routes

Accuracy and Safety. Make sure that you have accurately measured/determined the distance of your route (1 mile = 5280 feet or 1609 meters) and insured that your route is safe (see also walkability checklist) for pedestrians to use.

Educating the Public. To prepare educational materials for educating the public on the approximate kcal burned from walking routes, it is best to use the kcal expenditure figures for walking at a moderate pace (3 mph). It also is good to show the kcal expenditures for a range of body weights (e.g., 10 lb increments from 120 to 260 lbs). For these different body weights, you can choose to calculate and provide the "total kcal burned" or the "additional kcal burned."

Additional Kcal Burned. If you choose to show "additional kcal burned," specify that you mean these are the additional kcal burned when the walking replaces sitting (see example). If your walking route includes going up and down an appreciable number of stairs, you want to make sure the additional kcal burned includes those kcal from using the stairs (see example). You also can show the kcal expenditure with and without including the stairs. Finally, you also can show the equivalent amount of body weight as adipose tissue if the additional walking was performed every day for a certain time period such as one year (see example).

Medical Clearance. When marketing or publishing written literature associated with your walking route, it is best to recommend that individuals seek and obtain medical clearance from their personal physician before increasing their physical activity level. The Physical Activity Readiness Questionnaire/PAR-Q (pdf version) (html verison) can be used to help individuals determine the necessity of obtaining medical clearance.

Steps to Calculate Kcal Expenditure. Employing the kcal values shown previously on this web page, here are a set of steps to follow to calculate and show the additional kcal burned from using a walking route and the adipose tissue equivalent of doing the route for a specified length of time.

Using Pedometers

Why use? Pedometers motivate people to walk and allow individuals to monitor their walking. All pedometers measure and report steps taken. To get an accurate reading, correct placement of the pedometer on the body is critical. Affix the pedometer to the waistband or belt directly up from the knee: See Pangrazi, Beighle & Sidman (p 23), who also provide quality assurance procedures to test pedometers for accuracy (p 31).

Stride Length. Pedometers that allow the user to set personal stride length also will calculate distance walked. For individuals with a stride length of 2.5 to 2.75 feet, 2000 steps is approximately one mile (1 mile = 5,280 feet). If the stride length entered into the pedometer is an overestimate of the individual's actual stride length (e.g., 2.75 feet is entered instead of 2.25 feet), the distance reported by the pedometer will be overestimated. This also will result in overestimating any kcal expenditure value provided by the pedometer (see below).

Kcal Expenditure. Pedometers that allow the user to set personal stride length and enter personal body weight also provide the kcal expenditure of walking. Unless stated otherwise, these are the approximate "total kcal" burned while walking. Pedometers will underestimate total kcal expenditure if the walking is done at a very brisk pace or includes considerable hill or stair climbing because the calculation is not adjusted for intensity or effort. For additional information on the limitations of pedometers to measure and report distance and kcal expenditure, see Tudor-Locke.

Instructions for Using. Here are instructions for determining and setting stride length as well as entering body weight in the Accusplit™ Eagle 170 pedometers. Here are similar instructions for the Accusplit Eagle 140s pedometers, which have a stop watch feature instead of a body weight/kcal expenditure feature. For other pedometers, refer to the instructions that accompanies the pedometer.

Pedometers for Learning Activities and a Walking Club Research Project. Pedometers are a great tool to teach students about experimental design and to stimulate inquiry-based learning. Here is a set of sample questions that can be answered through using pedometers. Additionally, here is a description of a research project that was carried out during the 2003-2004 school year to increase physical activity through walking clubs in schools. Here is a powerpoint that provides additional information on these endeavors.

References
Background
Total Kcal Burned
Additional Kcal Burned
Taking the Stairs
Weight Control Benefit
Walking Routes
Using Pedometers