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# Energy Expenditure

Energy is measured in calories obtained from the body stores or the food we eat. The body requires energy for every physical activity, and the amount depends on the duration and type of activity. This article looks at the energy expenditure for walking and running.

### Walking

A linear relationship exists at walking speeds of 3 to 5 km/hr of oxygen consumption, but oxygen consumption rises at faster speeds, making walking less economical.

Body mass can be used to predict energy expenditure with reasonable accuracy at walking speeds of 2 to 4 mph (3.2 to 6.4 km/hr). McArdle (2000)[1] details the number of calories you will burn per minute for ranges of body mass (weight) and speed when you walk on a firm level surface.

If your body mass is 64 kg and you walk at a speed of 5.63 km/hr, then you will burn approximately 4.6 Calories/minute - if you walk for one hour, you will burn 60 × 4.6 = 276 Calories.

### Running

When running at identical speeds, a trained distance runner runs at a lower percentage of their aerobic capacity than an untrained athlete, even though the run's oxygen uptake will be similar for both athletes. The distinction between running and jogging depends on the individual's fitness level. Independent of fitness, it becomes far more economical from an energy viewpoint to change from walking to running when your speed exceeds 8km/hr (5mph). Above 8km/hr, a walker's oxygen intake exceeds a runner's oxygen intake. At 10km/hr, the walker's oxygen (O2) uptake is 40 ml/kg/min compared to 35 ml/kg/min for the runner See McArdle (2000) [1] .

Body mass can be used to predict energy expenditure with reasonable accuracy when running on a firm level surface (road, track or grass). The number of calories required to run 1 km equals your weight in kg (a runner of 78 kg will burn 78 Calories/km).

One litre of oxygen equals five calories, so our 78kg runner utilises 15.6 litres of oxygen per kilometre.

McArdle (2000)[1] details the number of calories you will burn per minute for ranges of body mass (weight) and speed when you run on a firm level surface

### How Exercises Compare

The following table, adapted from McArdle (2000)[1], contains the approximate caloric expenditure in 30 minutes of exercise for a person weighing 68kg for various exercises and the intensity of work. Add 10% for every 7kg over 68kg and deduct 10% for every 7kg under 68kg

 Exercise Intensity Calories/½ hour Aerobics Light 120 Moderate 200 Vigorous 300 Walking 4 km/hr 105 7 km/hr 200 10 km/hr 370 Running 9 km/hr 320 10 km/hr 350 12 km/hr 430 16 km/hr 550 Cycling 9 km/hr 120 16 km/hr 220 21 km/hr 320 Swimming 25 metres/min 165 40 metres/min 240 50 metres/min 345 Rowing Light 200 Vigorous 420

### Calorie Calculator

Enter the exercise & intensity, duration, and weight and then select the "Calculate" button to analyse the number of calories expended.

 Exercise Aerobics - light Aerobics - Moderate Aerobics - Vigorous Cycling - 9 km/hr Cycling - 16 km/hr Cycling - 21 km/hr Rowing - light Rowing - Moderate Rowing - Vigorous Running - 9 km/hr Running - 10 km/hr Running - 12 km/hr Running - 16 km/hr Swimming - 25 m/min Swimming - 40 m/min Swimming - 50 m/min Walking - 4 km/hr Walking - 7 km/hr Walking - 10 km/hr Duration minutes Weight kg Energy expenditure Calories

### References

1. McARDLE, W.D. et al. (2000) Energy expenditure at rest and during physical activity. In: McArdle, W.D. et al., 2nd ed. Essentials of Exercise Physiology, USA: Lippincott Williams and Wilkins