Exercise dose can be determined using kilocalories (kcal). Daily and weekly exercise goals can conveniently and easily be set in terms of kcals. Because the heart rate monitor tracks both the energy/kcal expenditure in one exercise session and the accumulated kilocalories of several sessions, during e.g. a week or a month, it helps in achieving the energy expenditure goals.
Facts affecting exercise energy expenditure
The amount of energy expended during exercise depends on exercise intensity and duration. The higher the intensity and the longer the duration, the greater the energy expenditure. Energy expenditure is also dependent on body weight, so that a heavier person consumes more energy than a lighter one when performing the same exercise because the mass that the person needs to move is greater. For example, persons weighing 60 kg and 100 kg expend 5 kcal and 8 kcal per minute in brisk walking, respectively. Also, the larger the muscle mass used in the exercise the greater the energy expended. Thus, very high energy expenditures can be reached in e.g. cross-country skiing and rowing. Types of exercise where the person must support his/her body weight typically expend more calories than types where the exercise equipment supports the weight.
Physical activity for weight loss purpose
For weight loss purposes the recommended energy expenditure can be set to 300 kcal/ session. Conducted on most days of the week this will result 2000 kcal/week on a 70 kg person, approximately the kilocalorie content of a 1 kg (or 2 pounds) fat (7000 kcal) in a month.
Comparison between the distribution of energy sources in jogging and walking
Additional reading: Kukkonen-Harjula K, Laukkanen R. Precision Weight Management. Polar Electro Oy. Third Edition in English, 1998.