How much exercise should you do to reduce weight
Diet, combined with exercise, reduces weight. A lot has been said about the caloric restriction in diet needed for a person to make this happen. In the same way, you can customise the calories to be expended by physical activity. You can plan your exercise regimen by deciding how many calories should be burnt and then calculating the calories expended through different kinds of exercise.
For example, say you want to reduce one kilo every week. You can reduce your food intake by 700 kcal and exercise to burn another 300 kcal. This way you should reduce one kilo / week theoretically.
The good news for the overweight is that the more obese you are the more calories you will burn with exercise. This is because the body needs to exert more to move a heavier body around and perform the physical activity. Thus if you are a hundred kilos, then walking for 60 minutes will let you expend 480 kcal while someone who is 70 kg will burn only 335 kcal. This is the reason why someone who is not too overweight finds it difficult to reduce weight fast.
The other side of this rule is that as you reduce weight you may find your weight loss also slows down with the same amount of exercise. This means if you have reduced your weight from 100kg to 80 kg, then your usual one hour walk will not burn 480 kcal but 380 kcal.
You can calculate your own energy expenditure with whatever exercise you are choosing on your exercise plan. And as you reduce weight, you may increase the exercise time so as to lose more weight, or you may choose to slow down your weight loss process by continuing the present activity level.
Katch and McArdle in their book Exercise Physiology, describe the following activities and their energy expenditures in kcal/minute/kilo body weight:
Running at a speed of 12minutes/mile 0.12
Walking at 20 min / mile 0.08
Cycling < 10mph 0.12
Cycling stationery 0.09 to 0.22 depending on the speed
Calisthenics like push ups, etc 0.08
Stretching / yoga 0.06
Aerobics low impact 0.09
Swimming light 0.10
Washing car 0.07
Cooking food 0.04
The activity should be done continuously to get the desired calorie loss. You may combine activities if you get bored with one kind of activity. For example to use up 300 kcal /day you can choose combinations of activities as follows (calculated for a 70 kg man/woman)
· 35 minutes of walking and 25 minutes of stretching or yoga
· 30 minutes of aerobics and 15 minutes of stationary cycling
· 55 minutes of walking
· 15 minutes of running and 35 minutes walking
· 10 minutes of push ups, 10 minutes of cycling stationary and 32 minutes of walking
Looking at this exercise profile it becomes clear that one needs to exercise 45 min to one hour daily. You can split the activities into 25-minute sessions done twice a day if you do not have time at a stretch to complete the energy expenditure plan.
Whatever it is, you must have a calculated physical activity so that you are able to understand how certain activities make you reduce weight while other, less strenuous ones, do not.
Parvathy R Krishnan
The author is a trained Nutrition & Dietetics expert with over 20 years’ of experience in hospitals like Vijaya Hospital in Chennai and the Armed Forces Hospital and New Mowasat Hospitals in Kuwait. She is presently a member of the Research Society for the Study of Diabetes in India. Parvathy blogs at http://premadiet.blogspot.in/
More by this author:
Image: Georgia National Guard