There are plentiful theories dealing with calories burning during physical activity. The bad news is that a significant number of the data speaking of energy expenditure turns out to be decidedy overrated. In practice the largest overvaluation is spread by those who stubbornly troddle on a treadmill, stationary cross trainers and bikes in fitness clubs. So let's shed some light on the subject and through the prism of a practical example illustrate how long we need to run to burn 500 kcal.
How much is 500 kcal?
Before we get down to a specific consideration and calculation of energy expenditure during standard physical activity, we should first explain what the actual 500 kcal mean. Well, there is no doubt that 500 kcal is not a slight dose of energy. This is a significant amount for our daily calorie requirements, which, although variable, are usually housed within a certain frames. Our ability to burn this amount of energy depends on the individual anthropometric parameters (such as age, height, weight, gender) and physical activity. It may be said that a healthy, adult women who are not professional sportspersons need from 1700 to 2600 kcal a day, while men usually requie about 20-40% more. Of course, we are talking about average activity people who train on a normal basis (naturally, physical needs of high-performance athletes are substantially larger).
On the basis of the above information, it can be said that for average "mortals" who do a recreational training 2-4 times a week 500 kcal is quite a bit. This is the energy value that can cover a pretty decent meal. For example, such amount of calories can be supplied by eating 100 g of rice, 150 g of chicken breast and 200 g of non-farinaceous vegetables. To compare, you can consume the same amount of energy having just one piece of cheesecake followed by a cup of coffee with sugar and milk. What's more, you can easily acquire 500 kcal by enjoying "dietary" 1 litre of fruit juice 100%. So as you can see it is very easy to add some extra 500 kcal not included in your diet. It's a completely different story to burn this amount, though.
How much time do I need to run to burn 500 kcal?
As a nutritionist, during professional consultations I often ask my customers how to burn, in their opinion, a given amount of energy adopted with food. And I am notoriously offered far too optimistic answers. Well, practice shows that we are in the habit of overvaluing our energy expenditure associated with physical activity. This fact has been confirmed not only by my observations but also by some scientific research. This phenomenon leads to a situation in which we train less than we ought to to burn the additional calories. Needless to say, the result of such an occurence is a lack of desired effects and a frustrating conviction that "the training does not work".
It is good to know that you burn approximately 5 to 7 kcal per one minute of a low or moderate intensity aerobic training. Experimental data indicate that during 30 minutes of constant run training at the level of 50% VO2max (maximal oxygen consumption), your average caloric expenditure is only 200-250 kcal! So in order to burn the already mentined 500 kcal, you would have to cover an hour of continuous run. Stationary fitness equipment available in fitness clubs overstate your training result sometimes by 100%!
To sum up
To burn the amount of 500 kcal, which equals for instance a McDonald's sandwich, you must run for at least an hour. It is worth remembering especially before you decide to diversify your diet with such an addition of energy.