Many heart rate monitors and bike computers has a feature to measure the energy cost of the exercise. But can we believe these numbers? I have always been sceptical to these calculations since they are based on very few variables (percentage of maximum heart rate and total time). I have always said to my riders that they can use these numbers for fun, but don’t count on them when they cook dinner. There is probably huge variability in the quality of calorie metres, some gives a rough estimate and some doesn’t.

Can heart rate monitors be used to calculate energy expenditure?

Yesterday I found a study published in Medical Science of Sports and Exercise that tried to figure out how accurate the energy expenditure calculator of the Polar s-410 heart rate monitor was. They used three different calculations of the energy expenditure: 1) Polar s-410 using predicted values of VO2 max and maximum heart rate. 2) Polar s-410 using actual values of VO2 max and maximum heart rate. 3) Indirect calorimetry (You might have heard about this one in school”¦)

The results showed that the Polar s-410 did a quite good job for the men with no significant differences between the three calculation methods. The women’s numbers were overestimated when using predicted values of VO2 max and maximum heart rate. The estimation was better when they used the actual values but still overestimated with 12%.

Read the full article about Polar S-410