2023-07-02 05:48:23
If you train continuously with a heart rate monitor, you’ve probably noticed that heat has a direct impact on heart rate. Clearly, there is a discrepancy between the effort felt and the figure indicated on the “cardio”. Very destabilizing at first sight, this phenomenon can however be explained very simply.
To explain this heart rate, which could be described as “artificially high”, we use the term cardiac drift.
Clearly the heart rate is higher for all intensities of effort. In other words if, for example, at 200W you are usually at 150bpm, you will be at 155 or 160bpm in high heat. Another example, at constant speed without wind or slope and with ease of breathing, you will be 5 to 10bpm above the “felt” and usual value. This cardiac drift constitutes a limit to performance because it reduces the room for manoeuvre, the “cardiac reserve”.
Another observation: after an intensive effort (hill for example), your heart rate will have more difficulty in coming down. We can also cite the difficulty in multiplying intensive and maximum efforts, or the feeling of “soft legs”, of lack of strength.
We can also see that at the end of the course, with the accumulated fatigue, the heart rate tends to remain high for a moderate effort.
If you have to work in a “target” intensity zone (“threshold” session for example), try to keep your heart rate within the lower limit of this effort zone. In fact, the heat will cause a more marked cardiac drift than usual and, at constant power (watts), your heart rate will increase significantly over the minutes of effort.
We strongly advise you not to fix your attention too much on the heart rate in case of high heat. Indeed, you risk not working in the right intensities. This is an additional reason to use a power sensor, which is completely independent of this “temperature” parameter.
Finally, note that this cardiac drift (higher and more unstable heart rate during exercise) is accentuated by dehydration which also causes an “artificial” increase in heart rate.
Training in high heat therefore requires good self-knowledge, and being able to trust the sensations without making mistakes.
Also consider limiting the intensity, or even canceling an outing when the temperatures are scorching (above 35°) so as not to put your health at risk. Sunstroke, for example, causes a state of marked fatigue for several days.
Benoit VALQUE
1688277497
#effect #heat #heart #rate #performance