4 articles
Across 5311 athletes, maximum heart rate on the bike came out just 2 beats lower than in running. But you still can't carry threshold zones from one sport into the other β and here's why the group average is useless.
A 2026 systematic review: handheld lactate meters correlate with the laboratory reference at r = 0.95β0.99. And yet the spread of a single measurement at 3 mmol/L is Β±0.4 mmol/L. Here is why that is not a contradiction.
The useful signal in an optical heart rate sensor is just 1β2% of the reflected light, and every foot strike attacks it from three directions at once. Here is why your heart rate βsticksβ at 180 during intervals β and why no firmware update will fix it.
Familiar situation: you're running your usual route, same pace, but heart rate is 15 beats higher. Legs feel heavy, breathing harder. Overtrained? Getting sick? Or is it simpler β and scarier?