Usually the calorymetric measurement over pulse is working quite well inside absolutely acceptable limits.
But under some condition this is getting realyy bad - What I observed:
(ME... that is a quite heavy, but well trained person: Weight abt. 110 Kilogram, running under 6 min/km over more than 10 km and I am able tu push 130kg on benchpress... I doing crossover-sports for about 25 Years. Getting a little fat last time... ;-) )
(1) Capturing only every second (!) beat of the heart...
... after increasing heartbeat quite quick. Cycling quite chilled, 115 BPM over some dozen km - No problem: Kcal and BPM counting is good. But if there will be an extreme spring letting the pulse raise from 115 to ober 180 per minute in less than a minute the GARMIN INSTINCT TACT seems to be suspendes: Until reacing BPM under 100 again the device counts only every second (!) beat. So manual pulse measurement (counting as good as possible at this high rates...) compared to the display will show quite exact a division by 2 - Measurement will get incorrect due to this issue.
(2) "Underperformance" Sports...
If I am on a trekking tour, wearing a heavy Backpack beneath my own weight in the mountains and GPS will measure correctly: 16km and the kcal will say: You´ve burned 600 kcal... Sorry: No way! At least this should be abt. 1500kcal or more due to severel hundreds of meter climbing and downhill and feeling extremely exhausted. (Quite easy: Over the years I´ve got a feeling for this: Eating meals with several thousands kcal on those trekking tours will effect loss of weight - So the "output" must be over "input"...)
Trekking and walking: If the pulse stay under (quite exact) 100 BPM, the measurement beacomes quite unplausible. Is this an issue of the algorithm itself - Or the implementation of the algorithm (maybe the principle of measurement?) inside the Instinct Tact?
To simplify - Again the two issues I have examined:
First: If there is very quick raise of BPM, the Instinct Tact starts counting only every 2nd beat which will lead into wrong result of kcal and wrong pulse logging, too.
Second: If there are low-performance sports which will have a long duration of hours under a pulse of (quite exact) 100 - The calorimetrical results leaving acceptable tolerance. (Counting will be min. factor of 2 under plausible results.)
Maybe somebody else detected this two issues. Mostly the watch works well... but in some cases the measurements seems to be inacceptable wrong. This is not a really big thing, but annoying anyway.
