Decreasing heart rate and feeling faint during a race

Yesterday my 16 year old daughter ran an XC race and half way through felt faint and lost all power, going from 1st down to 11th. Her HR graph shows that her HR was decreasing during the race. Has anyone ever come across this before?

It has happened to me during an ITT and suspect it’s fairly common (or at least common to inexperienced runners and cyclist) who go out of the start too hard. Throw in not being hydrated, heat, fatigue, fighting off a virus etc…and performance can go south real quick.


Rebound hypoglycemia maybe?

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And dehydration. Obvious answer: even though I’m sure some tr users here are actual doctors, go see yours to make sure everything is okay. Second answer, poor nutrition and hydration can have a profound impact on HR trends. Look at that data and see if it correlates to the HR data. Start the night before with dinner and hydration then work through the entire day to see what deficiencies there might be.

Yeah, i think you’re right: there must have been something poorly executed in the lead up, like nutrition or hydration…

She did have COVID about a month ago as well, so there is possibly some lingering problem there even though it barely touched her.

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