'Maximum' heart rate is an urban myth. It's a calculated expected maximum which many people can go above. It's like the speed of a car, rather than the RPM with

'Maximum' heart rate is an urban myth. It's a calculated expected maximum which many people can go above. It's like the speed of a car, rather than the RPM with its redline failure meltdown. Various things affect HR, for example race-day HR is usually 10BPM higher than normal. For this reason HR is more of a helpful secondary metric for an sport with 'real' metrics like speed/distance/weight. Did the fitbit put her at risk? Only if she ignored all other signs of overexertion or danger, like chest pains, dizzyness, pounding heart beats, etc.