Heart rate overshoot in running events

The phenomenon of heart rate overshoot has been examined in 6 high-school athletes aged 15-16 years and in 8 university athletes aged 19-20 years. The incidence was 100% over distances of 50, 100 and 200 metres, and only one subject failed to show an overshoot following a 400 metre run. However, the overshoot was relatively larger and more long-lived following the shorter runs. While an accumulation of anaerobic metabolites seems the most likely explanation of the phenomenon over the longer distances, in the 50 metre event the Valsalva manoeuvre may also make some contribution.