Ultra short-term heart rate recovery after maximal exercise in continuous versus intermittent endurance athletes

This study tested the hypothesis that athletes participating in intermittent sports would exhibit a faster heart rate recovery (HRR) during the initial phase (<30 s) following maximal exercise than athletes participating in continuous endurance sports. Forty-six male athletes were allocated into continuous (CNT, n = 24) or intermittent groups (INT, n = 22), matched for age and aerobic fitness. Athletes performed maximal exercise on a treadmill using the ramp protocol. Immediately upon exercise cessation, subjects were placed supine with continuous measurement of HR during the first minute of recovery. Data were analyzed in 10-s intervals and compared between the groups. Repeated measures ANOVA showed a group × time interaction effects (p ≤ 0.01) for HRR expressed in both beats min⁻¹ and in percentage of peak post-exercise HR (% HR_peak). The INT group had lower HR than CNT group at 10 s (189 vs. 192 beats min⁻¹, p = 0.04; and 96.3 vs. 97.9% HR_peak, p = 0.009) and 20 s (184 vs. 188 beats min⁻¹, p = 0.049; and 93.6 vs. 95.7% HR_peak, p = 0.021) intervals of recovery. The results suggest that athletes engaged in intermittent sports are likely to have faster HRR during the first 20 s after maximal exercise than their counterparts trained for continuous performance.