Plews DJ, Laursen PB and Buchheit M. Day-to-day heart rate variability (HRV) recordings in world champion rowers: appreciating unique athlete characteristics. IJSPP 2016, In press.
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Purpose: Heart rate variability (HRV) is a popular tool for monitoring autonomic nervous system status and training adaptation in athletes. It is believed that increases in HRV indicate effective training adaptation, but these are not always apparent in elite athletes. Methods: Resting HRV was recorded in 4 elite rowers (Rower A, B, C and D) over the 7-week period prior to 2015 World Rowing Championship success. The natural logarithm of the square root of the mean sum of the squared differences between R–R intervals (Ln rMSSD), Ln rMSSD:R-R ratio trends, and the Ln rMSSD to R-R interval relationship were assessed for each champion-winning rower. Results: The time course of change in Ln rMSSD was athlete-dependant, with stagnation and decreases apparent. However, there were consistent substantial reductions in the Ln rMSSD:R-R ratio, Rower A: baseline towards week 5 (-2.35 ±1.94); Rower B baseline to week’s 4 and 5 (-0.41 ±0.48; -0.64 ±0.65 respectively); Rower C baseline to week 4 (-0.58 ±0.66); Rower D baseline to week’s 4, 5 and 6 (-1.15 ±0.91; -0.81 ±0.74; -1.43 ±0.69 respectively). Conclusion: Reductions in Ln rMSSD concurrent with reductions in the Ln rMSSD:R-R ratio are indicative of parasympathetic saturation. As such, 3 of 4 rowers displayed substantial increases in parasympathetic activity despite having decreases in Ln rMSSD. These results confirm that a combination of indices should be used accordingly to monitor cardiac autonomic activity.
Keywords: cardiac parasympathetic function, monitoring, elites
Le Meur Y, Buchhei M, Aubry A, Coutts AJ and Hausswirth Ch. Assessing overreaching with HRR: what is the minimal exercise intensity required? IJSPP 2016, In press.
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Figure 1 – Changes in heart rate recovery (HRR) at all running intensities during the maximal incremental running test during the overload period. f-OR: functional overreaching.
Purpose: Faster heart rate recovery (HRR) following high-to-maximal exercise (i.e. ≥90% HRmax) has been reported in athletes suspected of functional overreaching (f-OR). This study investigated whether this response would also occur at lower exercise intensity. Methods and Results: Heart rate recovery and rate of perceived exertion (RPE) responses were compared during an incremental intermittent running protocol to exhaustion in twenty experienced male triathletes (8 control and 13 overload subjects led to f-OR) before (Pre), immediately after an overload training period (Mid) and following a 1-week taper (Post). Both groups demonstrated an increase in HRR values at Mid, but this change was very likely to almost certainly larger in the f-OR group at all running intensities (large to very large differences, e.g. +16 ±7 bpm vs. +3 ±5 bpm, in the f-OR and control groups at 11 km×h-1, respectively). The highest between-group differences in changes in HRR were reported at 11 km×h-1 (13 ±4 bpm) and 12 km×h-1 (10 ±6 bpm). A concomitant increase in RPE values at all intensities was reported only in the f-OR group (large-to-extremely large differences, +2.1 ±1.5 to +0.7 ±1.5 AU). Conclusion: These findings confirm that faster HRR does not systematically predict better physical performance. However, when interpreted in the context of the athletes’ fatigue state and training phase, HRR following submaximal exercise may be more discriminant than HRR measures taken following maximal exercise for monitoring f-OR. These findings may be applied in practice by regularly assessing HRR following submaximal exercise (i.e., during warm-up) for monitoring endurance athletes responses to training.
Keywords: fatigue, overtraining, heart rate, cardiac response, endurance training