Reliability of recovery heart rate variability measurements as part of the Lamberts Submaximal Cycle Test and the relationship with training status in trained to elite cyclists

To determine if post-exercise heart rate variability, in the form of logged transformed root mean square of successive differences of the R–R intervals (LnRMSSD) can be measured reliably during the recovery from a submaximal cycle test and what the relationship of LnRMSSD is with training status of the cyclists.

Fourteen male cyclists participated in the reliability part for the study, which included performing six Lamberts Submaximal Cycle Test (LSCT), during which recovery LnRMSSD was measured over 30 s (LnRMSSD_{30 s}), 60 s LnRMSSD_{60 s})and 90 s LnRMSSD_{90 s}). In addition, fifty male and twenty female cyclists completed a peak power output (PPO) test (including VO_2peak) and 40 km time trial (40 km TT) before which they performed the LSCT as a standardized warm-up. Relationships between the LnRMSSD and PPO, VO_2peak and 40 km TT time were studied.

Due to the design of the LSCT, submaximal heart and breathing rate were similar at the end of stage 3 of the LSCT, as well as during the recovery periods. The highest reliability was found in LnRMSSD_{60 s} (ICC: 0.97) with a typical error of the measurement (TEM: 5.8%). In line with this the strongest correlations were found between LnRMSSD_{60 s} and PPO (r = 0.93[male]; 0.85[female]), VO_2peak (r = 0.71[male]; 0.63[female];) and 40 km TT (r = – 0.83[male]; – 0.63[female]).

LnRMSSD_{60 s} can be measured reliably after the LSCT and can predict PPO, VO_2peak and 40 km TT performance well in trained-to-elite cyclists. These findings suggest that recovery LnRMSSD can potentially play an important role in monitoring and fine-tuning training prescriptions in trained-to-elite cyclists.