Identification and comparison of heart-rate dynamics during cycle ergometer and treadmill exercise

Fig 1. Test protocol for the cycle ergometer (work rate/(W)) and treadmill (speed/(m/s)).

Fig 2. CE: Original data records and parameter estimation results for a single participant (participant No. 14) on the cycle ergometer. The upper panel shows the measured and model-simulated heart rate. The lower panel shows the manipulated variable (CE—work rate). Input-output data were detrended and mean levels subtracted prior to estimation. τ = 57.3 s, k = 0.51 bpm/W, RMSE = 2.3 bpm.

Fig 3. TM: Original data records and parameter estimation results for a single participant (participant No. 14) on the treadmill. The upper panel shows the measured and model-simulated heart rate. The lower panel shows the manipulated variable (TM—speed). Input-output data were detrended and mean levels subtracted prior to estimation. τ = 49.7 s, k = 29.4 bpm/(m/s), RMSE = 2.4 bpm.

Fig 4. Primary outcome: Data samples for time constant τ for all 25 participants for the cycle ergometer CE and treadmill TM (see also Table 1). The green lines link the sample pairs from each participant. The red horizontal bars depict mean values (given numerically in Table 1). D = CE—TM is the difference between the paired samples. MD is the mean difference (red horizontal bar), with its 95% confidence interval (CI) in blue. The value 0 is within the 95% CI, indicating no significant difference between the means: this conforms with p > 0.05 for this variable (Table 1).