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

Area of Science:

• Exercise Physiology
• Biomedical Engineering
• Cardiovascular Dynamics

Background:

• Understanding heart rate (HR) response dynamics is crucial for designing effective exercise protocols and control systems.
• Previous research has explored HR responses to exercise, but direct comparisons between cycle ergometry and treadmill testing are limited.

Purpose of the Study:

• To compare the time constant of heart rate (HR) dynamics between cycle ergometer (CE) and treadmill (TM) exercise.
• To assess the implications of these dynamics for model-based HR controller design.

Main Methods:

• Twenty-five healthy males performed square-wave exercise tests on both CE and TM.
• The time constant of HR dynamics was estimated for each modality.
• Root-mean-square model error was calculated to assess model fit.

Main Results:

• No significant difference was found in the time constant of HR dynamics between CE and TM at a perceived exertion of 13 (68.7s ± 21.5s vs. 62.5s ± 18.5s, p=0.20).
• A trend suggested higher root-mean-square error for CE (2.5 bpm ± 0.5 bpm) compared to TM (2.2 bpm ± 0.5 bpm, p=0.059).
• This difference may be linked to lower mean HR on CE for equivalent perceived exertion.

Conclusions:

• The dynamic HR response to exercise is comparable between CE and TM, supporting the use of similar control strategies.
• Model-based HR controllers can potentially be applied to both exercise modalities with adjustments for steady-state gains.
• This research aids in the development of adaptive physiological control systems for exercise rehabilitation and training.