Key result
Time-varying models demonstrated a significant slowing down of heart rate and oxygen uptake dynamics from the start of incremental exercise to exhaustion (p<0.01).
Observational (n=931)
No
p-value: p=<0.01
Low-complexity linear model structures with time-varying parameters can accurately capture non-linear cardiorespiratory responses during exercise from rest to exhaustion and recovery.
May enhance exercise test interpretation; hypothesis-generating and requires validation before clinical or prognostic use.
Biological systems have the ever-intriguing capacity to deal with disturbances and challenges from their environment. Exercise and sports are no different when it comes to studying systems (i.e. the human body) under stress. The goal of this study is to model the dynamic responses of heart rate (HR) and oxygen uptake (⩒O2) during incremental exercise tests, and identify changes in the characteristic response time and amplitude gain. Therefore, we study data of 992 maximal effort running tests from an open access dataset. First order autoregressive-exogenous (ARX) models with time-varying parameters accurately fit the data (R² > 0.98) and indicate overall faster dynamics for ⩒O2in comparison to HR. Furthermore, the models demonstrate significant slowing down of these dynamics at exhaustion and during the first moments of recovery for both physiological variables. In addition, the (steady state) gain values for HR and ⩒O2decrease from start to end of the test. Finally, small but significant linear correlations are found between the model characteristics and ⩒O2max of the test subjects. The results illustrate that using low-complexity linear model structures with time-varying parameter estimates allows for capturing important non-linear behaviour of cardiorespiratory responses during exercise from rest to exhaustion and recovery afterwards.
No takes yet. Share an insight, caveat, or question.
Gielen et al. (2023) conducted an observational in Healthy individuals undergoing exercise testing (n=931). Maximal effort incremental running test vs. Start of test (baseline) was evaluated on Change in time constant (TC) of heart rate and oxygen uptake from start to end of exercise (p=<0.01). Time-varying models demonstrated a significant slowing down of heart rate and oxygen uptake dynamics from the start of incremental exercise to exhaustion (p<0.01).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: