Are heart rate methods based on ergometer cycling and level treadmill walking interchangeable?

Interchangeability and optimization of heart rate methods for estimating oxygen uptake in ergometer cycling, level treadmill walking and running

Background

The heart rate (HR) method enables estimating oxygen uptake (V̇O₂) in physical activities. However, there is a paucity in knowledge about the interchangeability of this method when applied to cycling, walking and running. Furthermore, with the aim of optimization, there is a need to compare different models for establishing HR-V̇O₂ relationships.

Methods

Twenty-four physically active individuals (12 males and 12 females) participated. For each participant, two models of HR-V̇O₂ relationships were individually established in ergometer cycling, level treadmill walking and running. Model 1 consisted of five submaximal workloads, whereas model 2 included also a maximal workload. Linear regression equations were used to estimate V̇O₂ at seven intensity levels ranging between 25 and 85% of heart rate reserve (HRR). The estimated V̇O₂ levels were compared between the exercise modalities and models, as well as with data from a previous study.

Results

A high level of resemblance in estimated V̇O₂ was noted between running and cycling as well as between running and walking, with both model 1 and model 2. When comparing walking and cycling, the V̇O₂ levels for given intensities of %HRR were frequently slightly higher in walking with both models (range of significant differences: 5–12%). The variations of the estimated individual V̇O₂ values were reduced when using model 2 compared to model 1, both between and within the exercise modalities.

Conclusion

The HR method is optimized by more workloads and wider ranges. This leads to overall high levels of interchangeability when HR methods are applied in ergometer cycling, level treadmill walking and running.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01524-w.

Heart Rate Methods Can Be Valid for Estimating Intensity Spectrums of Oxygen Uptake in Field Exercise

Purpose

Quantifying intensities of physical activities through measuring oxygen uptake (V̇O₂) is of importance for understanding the relation between human movement, health and performance. This can in principle be estimated by the heart rate (HR) method, based on the linear relationship between HR and V̇O₂ established in the laboratory. It needs, however, to be explored whether HR methods, based on HR-V̇O₂ relationships determined in the laboratory, are valid for estimating spectrums of V̇O₂ in field exercise. We hereby initiate such studies, and use cycle commuting as the form of exercise.

Methods

Ten male and ten female commuter cyclists underwent measurements of HR and V̇O₂ while performing ergometer cycling in a laboratory and a normal cycle commute in the metropolitan area of Stockholm County, Sweden. Two models of individual HR-V̇O₂ relationships were established in the laboratory through linear regression equations. Model 1 included three submaximal work rates, whereas model 2 also involved a maximal work rate. The HR-V̇O₂ regression equations of the two models were then used to estimate V̇O₂ at six positions of field HR: five means of quintiles and the mean of the whole commute. The estimations obtained were for both models compared with the measured V̇O₂.

Results

The measured quintile range during commuting cycling was about 45–80% of V̇O₂max. Overall, there was a high resemblance between the estimated and measured V̇O₂, without any significant absolute differences in either males or females (range of all differences: −0.03–0.20 L⋅min^–1). Simultaneously, rather large individual differences were noted.

Conclusion

The present HR methods are valid at group level for estimating V̇O₂ of cycle commuting characterized by relatively wide spectrums of exercise intensities. To further the understanding of the external validity of the HR method, there is a need for studying other forms of field exercises.