Effect of individual characteristics and aerobic training on the %HRR-%V̇O₂R relationship

ABSTRACT

This study aimed to assess if, during incremental exercise, considering individual characteristics can make the relationship between the percentages of heart rate (HRR) and oxygen uptake (V̇O₂R) reserve either 1:1 or more accurate. Cycle ergometer data of the maximal incremental exercise tests performed by 450 healthy and sedentary participants (17-66 years) of the HERITAGE Family Study, grouped for sex, ethnicity, age, body fat, resting HR, and V̇O_2max, were used to calculate the individual linear regressions between %HRR and %V̇O₂R. The mean slope and intercept of the individual linear regressions of each subgroup were compared with 1 and 0 (identity line), respectively, using Hotelling tests followed by post-hoc one-sample t-tests. Two multiple linear regressions were also performed, using either the slopes or intercepts of the individual linear regressions as dependent variables and sex, age, resting HR, and V̇O_2max as independent variables. The mean %HRR-%V̇O₂R relationships of all subgroups differed from the identity line. Moreover, individual linear regression intercepts (8.9 ± 16.0) and slopes (0.971 ± 0.190) changed (p < 0.001) after 20 weeks of aerobic training (13.1 ± 11.1 and 0.891 ± 0.122). The multiple linear regressions could explain only 3.8% and 1.3% of the variance in the intercepts and slopes, whose variability remained high (standard error of estimate of 15.8 and 0.189). In conclusion, the %HRR-%V̇O₂R relationship differs from the identity line regardless of individual characteristics and their difference increased after aerobic training. Moreover, due to the high interindividual variability, using a single equation for the whole population seems not suitable for representing the %HRR-%V̇O₂R relationship of a given subject, even when several individual characteristics are considered.

Highlights

• The association between %HRR and %V̇O₂R is not 1:1 even when individuals are grouped by age, sex, ethnicity, body composition, HR_rest, and V̇O_2max.

• Using several subject characteristics to identify the individual’s %HRR-%V̇O₂R relationship does not meaningfully increase its prediction accuracy or reduce the interindividual variability of %HRR-%V̇O₂R relationships

• Using a single equation for the whole population is not suitable for representing the relationship of a given subject; hence, individual relationships should be preferred when prescribing the intensity of aerobic exercise.

• The individual %HRR-%V̇O₂R relationship should be periodically assessed due to the potential training induced changes in the relationship.

KEYWORDS:

• Exercise
• intensity
• heart rate
• oxygen uptake
• aerobic training

Acknowledgements

The authors would like to thank Mr. Timothy C. Bloom for his linguistic revision of the manuscript. The HERITAGE Family Study was supported by multiple grants from the NIH (R01HL45670, R01HL47323, R01HL47317, R01HL47327, R01HL47321). The authors would like to recognize the contributions of the late Dr Jack Wilmore and the late Dr Arthur Leon, both Principal Investigators, to the HERITAGE Family Study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by The HERITAGE Family Study was supported by multiple grants from the NIH : [Grant Number R01HL45670, R01HL47323, R01HL47317, R01HL47327, R01HL47321].