Validity of measures to indirectly determine maximal oxygen uptake in healthy and clinical subjects

Abstract

Abstract Background The peak oxygen uptake (VO2peak) is considered the most reliable parameter for evaluating cardiorespiratory fitness and guiding physical training. However, not everyone has access to VO2peak measurements. As a more accessible alternative, heart rate (HR) variables have emerged. Aim To explore the correlation between HR responses during rest, exercise, recovery, and VO2peak. Methods Thirteen healthy men participated in the study. Resting HR variability and parameters were recorded for 10 minutes using a heart rate monitor while participants were seated. A maximal intermittent treadmill test was conducted to determine the maximum rate of HR increase (rHRI) and obtain VO2peak data (33.53 ± 8.22 mL/kg/min). The test speed was set based on the International Physical Activity Questionnaire (IPAQ) classification: 8 km/h for inactive or insufficiently active individuals, and 10 km/h for active and highly active individuals. Additionally, HR recovery (HRR) was measured during a 10-minute seated recovery period. Results Significant correlations were observed between resting HR (r = -0.78, p = 0.001), average RR interval (iRR) (r = 0.73, p = 0.004), percentage of iRR differences exceeding 50 ms (pNN50) (r = 0.64, p = 0.001), HR (r = -0.60, p = 0.003), and VO2peak. However, no significant correlation was found between rHRI and VO2peak (r = 0.38, p = 0.2). Conclusion Resting HR parameters, HR variability, and HRR showed significant associations with VO2peak. These HR variables can be useful alternatives for assessing and prescribing physical training when direct measurement of VO2peak is not feasible.