Reference values for estimated VO2max by two submaximal cycle tests: the Åstrand-test and the Ekblom-Bak test

Abstract

Aims: Submaximal tests estimating VO₂max have inherent biases; hence, using VO₂max estimations from the same test is essential for reducing this bias. This study aimed to establish sex- and age-specific reference values for estimated VO₂max using the Åstrand-test (Å-test) and the Ekblom-Bak test (EB-test). We also assessed the effects of age, exercise level, and BMI on VO₂max estimations.

Methods: We included men and women (20-69 years) from the Swedish working population participating in Health Profile Assessments between 2010 and 2020. Excluding those on heart rate-affecting medicines and smokers, n = 263,374 for the Å-test and n = 95,043 for the EB-test were included. VO₂max reference values were based on percentiles 10, 25, 40, 60, 75, and 90 for both sexes across 5-year age groups.

Results: Estimated absolute and relative VO₂max were for men 3.11 L/min and 36.9 mL/min/kg using the Å-test, and 3.58 L/min and 42.4 mL/min/kg using the EB-test. For women, estimated absolute and relative VO₂max were 2.48 L/min and 36.6 mL/min/kg using the Å-test, and 2.41 L/min and 35.5 mL/min/kg using the EB-test. Higher age (negative), higher exercise level (positive), and higher BMI (negative) were associated with estimated VO₂max using both tests. However, explained variance by exercise on estimated VO₂max was low, 10% for the Å-test and 8% for the EB-test, and moderate for BMI, 23% and 29%.

Conclusion: We present reference values for estimated VO₂max from two submaximal cycle tests. Age, exercise, and BMI influenced estimated VO₂max. These references can be valuable in clinical evaluations using the same submaximal tests.

Keywords: Cardiorespiratory fitness; Reference values; Submaximal test; VO2max.