Age-related change in peak oxygen uptake and the association to change in cardiovascular risk factor levels. The HUNT Study, Norway
Authors: Letnes J.M , Dalen H , Aspenes S.T , Salvesen O , Wisloff U , Nes B 
Published: November 2020

Abstract

Background
Cardiorespiratory fitness (CRF) is established as an important prognostic factor for future health, and specifically for cardiovascular disease. Few large studies have examined the longitudinal change in the gold-standard measure of CRF, namely peak oxygen uptake (VO2peak), in free-living populations.

Purpose
To assess the age-related change in absolute and relative VO2peakin a previously healthy population sample, and to assess the influence of leisure-time physical activity (LTPA) on age-related change in VO2peak. Furthermore, we wanted to assess the association between longitudinal change of VO2peak and change of cardiovascular risk factor levels.

Methods
Participants in the third wave of the Nord-Trøndelag Health Study (HUNT3, 2006–2008) free from cardiovascular, malignant, and pulmonary disease, and no use of antihypertensive medication were invited to cardiopulmonary exercise testing (CPET). Of the 4,656 participants completing a VO2peak test in HUNT3 1,505 performed a second CPET in HUNT4 (2017–2019). Anthropometric measures, blood samples, and self-reported questionnaires for leisure-time physical activity (LTPA) e.g was gathered at both time points. Linear mixed models were used to explore absolute (L/min) and relative (mL/kg/min) changes in VO2peak by age, sex and LTPA. The effect of age, sex, and LTPA (low, moderate, or high intensity and minutes of LTPA per week) on change in VO2peak was explored, and age, sex, and baseline VO2peak-adjusted linear regression models (excluding participants with relevant medication use from analyses) were used to assess the effect of change in VO2peak on change of cardiovascular risk factors.

Results
Average 10-year decline in relative VO2peak was 3.9 mL/kg/min (10%) in women and 5.5 mL/kg/min (12%) in men, increasing from a mean 3% in those 20 to 30 years old to about 20% in those 70 to 80 years old. The same pattern of a non-linear, accelerating decline in VO2peak was also found in results from the linear mixed models as illustrated in Figure 1, with a steeper decline for men. Both minutes and intensity of LTPA was associated with higher absolute and relative VO2peak, but the effect of LTPA on age-related decline in VO2peak diminished with age. A lower decline in relative VO2peak was associated with favourable changes of HDL cholesterol, total cholesterol (and the ratio to HDL cholesterol), triglycerides, systolic and diastolic blood pressure, and resting heart rate.

Conclusions
The decline in absolute and relative VO2peak is non-linear, accelerates with age, and is more pronounced in men. LTPA attenuated the decline in VO2peak, but the effect diminished with high age. Maintaining VO2peak was associated with favourable changes in cardiovascular risk factor levels. Measures to maintain a higher VO2peak on the populational level may convey significant societal health benefits through cardiovascular risk reduction.
Figure 1

Funding Acknowledgement
Type of funding source: Public hospital(s). Main funding source(s): The Liaison Committee for Education, Research and Innovation in Central Norway