Is there an association between total physical activity level and VO_2max among fitness club members? A...

Since cardiorespiratory fitness is an important predictor for all-cause mortality, it is of interest to know if meeting the physical activity (PA) recommendations is associated with higher levels of maximal oxygen uptake (VO_2max). We aimed to investigate the association between total PA level given as counts per minute (cpm) and minutes in moderate-to-vigorous PA (MVPA), and VO_2max in new fitness club members.

A total of 62 men and 63 women (≥ 18 years), defined as healthy (no disease considered to hinder PA) participated in this study. VO_2max (mL kg^-1 min^-1) was measured with a cardiopulmonary exercise (modified Balke protocol), and total PA level was measured with ActiGraph GT1M for seven consecutive days. All participants accumulating ≥ 10 h of activity recordings ≥ 4 days were included in the data analysis. To examine associations between PA level and VO_2max, a Pearson correlation and a multiple linear regression analysis adjusted for covariates were used.

VO_2max (mL kg^-1 min^-1) was 40.5 ± 7.2 in men and 35.1 ± 6.0 in women. Total PA level (cpm) and MVPA (min) were 352.4 ± 123.4 and 260.0 ± 132.6 in men and 361.4 ± 103.8 and 273.2 ± 137.0 in women. Total PA level (men: r = 0.346, p < 0.01, women: r = 0.267 p < 0.01) and MVPA (men: r = 0.359, p =  < 0.01, women: r = 0.236, p = 0.03) was associated with VO_2max. When adjusting for age and body fat percentage, total PA level and MVPA were no longer associated with VO_2max (men: p = 0.11 and p = 0.79, women: p = 0.40 and p = 0.61). In men, age (β = - 0.469 p < 0.01) and body fat percentage (β = - 0.483, p < 0.01) were the strongest predictor for VO_2max. For women, body fat percentage was the strongest predictor for VO_2max (β = - 0.483, p < 0.01).

Total PA level and MVPA were associated with VO_2max, but the association was low and diminished when adjusted for age and body fat percentage. Body fat percentage (men and women) and age (men) were more strongly associated with VO_2max than total PA level and MVPA.