The purpose of this study was to evaluate the effect of exercise training intensity
relative to the ventilatory threshold (VT) on changes in work (watts) and V˙O2 at the ventilatory threshold and at maximal exercise in previously sedentary participants
in the HERITAGE Family Study. We hypothesized that those who exercised below their
VT would improve less in V˙O2 at the ventilatory threshold (V˙O2 vt) and V˙O2 max than those who tained at an intensity greater than their VT. Supervised cycle
ergometer training was performed at the 4 participating clinical centers, 3 times
a week for 20 weeks. Exercise training progressed from the HR corresponding to 55
% V˙O2 max for 30 minutes to the HR associated with 75 % V˙O2 max for 50 minutes for the final 6 weeks. VT was determined at baseline and after
exercise training using standardized methods. 432 sedentary white and black men (n
= 224) and women (n = 208), aged 17 to 65 years, were retrospectively divided into
groups based on whether exercise training was initiated below, at, or above VT. Results:
1) Training intensity (relative to VT) accounting for about 26 % of the improvement
in V˙O2 vt (R2 = 0.26, p < 0.0001). 2) The absolute intensity of training in watts (W) accounted for
approximately 56 % of the training effect at VT (R2 = 0.56, p < 0.0001) with post-training watts at VT (VTwatts ) being not significantly different than W during training (p > 0.70). 3) Training
intensity (relative to VT) had no effect on ΔV˙O2 max. These data clearly show that as a result of aerobic training both the V˙O2 and W associated with VT respond and become similar to the absolute intensity of
sustained (3 × /week for 50 min) aerobic exercise training. Higher intensities of
exercise, relative to VT, result in larger gains in V˙O2 vt but not in V˙O2 max.
Key Words:
Submaximal exercise, submaximal fitness, V˙O2 , race, sex.
References
sgaskill@selway.umt.edu.
