Ventilatory Threshold Related to V̇O 2 reserve, Heart Rate Reserve, and Rating of Perceived Exertion in a Large Varied Sample

Abstract

Purpose: ACSM guidelines state that aerobic exercise intensity should be 30%/40% to 89% V̇O 2 reserve (V̇O 2 R) or heart rate reserve (HRR). Determining the proper intensity within this range is the "art" of exercise prescription, often relying on rating of perceived exertion (RPE) as the adjunctive intensity modulator. Current guidelines do not consider the use of ventilatory threshold (VT) due to the need for specialized equipment and methodological issues. The purpose of this investigation was to evaluate VT related to V̇O 2peak , V̇O 2 R, HRR, and RPE across the full spectrum of very low to very high V̇O 2peak values.

Methods: Eight hundred and sixty-three records of exercise tests were retrospectively examined. Data were stratified for V̇O 2peak , activity level, age, test modality, and sex.

Results: When stratified for V̇O 2peak , V̇O 2 at VT (V̇O 2 vt) had a lower mean value of ~14 mL·kg -1 ·min -1 in the lowest fit, rose gradually until median V̇O 2peak , and rose steeply thereafter. When graphed relative to V̇O 2peak , V̇O 2 vt as a percentage of V̇O 2 R (VT%V̇O 2 R) resembled a U-shaped curve, with a nadir ~43% V̇O 2 R at V̇O 2peak ~40 mL·kg -1 ·min -1 . Average VT%V̇O 2 R increased to ~75% in groups with the lowest or highest V̇O 2peak . There was a large variance in the value of VT at all V̇O 2peak levels. Mean RPE at VT was 12.5 ± 0.93, regardless of V̇O 2peak .

Conclusions: Given the relationship of VT as the transition from moderate- to higher-intensity exercise, these data may help the understanding of aerobic exercise prescription in persons across the spectrum of V̇O 2peak values.

Figure 1.. The relationship of V.O2vt, VT%V.O2R, RPE12V.O2 and RPE12%V.O2R with V.O2peak for all 863 participants.

A) $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$vt vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak. B) Ventilatory threshold $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$ as a percentage of $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R (VT%$\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R) vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak. C) $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$ at RPE 12 (RPE12$\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$) vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak. D) $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$ at RPE12 as a % of $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R (RPE12%$\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R) vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak. Regression lines reflect 2^nd degree polynomials with prediction equations and R values shown on graphs. The dashed boxes on panels B and D represent 40-59% $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R.

Figure 2.. The relationship of V.O2vt and VT%V.O2R with V.O2peak, color-stratified for fitness level.

A) $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$vt vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak are plotted for all 863 participants and color-stratified to fitness level. B) VT%$\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$R vs. $\stackrel{.}{\mathrm{V}}{\mathrm{O}}_2$peak are plotted for all 863 participants and color-stratified to fitness level. Regression lines reflect 2^nd degree polynomials and logrhythmic expressions.