The purpose of this study was to determine whether adiposity affects the attainment of V˙O2max.
Sixty-seven male and 68 female overweight (body mass index (BMI) = 25-29.9 kg·m−2) and obese (BMI ≥ 30 kg·m−2) participants undertook a graded treadmill test to volitional exhaustion (phase 1) followed by a verification test (phase 2) to determine the proportion who could achieve a plateau in V˙O2 and other "maximal" markers (RER, lactate, HR, RPE).
At the end of phase 1, 46% of the participants reached a plateau in V˙O2, 83% increased HR to within 11 beats of age-predicted maximum, 89% reached an RER of ≥1.15, 70% reached a blood lactate concentration of ≥8 mmol·L−1, and 74% reached an RPE of ≥18. No significant differences between genders and between BMI groups were found with the exception of blood lactate concentration (males = 84% vs females = 56%, P < 0.05). Neither gender nor fatness predicted the number of other markers attained, and attainment of other markers did not differentiate whether a V˙O2 plateau was achieved. The verification test (phase 2) revealed that an additional 52 individuals (39%) who did not exhibit a plateau in V˙O2 in phase 1 had no further increase in V˙O2 in phase 2 despite an increase in workload.
These findings indicate that the absence of a plateau in V˙O2 alone is not indicative of a failure to reach a true maximal V˙O2 and that individuals with excessive body fat are no less likely than "normal-weight" individuals to exhibit a plateau in V˙O2 provided that the protocol is appropriate and encouragement to exercise to maximal exertion is provided.
1School of Human Movement Studies and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, AUSTRALIA; and 2School of Human Studies, University of Alabama at Birmingham, Birmingham, AL
Address for correspondence: Rachel E. Wood, Ph.D., Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Ave, Kelvin Grove, Brisbane, Queensland 4059, Australia; E-mail:firstname.lastname@example.org.
Submitted for publication January 2009.
Accepteid for publication July 2009.