Publish Date: Sunday, May 01, 2005
534 Board #125 2:00 PM - 3:30 PM Medicine & Science in Sports & Exercise: Volume 37(5) Supplement May 2005 p S101. The ACSM Guidelines advocates the use of a percentage of the maximal oxygen uptake reserve (%VO2R) for exercise prescription purposes because it's thought to provide a closer match with percentage of maximal heart rate reserve (%MHRR) than a given percentage of maximal VO2. However, some recent studies have challenged the validity of this matching, and more data is needed to assess whether other fitness-related characteristics affect this matching. PURPOSE: To assess the association of body mass index (BMI) with the matching of %MHRR and %VO2R during graded exercise testing (GXT). METHODS: The study sample included 434 adults (162 men; 274 women; mean age of 44±12 years; mean BMI of 28.0±5.8 kg/m2) who completed a maximal treadmill test to volitional fatigue using the BSU/Bruce Ramp protocol. The distribution of BMI measures within the sample was 32% <25.0; 36% between 25.0 and 29.9; and 32% >30. Subjects were excluded from the analysis if they failed to achieve a peak RER <1.0 during the GXT. Heart rate and VO2 data from minutes 3, 6 and 9 where converted into %MHRR and %VO2R, with 3.5 ml/kg/min serving to represent resting VO2 for calculation of VO2R. RESULTS: The relative exercise intensity for minutes 3, 6 and 9 represented 40±11, 63±15 and 83±12 of %VO2R, respectively. The %VO2R significantly underestimated %MHRR at each measurement point during the GXT with mean differences of -4.0, -2.3 and -4.4%, respectively (p <0.001), at minutes 3, 6 and 9. The association of BMI with the matching of %MHRR and %VO2R was assessed by correlation with the difference between %MHRR and %VO2R (ÄHRR-VO2R) at each stage of the GXT. Correlations for BMI and ÄHRR-VO2R were 0.001, -0.07 and -0.152, for minutes 3, 6 and 9, respectively. CONCLUSION: These results demonstrate that %VO2R significantly underestimates %MHRR within the relative intensity range typically used for exercise prescription, however, the mismatching observed within this sample was not significantly associated with BMI. ©2005 The American College of Sports Medicine
Presentation Detail
Author
Co-Presenter(s)
Laura M. Thatcher
Mitchell H. Whaley, Mitchell FACSM
Mitchell H. Whaley, Mitchell FACSM
Location
Nashville, TN
