A COMPARISON OF HR AND VO2 RESPONSES TO TREADMILL EXERCISE IN BLACK AND WHITE MEN.

Abstract

661 This study compared heart rate (HR) and oxygen consumption (VO2) responses to submaximal and maximal treadmill exercise between White (n=21) and Black (n=21) men aged 18-35 years. Maximal and submaximal steady-state HR and VO2 values during the last 30 s of each 3 min stage of a maximal graded exercise test (GXT) were used for statistical analysis. The Blacks were on the average 4 years older (p<.05) than their White counterparts but were similar (p>.05) in body mass index, height, weight, and resting blood pressure. There were no ethnic differences in maximal HR (Blacks = 193.6 ± 9.6 bpm, Whites = 194.3 ± 8.4 bpm) or VO2 (Blacks = 46.8 ± 5.6 ml·kg−1·min−1, Whites = 48.9 ± 8.5 ml·kg−1·min−1) values. There were no significant differences in HR or VO2 responses between the Blacks and Whites while walking at 3 mph, jogging at 6 mph, jogging at 6 mph at 3% grade, and jogging at 6 mph at 6% grade. Regressing submaximal absolute HRs against corresponding VO2 values resulted in coincidental (F(2, 151)=1.62, p>.05) regression lines for Blacks and Whites. The HR/VO2 relationships expressed as a percentage of maximal values were also similar (F(2, 151)=0.27, p>.05). The dispersement of data points about the regression line was greater in Blacks (r=.87, SEE=16.8 bpm) than for Whites (r=.92, SEE 13.8 bpm). We conclude that Black and White males of similar fitness levels had similar HR and VO2 responses to submaximal exercise on a treadmill. Supported by ACSM Foundation - Polar Research Grant