Ambulatory activity and simple cardiorespiratory parameters at rest and submaximal exercise.

The purpose of this study was to explore the relationship between objectively determined ambulatory activity and simple cardiorespiratory parameters (heart rate and blood pressure at rest and during submaximal exercise) in individuals who were stratified for self-reported participation (yes/any vs. no/none) in vigorous physical activity (PA). Ninety-eight subjects (African Americans: 7 M, 16 F; Caucasians: 33 M, 42 F; mean age 46.4 +/- 15.4 yrs; mean BMI 26.7 +/- 4.8) wore a pedometer for 21 consecutive days and completed a 10-min submaximal treadmill graded exercise test with HR (beats/min) and BP (mmHg) measured while walking at 4.8 km/hr and a 10% grade. Subjects averaged 7,618 +/- 3.045 steps/day. There were no differences in steps/day by self-reported vigorous PA strata. There was an inverse relationship (r = -0.35, p = 0.03) between steps/day and resting HR in subjects who reported no vigorous PA. There was an inverse relationship (r = -0.22, p = 0.04) between steps/day and submaximal HR in all subjects. When stratified for self-reported vigorous PA, the inverse relationship between steps/day and submaximal HR was stronger for those reporting no vigorous PA (r = -0.39, p = 0.01) vs. those reporting any vigorous PA (r = -0.28, p = 0.05). There was no relationship between steps/day and BP at rest or during exercise in this normotensive sample.