Ambulatory activity and simple cardiorespiratory parameters at rest and submaximal exercise

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Public Health

Background:

• Objective measurement of ambulatory activity is crucial for understanding physical activity's impact on health.
• Cardiorespiratory parameters like heart rate and blood pressure are key indicators of cardiovascular fitness.
• The relationship between daily step counts and cardiorespiratory health, especially when stratified by self-reported vigorous physical activity (PA), requires further investigation.

Purpose of the Study:

• To examine the association between objectively measured daily steps and resting/submaximal cardiorespiratory measures.
• To determine if this association differs between individuals who do and do not report vigorous physical activity.

Main Methods:

• Ninety-eight adults (mean age 46.4 years) wore pedometers for 21 days to measure daily steps.
• Subjects underwent a submaximal treadmill exercise test with heart rate (HR) and blood pressure (BP) monitoring.
• Participants were stratified based on self-reported engagement in vigorous physical activity (PA).

Main Results:

• No significant difference in daily steps was found between groups reporting any or no vigorous PA.
• A significant inverse relationship existed between daily steps and resting heart rate for those reporting no vigorous PA (r = -0.35, p = 0.03).
• An inverse relationship was observed between daily steps and submaximal heart rate across all subjects (r = -0.22, p = 0.04), which was stronger in the no vigorous PA group (r = -0.39, p = 0.01).

Conclusions:

• Objectively measured daily physical activity, even without vigorous exertion, is inversely related to resting and submaximal heart rate.
• This relationship is more pronounced in individuals who do not engage in regular vigorous physical activity.
• Daily step counts may serve as a valuable, accessible indicator of cardiorespiratory health.