Cardiovascular responses in black and white males during exercise

Area of Science:

• Exercise Physiology
• Cardiovascular Research
• Racial Differences in Physiology

Background:

• Previous studies indicate lower resting heart rate (HR) in Black individuals compared to White individuals.
• Understanding cardiovascular responses across different racial groups during exercise is crucial for personalized health insights.

Purpose of the Study:

• To investigate if the lower resting heart rate (HR) difference between Black and White males persists during submaximal exercise.
• To compare other cardiovascular responses, including oxygen consumption and cardiac output, during submaximal exercise in Black and White males.

Main Methods:

• Sixteen Black and 16 White males, matched for age, body surface area, and maximal oxygen consumption, performed exercise at 0, 50, and 100 W on a cycle ergometer.
• Heart rate (HR), oxygen consumption, and cardiac output were measured at rest and at each work rate.
• Stroke volume was calculated, and blood pressure was also assessed.

Main Results:

• Oxygen consumption was not significantly different between Black and White males at rest or during any work rate.
• Cardiac output showed no statistically significant differences between the groups at rest or during exercise.
• Heart rate (HR) was significantly lower in Black males compared to White males at rest and all tested work rates.
• A trend towards higher stroke volume was observed in Black males compared to White males at rest and during exercise.

Conclusions:

• The significantly lower heart rate (HR) observed in Black males compared to White males extends to submaximal exercise.
• The cardiovascular system in Black males appears to compensate for lower heart rates with a potentially higher stroke volume during exercise.
• No significant differences in oxygen consumption, cardiac output, or resting blood pressure were found between the groups.