Exercise intensity prescription in obese individuals

Area of Science:

• Exercise Physiology
• Obesity Research
• Cardiovascular Health

Background:

• Accurate exercise prescription is crucial for managing obesity.
• American College of Sports Medicine (ACSM) guidelines offer methods to determine exercise intensity using heart rate (HR) and oxygen uptake (VO2).
• The validity of these methods in obese populations requires further investigation.

Purpose of the Study:

• To evaluate the relationship between different ACSM-recommended exercise intensity prescription methods based on HR and VO2 in individuals with varying degrees of obesity.
• To determine the influence of obesity severity and resting HR on these relationships.

Main Methods:

• Sixty-eight obese adults were stratified into three Body Mass Index (BMI) groups.
• Subjects underwent a graded exercise test on a treadmill with a ramp protocol.
• Linear regressions were calculated to compare various HR-based intensity measures (%HR reserve, %maximal HR) against VO2-based measures (%VO2 reserve, %VO2 peak).

Main Results:

• The %HR reserve-%VO2 reserve regression showed partial agreement with the line of identity when all subjects were combined.
• Significant deviations from the line of identity were observed for %HR reserve-%VO2 peak, %maximal HR-%VO2 reserve, and %maximal HR-%VO2 peak regressions (P < 0.001).
• Obesity degree influenced %HR reserve-%VO2 regressions (approx. 15% variation), while resting HR significantly affected %maximal HR-%VO2 regressions (28-37% variation).

Conclusions:

• The relationship between exercise intensity methods using %HR reserve and %VO2 reserve/peak is influenced by the degree of obesity.
• Methods relying on %maximal HR are not significantly affected by obesity but are strongly influenced by resting HR.
• These findings highlight the need to consider individual factors like BMI and resting HR when prescribing exercise intensity for obese individuals using ACSM guidelines.