For obesity, what is the initial aerobic intensity expressed as a percentage of heart rate reserve (HRR)?

• A. 20-30% HRR
• B. 40-59% HRR
• C. 60-79% HRR
• D. 80-100% HRR

Answer: (B)

Starting intensity for aerobic training in individuals who are obese or deconditioned is guided by heart rate reserve and is kept in a light-to-moderate range. This balance supports safety and adherence while still providing a meaningful training stimulus to improve cardiovascular fitness and assist with weight management. Heart rate reserve is the difference between your maximum heart rate and your resting heart rate, and the target heart rate is found by adding a percentage of that reserve to the resting rate. For obesity, the recommended initial range is 40-59% of HRR.

To see how this works, imagine a resting heart rate of 70 bpm and an estimated max of 180 bpm. HRR = 180 - 70 = 110. The target range would be 70 + (0.40 × 110) = 114 bpm up to 70 + (0.59 × 110) ≈ 135 bpm. Starting at roughly 114–135 bpm during aerobic activity keeps the effort sustainable and safer, with room to progress as fitness improves. Higher ranges (60–79% or 80–100% HRR) would be more demanding and are typically introduced later as conditioning improves, while 20–30% HRR would be too easy to elicit meaningful change.