Does Exercise Intensity Matter?

Which is more important: exercise amount (i.e., duration) or exercise intensity? To investigate this issue, researchers conducted a 6-month trial in which 300 abdominally obese adults were randomized to one of four groups:

• Control group: maintain baseline activity level

• Low-low group: low-amount (≈30 minutes), low-intensity (50% of maximum oxygen consumption [VO₂ peak]) exercise

• High-low group: high-amount (≈60 minutes), low-intensity (50% of VO₂ peak) exercise

• High-high group: high-amount (≈40 minutes), high-intensity (75% of VO₂ peak) exercise

All exercise groups received five sessions weekly of the assigned intervention.

At 24 weeks, mean waist circumference was smaller (by about 4 cm) and mean weight loss was greater in the three exercise gro…