PURPOSE: Habitual exercise is associated with marked reductions in both total and abdominal adipose tissue (AT), however, the optimal dose (amount and intensity) of exercise required to elicit the greatest reduction remains unclear. The purpose of this investigation is to determine the separate effects of increasing exercise amount and intensity on AT and skeletal muscle (SM) mass in sedentary, abdominally obese adults.
METHODS: Participants in this ancillary study included 105 men (40%) and women (60%) who were randomly assigned to one of four conditions for 24 weeks: control (C; n=20); low amount low intensity (LALI; 180 and 300 kcal/session for women and men, respectively, at 50% of VO2peak, n=24); high amount low intensity (HALI; 360 and 600 kcal/session for women and men respectively at 50% VO2peak, n=31); high amount high intensity (HAHI; 360 and 600 kcal/session for women and men, respectively, at 75% of VO2peak, n=30). AT and SM mass were measured by magnetic resonance imaging at baseline and 24 weeks.
CONCLUSION: Substantial reduction in visceral AT with a preservation of SM mass is observed independent of exercise amount and intensity, however, higher intensity (HAHI) may be more effective than guideline-recommended (LALI) exercise for reducing total and subcutaneous adiposity.