Hypothesis Whether increasing peak aerobic capacity for walking (V̇_2peak) by interval walking training (IWT) is closely linked with decreasing the indices of lifestyle-related diseases (LSDs) in middle-aged and older people were examined.

Methods For 4 months from April to September 2005 or 2006, 246 males and 580 females (∼65 years) performed IWT consisting of ≥5 sets of fast walking at ≥70% V̇_2peak for 3 min followed by slow walking at ≤40% V̇_2peak for 3 min ≥4 days/week. Before and after IWT, we measured V̇_2peak, body mass index (BMI), %body fat, arterial blood pressure, thigh muscle strength and blood parameters. We analysed 198 males and 468 females who had undergone all the measurements both before and after IWT. To examine the hypothesis, we divided the subjects equally into three groups according to their pretraining V̇_2peak: low, middle and high groups for each sex.

Results Before training, it was found that thigh muscle strength and blood high-density lipoprotein cholesterol concentration were lower, whereas body weight, BMI, %body fat, arterial blood pressure and blood glucose were higher in the low group than the high group (all, p<0.05). After training, although V̇_2peak and thigh muscle strength increased and body weight, BMI, %body fat, blood pressure and blood glucose concentration decreased in all groups (all, p<0.05), the changes were greatest in the low group for both sexes.

Conclusion V̇_2peak at baseline and changes in response to training were closely linked with indices of LSDs.