The factors affecting adherence to a long-term interval walking training program in middle-aged and older people.

No long-term exercise training regimen with high adherence and effectiveness in middle-aged and older people is broadly available in the field. We assessed the adherence to, and effects of, our long-term training program comprising an interval walking training (IWT) and an information technology network system and the factors affecting adherence. Middle-aged and older men and women [n = 696, aged 65 ± 7(SD) yr] underwent IWT. The subjects were instructed to repeat five or more sets of fast and slow walking for 3 min each at ≥70 and 40% peak aerobic capacity for walking (V̇O2peak), respectively, per day ≥4 days/wk for 22 mo. Adherence was assessed as training days accomplished relative to the target of 4 days/wk over 22 mo. The effects on the V̇O2peak and lifestyle-related disease score were evaluated every 6 mo. The independent factors affecting adherence were assessed by multiple-regression analysis after adjustment for baseline physical characteristics and other possible covariates, including vasopressin V1a receptor polymorphisms. The adherence over 22 mo averaged 70% and was highly correlated with a 13% reduction in the lifestyle-related disease score (R(2) = 0.94, P = 0.006) and with a 12% increase in V̇O2peak (R(2) = 0.94, P = 0.006). The major determinant of higher adherence was lower baseline body mass index (BMI) (P < 0.0001) and male sex (P < 0.0001). For men, in addition to BMI, nonsmokers (P = 0.031) and V1a receptor polymorphisms (P = 0.033) were independent determinants of higher adherence. Thus the long-term IWT program is an effective regimen. Moreover, baseline BMI and sex for all subjects, and smoking and V1a receptor polymorphisms for men, were associated with adherence.