Longitudinal changes in physical activity levels over 5 years and relationship to cardiorespiratory fitness in Chinese midlife women.

AIM: Better understanding the impact of changes in physical activity levels on cardiorespiratory fitness, as measured by maximal oxygen uptake (VO(2max)) may inform preventive interventions. We aimed to determine longitudinal changes in physical activity levels over 5 years and the relationship between these changes with VO(2max) in a sample of Chinese midlife women. METHODS: A total of 184 Chinese women aged 50-64 years in Hong Kong were enrolled for this study. Physical activity was assessed with the modified Chinese Baecke questionnaire at baseline (2002-2004) and follow-up (2008-2009). VO(2max) was measured with a symptom-limited maximal exercise test on an electrically braked cycle ergometer at follow-up. RESULTS: Compared with subjects who were persistently inactive, those who were increasingly/persistently active had significantly higher levels of VO(2max) (P<0.05). Being persistently active was also independently associated with a high level of VO(2max) (OR: 4.4, 95%CI: 1.0-19.2). However, the rate of decline in VO(2max) with age was apparently greater in persistently active subjects compared with their persistently inactive peers, but the differences were not statistically significant. CONCLUSION: Our findings suggest that maintaining a high level of physical activity may lead to higher levels of VO(2max).