| The purposes of the thesis were: to describe leisure time physical activity (LTPA) patterns in a sample (n = 373) of mobile independent older men and women (ages 55 to 86 years), to evaluate the relationship between LTPA and fitness, and to identify, from a longitudinal analysis, explanatory variables of dependence in older age. Levels of LTPA were unrelated to age. Average daily activity included approximately 45 minutes of accumulated moderate and heavy activity. Although this activity meets the recommendation of 30 minutes of accumulated daily moderate activity, it was not adequate to stave off age-related reductions in fitness (cardiorespiratory, muscle strength and joint flexibility). Multiple regression analyses of the relationship of LTPA with VO2max, strength and flexibility showed that participation in LTPA was not a significant explanatory variable (and contributed less than 1% to the explained variance) of each of the fitness measures. In an eight-year follow-up of the original independent sample (ages 63 to 94 years), loss of independence was identified in 43 subjects, with 188 remaining independent. Multiple logistic regression analysis showed that after controlling for age, gender, disease, education and depression, the level of cardiorespiratory fitness (VO2max) eight years earlier was a significant determinant of the odds of becoming dependent. An odds ratio of 0.86 suggests that a greater VO2max of 3 or 4 ml kg-1 min-1 reduces the odds of becoming dependent by approximately 50%. Thus, cardiorespiratory fitness, but not the volume of leisure time physical activity was related to the outcome of future dependence. An increased cardiorespiratory fitness is an important aspect of maintaining independence in older age. |
