Physical Activities/Baltimore Longitudinal Study Aging

Aging

Investigators

Linked publications & trials

Abstract

Over the past several years, we have studied self reported levels of physical activity in the Baltimore Longitudinal Study of Aging (BLSA) subjects. Increasing age is associated with a decline in physical activity, cardiovascular fitness, muscle strength, and muscle mass. These changes contribute to sarcopenia and frailty in the elderly. We have been interested in how changing physical activity impacts on these other activity related processes. Over the past year, we have completed an evaluation of self-reported falls in BLSA subjects. Falls in older people have been characterized extensively in the literature, however little has been reported regarding falls in middle-aged and younger adults. We compared falls in three age groups of subjects, young 20-45 years), middle-aged (46-65 years) and older (>65 years) men and women. The reporting of falls increased with age from 18% in young, to 21% in middle aged and 35% in older adults, with higher rates in women than men. Ambulation was cited as the cause of the fall most frequently in all gender and age groups. An injury of some type was reported in 70% of subjects. The young group reported injuries most frequently to wrist/hand, knees and ankles; the middle-aged to their knees and the older group to their head and knees. Women reported a higher percentage of injuries in all age groups. This is the first study that we are aware of to compare falls in young, middle and older aged men and women. Significant differences were found between the three age groups with respect to number of falls, activities engaged in prior to falling, perceived causes of the fall and where they fell. A second study examined the impact of longitudinal patterns of leisure time physical activity (LTPA) on mortality. Higher levels of leisure time physical activity (LTPA) are associated with reduced mortality. However it is unclear how changes in LTPA over time impact all cause mortality in men and women. Men (n=1316) and women (n=776) aged 19-90+ years from the BLSA were assessed for LTPA at baseline and at ~2 year intervals over a mean follow-up of 21.2 + 9.4 yr for men and 10.2 +5.6 yr for women. Death occurred in 538 men (40.9%) and 90 women (11.6%). LTPA was derived from self-reports of time spent in 97 activities converted into MET-minutes per 24 hours and was further grouped into high (>6 METs), moderate (4-5.9 METs) and low intensity LTPA (<4 METs). In younger (<70 years) men, those who reported improvement or negligible declines in total and high intensity LTPA had lower all cause mortality compared to those with greater declines in LTPA, independent of serum cholesterol, body mass index, hypertension and smoking status. In older (>70 years) men, the association between rate of change in high intensity LTPA and mortality was similar to that seen in younger men. Cross-sectional age patterns for women showed no difference in rates of change in total, high, or low intensity LTPA between survivors or decedents; however older (>70 years) decedents decreased their moderate intensity LTPA as compared to survivors. For women, longitudinal analyses showed neither rates of change in total, high, moderate nor low intensity LTPA were predictive of mortality. In this health-conscious population, greater longitudinal declines in total and high intensity LTPA are independent predictors of all cause mortality in men but not women. The observations in women are not consistent with other studies and may relate to low power due to relatively few deaths in the women over the follow up. The observations in men argue that the maintenance of a physical activity level is important for longevity. How to increase participation in physical activity has become a major health issue. The answer will lie in offering a variety of programs that allow for individualization. At present, a project is underway where we are using the same strategy and applying it to military reservist who do not meet fitness requirements for a 2 mile run. The goal is to increase their overall activity levels by making them more aware of what they are actually performing, and to set reasonable goals to increase activity during the course of their busy schedules.