Personal, program-based, and environmental barriers to physical activity were explored among a U.S. population-derived sample of 2,912 women 40 years of age and older. Factors significantly associated with inactivity included American Indian ethnicity, older age, less education, lack of energy, lack of hills in one's neighborhood, absence of enjoyable scenery, and infrequent observation of others exercising in one's neighborhood. For all ethnic subgroups, caregiving duties and lacking energy to exercise ranked among the top 4 most frequently reported barriers. Approximately 62% of respondents rated exercise on one's own with instruction as more appealing than undertaking exercise in an instructor-led group, regardless of ethnicity or current physical activity levels. The results underscore the importance of a multifaceted approach to understanding physical activity determinants in this understudied, high-risk population segment.

Conclusions-Rural and urban women seem to face diVerent barriers and enablers to LTPA, and have a diVerent pattern of determinants, thus providing useful information for designing more targeted interventions. (J Epidemiol Community Health 2000;54:667-672) Physical inactivity is a major public health problem in the United States and other industrialised nations and is responsible for substantial disease burden.

IMPORTANCE Epidemiological evidence suggests that physical activity benefits cognition, but results from randomized trials are limited and mixed.OBJECTIVE To determine whether a 24-month physical activity program results in better cognitive function, lower risk of mild cognitive impairment (MCI) or dementia, or both, compared with a health education program. DESIGN, SETTING, AND PARTICIPANTSA randomized clinical trial, the Lifestyle Interventions and Independence for Elders (LIFE) study, enrolled 1635 community-living participants at 8 US centers from February 2010 until December 2011. Participants were sedentary adults aged 70 to 89 years who were at risk for mobility disability but able to walk 400 m. INTERVENTIONS A structured, moderate-intensity physical activity program (n = 818) that included walking, resistance training, and flexibility exercises or a health education program (n = 817) of educational workshops and upper-extremity stretching. MAIN OUTCOMES AND MEASURES Prespecified secondary outcomes of the LIFE study included cognitive function measured by the Digit Symbol Coding (DSC) task subtest of the Wechsler Adult Intelligence Scale (score range: 0-133; higher scores indicate better function) and the revised Hopkins Verbal Learning Test (HVLT-R; 12-item word list recall task) assessed in 1476 participants (90.3%). Tertiary outcomes included global and executive cognitive function and incident MCI or dementia at 24 months.RESULTS At 24 months, DSC task and HVLT-R scores (adjusted for clinic site, sex, and baseline values) were not different between groups. The mean DSC task scores were 46.26 points for the physical activity group vs 46.28 for the health education group (mean difference, −0.01 points [95% CI, −0.80 to 0.77 points], P = .97). The mean HVLT-R delayed recall scores were 7.22 for the physical activity group vs 7.25 for the health education group (mean difference, −0.03 words [95% CI, −0.29 to 0.24 words], P = .84). No differences for any other cognitive or composite measures were observed. Participants in the physical activity group who were 80 years or older (n = 307) and those with poorer baseline physical performance (n = 328) had better changes in executive function composite scores compared with the health education group (P = .01 for interaction for both comparisons). Incident MCI or dementia occurred in 98 participants (13.2%) in the physical activity group and 91 participants (12.1%) in the health education group (odds ratio, 1.08 [95% CI, 0.80 to 1.46]).CONCLUSIONS AND RELEVANCE Among sedentary older adults, a 24-month moderate-intensity physical activity program compared with a health education program did not result in improvements in global or domain-specific cognitive function.

Compared with general health education, a 12-month moderate-intensity exercise program that met current physical activity recommendations for older adults improved some objective and subjective dimensions of sleep to a modest degree. The results suggest additional areas for investigation in this understudied area.

Compared with nutrition participants (NU), exercise participants (EX) showed significant improvements in the following: total energy expenditure (baseline and post-test means [SD] for EX = 1.4 [1.9] and 2.2 [2.2] kcal/kg/day; for NU = 1.2 [1.7] and 1.2 [1.6] kcal/kg/day; p <.02); stress-induced blood pressure reactivity (baseline and post-test systolic blood pressure reactivity values for EX = 21.6 [12.3] and 12.4 [11.2] mm Hg; for NU = 17.9 [10.2] and 17.7 [13.8] mm Hg; p <.024); and sleep quality (p <.05). NU showed significant improvements in percentages of total calories from fats and saturated fats relative to EX (p values <.01). Both groups reported improvements in psychological distress. Conclusions. Family caregivers can benefit from initiating a regular moderate-intensity exercise program in terms of reductions in stress-induced cardiovascular reactivity and improvements in rated sleep quality.