Date of Award
Doctor of Philosophy
Ann M. Swartz
Scott J. Strath, Christy Greenleaf, Renee Walker, Michael Brondino
Elderly, Exercise, Physical Activity
Research has begun to quickly emerge on the potential benefit of light intensity physical activity (LPA) to the health of adults. Little is known about LPA, and much of the current LPA research stems from sedentary behavior research. The purpose of this dissertation was to more fully understand, describe, and characterize potential health benefits of LPA by determining the prevalence, patterns, and health benefits of light intensity physical activity in older adults. Three individual studies were completed to address each portion of this purpose. Study 1: Light Intensity Physical Activity and Health in Adults: A Systematic Review. The purpose of this study was to critically examine the current literature pertaining to LPA and whether research supported a benefit or lack of benefit to adults. Upon search, five health categories emerged and were examined: 1) all cause mortality, 2) metabolic health, 3) cardiovascular health, 4) cancer risk, and 5) functional health. Overall findings suggested there may be benefit to incorporating LPA within the day in order to decrease risk of all-cause mortality, decrease insulin resistance, c-reactive protein, glucose, insulin, metabolic syndrome, physical function, and increase cognition. The results from this review suggested adults who were inactive, had been diagnosed with a chronic disease, or those who were older, showed a greater benefit to engaging in LPA than those who were healthy and physically active. Study 2: Contextual Analysis of Physical Activity. The second study was an observational study to describe the patterns and context of LPA in older adults by measuring their physical activity over seven days and the context of their LPA was recorded on one day for a simultaneous measurement. Our results suggested older adults engaged in over 250 min per day of LPA, in mostly short, frequent bouts (~2.5 min each bout). LPA was performed for a consistent 15-25 min each hour from 7am until 7pm. When activity domain was examined, over half of the activity occurred during participants’ leisure time. Popular specific activities included leisure-time activities such as multi-tasking while watching television or on the computer, shopping, and household activities such as cooking and cleaning. Contextual measurement revealed the LPA was more commonly performed inside when the participant was by themselves, as opposed to with a group. Understanding what LPA activities are already prevalent and specific to older adults, the social support necessary to elicit the behavior, and the location these activities most commonly occur to help identify potential barriers to the activity prescription (weather, transportation, resources, etc.). Study 3: Dose response to LPA and glucose dynamics in older adults. The purpose of this study was to determine whether there was a dose-response relationship between the total amount of time spent in LPA and post-prandial glucose response in older adults. Results from these trials showed there was a significant decrease in glucose area under the curve 3-hours post-meal when 40% of the measured time was spent in LPA. This effect was further compounded when time spent in LPA was increased to 60% of the measurement period. This study was one of the first with an explicit focus on LPA and provides evidence there is a metabolic health benefit to engaging in LPA, that can further increase in benefit with increasing time spent in lower intensity activities. Overall Conclusion. Together these studies provide evidence that LPA may be a feasible physical activity selection for older adults and these active behaviors, even at low intensities, may be health enhancing. Study 1 provides a solid foundation to understand what we already know by what has been published in the literature, Study 3 answered the question of whether or not LPA would provide a sufficient stimulus to alter glucose uptake and further still whether that response would be dose-dependent, and Study 2 results will assist health and fitness professionals and researchers in designing and developing appropriate LPA prescriptions. As our results directed, activity data from objectively measured LPA showed LPA activities, therefore prescription development, are not synonymous with moderate and vigorous activities and therefore should be considered individually. These outcomes provide an important, positive impact on population health by providing evidence for older adults to be physically active through a potentially more attainable approach in order to gain health benefits.
Welch, Whitney A., "An Examination of Light Intensity Physical Activity and Health in Older Adults" (2016). Theses and Dissertations. 1319.