834. Health Benefits of Light-Intensity Physical Activity: A Systematic Review of Accelerometer Data of the National Health and Nutrition Examination Survey (NHANES)
Commentary by Lee Goodwin, Research Associate at the Institute of Sport Science and Sport, Friedrich-Alexander University Erlangen-Nuremberg, Germany
This systematic review builds strongly on the growing evidence to support the health benefits of light-intensity physical activity (LIPA). With guidelines centring on moderate to vigorous physical activity (MVPA), no form of recommendation in the scope of low-intensity activity is currently provided. The authors aimed to shed light on the little-known effects of LIPA by identifying and assessing data from The National Health and Nutrition Examination Survey (NHANES). The NHANES database was chosen due to the availability and volume of standardised device-based physical activity and health outcome data. Thus, the systematic review investigated the relationship between device-based LIPA and modifiable health outcomes in adults and older adults within NHANES, with the aim to provide further clarity regarding the promotion of LIPA.
Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the PubMed, EMBASE, Web of Science and Google Scholar databases were systematically searched for relevant peer-reviewed literature from the period of 2007 until March 2016. A total of 40 studies were identified for final inclusion. 37 studies were cross-sectional and focused on the effects of LIPA on a modifiable health outcome. Three studies were longitudinal and investigated the association of LIPA with mortality.
Findings showed that LIPA was beneficially associated with several important markers of cardiometabolic health and mortality in healthy adults and older adults, as well as in some diseased populations. In line with previous studies, beneficial associations were shown between LIPA and insulin sensitivity, measures of adiposity, and metabolic diseases. Data on LIPA and cardiometabolic health outcomes were richer than that of LIPA and musculoskeletal outcomes. Results also pointed towards the benefits of LIPA regarding the improvement of depressive syndromes. However, findings revealed uncertainty regarding favourable health outcomes in diseased populations. For example, a beneficial relationship was seen to exist between LIPA and adiposity in patients with COPD, but not in cancer survivors.
Regarding the biological health constructs of LIPA, the authors stated that activity intensity may not be the driving force in the occurrence of favourable health outcomes. Instead, emphasis was placed on activity duration as an influential factor in beneficial metabolic response, with low-intensity activity able to withstand lengthier time periods than activities of higher intensity. From a dose-response perspective, the durable effects of LIPA could thus serve as a protective mechanism in the context of weight gain. Important to note, however, is that high intensity LIPA had a much more positive impact on cardiometabolic markers than low intensity LIPA.
Key study limitations referred to the analysis and interpretation of accelerometer data, study type and comparability of studies from the NHANES database, and low study adjustment for both MVPA and sedentary behaviour. Overall, evidence on the beneficial effects of LIPA continues to expand. Further research is required in the form of longitudinal observational studies and intervention trials. Should such studies confirm the findings of the current study, the integration of LIPA in physical activity recommendations might be warranted. The authors stress that those inactive and insufficiently active should at least be addressed with regard to LIPA in physical activity recommendations.
Source: Sports Medicine, 2017, First Look. Access to this article may depend on your Institutional rights: Access the full article.