Active Voice: Physical Activity for Healthy Aging: The Intensity Matters for Combating Chronic Inflammation in Older Adults
By Andreas Nilsson, M.P.H., Ph.D.
Andreas Nilsson, M.P.H., Ph.D., is a researcher and senior lecturer at the Department of Health Sciences, University of Örebro, Sweden. He is a physical activity epidemiologist. His research focus relates to the influence of physical activity behaviors on inflammation and metabolic health in older adults. Dr. Nilsson’s investigational work includes both observational studies and behavioral interventions.
This commentary presents the author’s views on the topic of his research article, which was published with co-authors in the July 2018 issue of Medicine & Science in Sports & Exercise® (MSSE).
The occurrence of low-grade chronic systemic inflammation is a condition contributing to health deterioration during aging. Systemic inflammation is age-related, and older individuals generally spend more time in sedentary behaviors and less time in health-enhancing physical activity compared to younger individuals. Taken together, these factors contribute to development of metabolic disorders in the elderly.
While the beneficial effects of physical activity on markers for cardiovascular and metabolic health are well established, corresponding effects on markers of systemic inflammation remain less clarified. Although inflammatory processes may play an important role in the development of both cardiovascular and metabolic diseases, surprisingly few studies have examined how different physical activity behaviors may influence inflammatory status in older adult populations. This knowledge gap is unfortunate, as increased understanding of such relationships has clear public health implications and could aid in further developing guidelines on physical activity behaviors to promote healthy aging. We conducted a study to examine some of these issues and reported our findings in the July 2018 issue of MSSE. In our investigation, we examined the influence of objectively assessed time spent in sedentary behavior and in different intensities of physical activity on levels of both pro- and anti-inflammatory markers in 111 older (65 to 70 years) community-dwelling women.
Daily time spent in sedentary behavior, and in both light and moderate-to-vigorous intensity physical activity, was assessed with accelerometers. All subjects completed a health examination, where circulating levels of acute-phase proteins (C-reactive protein [CRP], fibrinogen and the adipokine adiponectin) were derived from venous blood samples. By the use of regression analysis, we analyzed the effects of replacing a 30-minute period of sedentary behavior with a corresponding time period of physical activity in either light or moderate-to-vigorous intensity on the different inflammatory markers.
The results showed that replacing 30 minutes of sedentary behavior with the same amount of time in physical activity of at least moderate intensity (e.g., brisk walking) was associated with a significant reduction in levels of both pro-inflammatory markers CRP and fibrinogen. Interestingly, in the regression model, the effect on fibrinogen remained statistically significant when time in sedentary behavior was replaced with time in physical activity of intensities that were below the moderate-intensity threshold. Our data further showed that replacing 30 minutes of physical activity time in light intensity with the same amount of time in moderate intensity activity (e.g., increasing the pace of walking, from slow to brisk) also was associated with a reduced CRP level; this was true even when the amount of daily time spent sedentary was held constant. Thus, this influence on CRP level seems driven by physical activity intensity rather than variations in amount of time spent sedentary.
Another important aspect of our findings is that the beneficial effects on inflammation level by physical activity behavior were evident in all women regardless of their metabolic risk factors, i.e., constituents of the metabolic syndrome. This further strengthens the proposition that adopting a physically active lifestyle promotes health in older adults at different stages of metabolic health.
It is interesting to note that physical activity behavior had no impact on circulating adiponectin levels in our study. This may not be surprising given that levels of adiponectin are mainly driven by level of adiposity. Further research will be needed to elucidate mechanisms by which physical activity may act on biomarkers with anti-inflammatory properties.
Our research supports the existence of different intensity thresholds by which physical activity influences important clinical markers of systemic inflammation in older women — regardless of their status on metabolic health.