1. While both moderate and vigorous activity are associated with health benefits, vigorous activity was associated with an additional mortality benefit in middle to older Australians this study.
Evidence Rating Level: 2 (Good)
Study Rundown: While widely accepted that physical activity is beneficial for health maintenance, it is unclear whether different activity levels confer different benefits. Though a longer period of moderate intensity exercise may result in the same energy expenditure as a shorter period of high intensity exercise, previous studies have shown that vigorous activity may be superior at promoting cardiorespiratory fitness. Because of this, the authors of this study hypothesized that high intensity exercise might provide benefits that moderate activities could not. More specifically, the aim of their study was to investigate whether higher proportions of vigorous activity would be associated with a lower risk of all-cause mortality.
The results indicated that independent of the total time spent engaging in physical activity, a portion of that time being spent doing vigorous activity was protective against all-cause mortality. This finding was consistent amongst multiple subgroups, including men and women, various age groups, and those with or without previous cardiovascular disease or diabetes. While this study is observational, based on self-reported data, and only addresses geographically restricted populations in New South Wales, its findings suggest that encouraging vigorous activity may provide benefits to health and wellness.
In-Depth [prospective cohort]: Data was obtained as part of the Sax Institute’s 45 and Up Study cohort, sampling from the general population of New South Wales, Australia. Baseline data were collected between 2006 and 2009, and follow-up continued until 2014. Exclusion criteria included age above 75 years, or incomplete data for physical activity. A total of 204,542 participants were ultimately included in analysis. With respect to assessment of physical activity, the Active Australia Survey was used, which has been previously validated. This asks participants about periods of time 10 minutes or longer, of walking, moderate, and vigorous activity in the previous week. The proportion of moderate to vigorous physical activity (MVPA) was calculated. Covariables studied included age, sex, educational level, marital status, urban or rural residence, BMI, smoking or alcohol use, and fruit and vegetable consumption.
During 444,927 person-years of follow-up, there were 7435 deaths. Compared with those who reported no MVPA (crude death rate, 8.34%), the adjusted hazard ratios for all-cause mortality were 0.66 (95% CI, 0.61-0.71) for reporting 10-149 minutes a week of activity, 0.53 (95% CI, 0.48-0.57) for those who did 150-299 minutes/week of activity, and 0.46 (95% CI, 0.43-0.49) for reporting more than 300 minutes/week. The hazard ratio was 0.91 (95% CI, 0.84-0.98) in those who reported some vigorous activity (but <30% of total activity) and 0.87 (95% CI, 0.81-0.93) among those who reported 30% or more of activity as vigorous. These results were not affected by gender, BMI, and presence or absence of cardiovascular disease or diabetes.
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