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  • Higher Proportion of Vigorous Physical Activity Lowers Mortality Risk

    A new study from Australia concludes that while achieving at least the minimum amount of recommended weekly physical activity is key to a lower mortality risk, upping the amount of vigorous physical activity in an individual's exercise mix can reduce that risk even further.

    In an 8-year observational study of 204,542 New South Wales adults aged 45 to 75, researchers paired mortality statistics with percentages of moderate to vigorous activity (MVPA) to find out whether the proportion of vigorous activity had an impact on mortality risk.

    The answer: yes, by as much as 13%. The study was published in the April 6 online edition of JAMA Internal Medicine (abstract only available for free).

    Using recommendations that individuals engage in at least 150 minutes per week of moderate physical activity or 75 minutes per week of vigorous activity, authors found that the crude death rate for individuals who met the recommendations but engaged in no vigorous activity was 3.84%, compared with a 2.35% crude death rate for individuals who engaged in "some" vigorous activity (but no more than 30% of total activity), and a 2.08% crude death rate for those who reported that 30% or more of their activity time was devoted to vigorous exercise.

    The questionnaire used to obtain the activity self-reports defined vigorous activity as an activity "that made you breathe harder and puff and pant, like jogging, cycling, aerobics, competitive tennis, but not household chores or gardening." Examples of moderate physical activity used in the questionnaire included "gentle swimming, social tennis, vigorous gardening, or work around the house."

    "In this large sample of middle-aged and older adults, we found that among those who reported any physical activity, engaging in vigorous activity was associated with risk reductions for mortality of 9% to 13%, even after adjusting for the total amount of activity," authors write. "These findings suggest that even small amounts of vigorous activity may supplement the benefits of moderate activity alone."

    Researchers write that more work needs to be done to find out exactly why vigorous activity has this effect, but they suggest the possibility that "high-intensity activities lead to more physiologic adaptations, which improve function and capacity." Those improvements enhance the delivery of oxygen and glucose to tissues.

    While the relationship between vigorous activity and mortality risk was measurable, the biggest drop in crude death rate appeared after much lower amounts (and intensities) of physical activity were reported—from a crude death rate of 8.34% who reported no MVPA, the rate dropped to 3.17% for individuals reporting 10 to 149 minutes of MVPA. Similar significant improvements were recently reported in another study that focused more widely on physical activity's effect on mortality, and whether there was an upper limit to these effects.

    Authors of the Australian study write that even more benefit can be achieved when the proportion of vigorous activity is increased—provided there are no other risks present.

    "Independent of the total amount of physical activity, engaging in some form of vigorous activity was protective against all-cause mortality," authors write. "If vigorous activities are consistently independently associated with health benefits, such activities should be more strongly encouraged in activity guidelines to maximize the population benefits of physical activity."

    Did you know that there's a national blueprint for increasing physical activity among adults 50 and older? Learn how the blueprint could guide your efforts by taking a CE course offered through the APTA Learning Center.

    Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.  

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