Physical activity and health in mid-age and older Australian women
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Discussion
It is clear that there is a need for more research into the dose-response issues relating to physical activity and health to clarify the individual contributions of intensity, frequency, duration of physical activity to different health outcomes. Several groups of US researchers are now conducting randomised controlled trials which are exploring the effect of different combinations of duration, frequency and intensity on health outcomes in women (eg Morss, Jordan, Skinner et al., 2004; Dunn, Trivedi, & O'Neal, 2001). A major challenge with these studies is to find representative samples of women who will comply with the different physical activity protocols for long enough for the health outcomes to be explored.
What is absolutely clear from this review is that the so called Rose principle of improving population health holds true in terms of physical activity and health (Rose, 1992). If a large segment of population could be persuaded to adopt modest improvements in physical activity – even 15-30 minutes per day, every day – the overall reduction in disease burden would be greater than if a modest segment adopted larger changes. It is also clear from the evidence reviewed here that getting women who are currently sedentary to 'take' a small daily dose of physical activity would result in much greater health outcomes than getting those who are already active to double their dose of physical activity.
In light of the health benefits of being more active in mid-age, public health policy should now focus on getting the most sedentary women to become more active. Even 15 minutes of daily moderate intensity activity is associated with some health benefits. Mid-age and older women who are already meeting activity guidelines should be encouraged to maintain this level of activity for as long as possible as they age. The magnitude of this challenge is outlined using data from the ALSWH in the next section of this report.