The findings from DYNOPTA data confirm the low physical activity prevalences among older Australians. These physical activity prevalences closely reflect the age and sex trends reported in national survey data, but the DYNOPTA data shed light on the duration of activity among those who were active.
Physical activity prevalence
The prevalence of physical activity behaviour in those aged 65 years and over was greater in men than in women. Time spent walking decreased with age in men; women reported less walking time than men across all age groups. A similar pattern was observed for moderate and vigorous activity. The DYNOPTA data enabled us to explore in detail patterns across the ‘old old’ (those aged 75 years and over). The greater detail about the ‘old old’ afforded by the data showed that men walk less as they get older and the decline in walking activity is most noticeable in the over 80s. Moderate activity behaviour declined with age, but the decline was most pronounced in the oldest women. A similar pattern was observed for vigorous activity, although a small number of the ‘old old’, particularly men, were still active at these intensity levels.
One reason for the decline in physical activity, even walking, could be an age-associated decline in physical mobility. Wave 1 harmonised data from the complete DYNOPTA population highlighted a marked decline in the ability to walk various distances (e.g. 1 km, 500 m, 100 m), to mobilise within the home, and to transfer . For example, while most people in their 70s (80% women and 83% men) were able to walk 1 km (with or without some difficulty), as these people aged the distance that could be walked decreased. The proportions who were more seriously disabled in mobilising and transferring also increased.
The prevalence of physical activity was greater in DYNOPTA than in the NHS dataset across age and sex groups. This finding indicates that older people may be more physically active than the national data suggest. As DYNOPTA is representative of the population, this larger sample of older people offers a more encouraging picture of the physical activity behaviour of older people.
However, looking at the findings in greater detail highlights that there is much scope for increasing levels of physical activity. For example, the youngest DYNOPTA women reported less time spent walking than their NHS counterparts. Targeting this age group to promote incidental activity such as walking has the potential to increase physical activity behaviour as they enter their 70s and 80s. While the women in their 70s and beyond reported more moderate activity than their NHS counterparts, the proportion who did any moderate activity was much lower than for the men. There is potential to encourage more moderate activities in these women. The DYNOPTA data show that some vigorous activity does occur in both men and women across the age groups, possibly as people continue the activities they have done throughout their adulthood.
The findings were not adjusted for health status. An explanation of the differences could be that the DYNOPTA sample is a healthier sample than the older adults in the NHS. Previous comparison of the disease prevalence among 12 000 of the DYNOPTA dataset for 2000–2002 with the 2001 NHS data indicated that this is not necessarily the case. While diabetes prevalence was lower, asthma and hypertension rates were higher in DYNOPTA than the NHS . Analyses of depression prevalence  and dementia prevalence  in DYNOPTA do not suggest a healthy cohort effect. Bartsch and colleagues  recently reported that Short Form (SF-36) scores in DYNOPTA were similar to those in the 1995 NHS. It is difficult to make direct comparisons given the nationally used age bands may hide any variations in health.
Evidence-based physical activity recommendations specifically for older Australians have been introduced since these data were collected . Their aim is to motivate older people to adopt and maintain a range of forms of physical activity in accordance with their capacity, goals and preferences. The recommendation concerning frequency and duration is in line with the original adult guidelines: at least 30 minutes of moderate-intensity activity on most days of the week. Comparing the prevalence rates reported here to this recommendation, we can see that there remains considerable scope to increase the proportion of older people who are physically active. Armstrong and colleagues  assessed the impact of recent physical activity campaigns on intention to be active. Older people were less likely than younger ones to intend to become active: 56.5% did not intend to become active, only 22.5% intended doing so in the next month and 20.9% in the next 6 months. However, older people were more likely to recall a generic physical activity campaign (around 60%) (Active Australia) and about 24% recalled a more specific campaign for older people . This indicates that media campaigns may be a particularly effective means to promote physical activity in older people. As the physical activity recommendations for older people remain to be widely disseminated, there is the opportunity to assess their impact on physical activity in the coming years. However, it is recognised that recommendations alone do not change behaviour. The evidence emphasises the need for multifaceted approaches, including supportive physical and social environments for activity and attention to individual motivators for behaviour change, to promote and support physical activity among older people [23, 24]. Australia benefits from the presence of a broad range of programs tailored for older people, such as the COTA Australia ‘Living Longer, Living Stronger’ program . The challenge remains to extend the reach of these programs across older people.
Use of the pooled dataset has some limitations. Not every study contributed every physical activity variable data to the harmonised dataset. As not all contributing datasets were nationally representative, the sample needed to be weighted to produce population estimates. The physical activity data were obtained by self-report; while this is accepted method, particularly in large-scale studies, it can create reporting bias. There was variability between studies in the sampling methods used, the inclusion and exclusion criteria, and modes of survey administration and this potential for heterogeneity had to be tested and adjusted for. The largest proportion of the sample examined in this paper was of older women in their seventies. This and the large proportion that performed no activity created skewed data and raises queries about the representativeness of the data from those who were active. It was not possible to analyse the activity patterns of the ‘oldest old’ (85+ years) because of their relatively small numbers in the current dataset.
A strength of the harmonised data was the reference to a 1-week recall period for physical activity. The NHS refer to the past fortnight. Although the NHS results were divided by two to produce a weekly value, the activity may not have been evenly spread across the 2 weeks. Bursts of activity, where 1 week is spent in sedentary behaviour and the next in exercise may not impart the same protective health benefits as more regular activity. The physical activity patterns of over 10 thousand people could be examined using the DYNOPTA data. Crucially, the DYNOPTA data enabled detailed exploration of the physical activity patterns of those aged 75 years and over.