PhD Scholarship - Patterns of objectively measured physical activity and healthy ageing: Does one-size-fit-all? (UQ/Exeter Joint PhD)

Population ageing is associated with increased economic and societal burden, due to multiple morbidities and loss of function. Physical activity (PA) is arguably the most important modifiable preventive factor associated with healthier ageing, especially if optimal patterns of PA are established in late-middle to early older age (referred to here as the ’young-old’ life-stage).

Public health guidelines for physical activity encourage adults to accumulate at least 150-minutes per week of moderate-vigorous intensity PA. However, this ‘one-size-fits-all’ recommendation may be less appropriate for young-old adults. Recent studies utilising objective measures of PA (accelerometers) have suggested that, at this life-stage, lower volumes of PA confer significant health benefits. Such studies have only focused on a few simple metrics that summarise the time spent in PA at different activity intensities. These metrics were based on calibration studies undertaken in young healthy populations and therefore are likely to misclassify levels of PA in older people.

The paucity of studies that precisely measure physical activity in young-old adults means that true associations between PA and healthy ageing are likely to be underestimated, and our understanding of the ‘optimal’ PA pattern for successful ageing is poorly understood.

The development of novel metrics that better reflect levels and patterns of PA at this life-stage would provide a better understanding of how physical activity patterns are related to specific health outcomes, which in turn could lead to more appropriate and targeted prevention interventions. This project will use systematic reviews, meta-analyses and new analyses of data from large population-based cohort studies in Australia and the UK that have measured physical activity using raw accelerometry in over 100,000 ’young-old’ adults, to investigate whether different patterns of PA are associated with different health outcomes.

The specific aims of this project are to:

- identify patterns of objectively-measured physical activity (assessed with wrist-worn accelerometers) and to develop novel metrics for assessing the relationships between PA and health outcomes in ’young-old’ adults;
- investigate the socioeconomic, demographic, social and environmental (neighbourhood) determinants of specific patterns of objectively measured physical activity in ’young-old’ adults;
- improve understanding of inequalities in physical activity at this life-stage.