Exploring time-efficient strategies to improve fitness in older adults

Background Exercise interventions have the potential to reverse some of the health deficits associated with aging and improve the fitness of older adults, however rates of exercise uptake and adherence are strikingly low with “lack of time” a commonly cited reason. Methods This thesis carried out a systematic review of all non-pharmacological interventions to address one of these deficits (blood pressure), before describing a randomised controlled trial of three, time-efficient physical activity interventions: high-intensity interval training (HIIT), isometric handgrip (IHG) training and remote ischaemic preconditioning (RIPC) with the primary outcome of reducing resting systolic blood pressure. Results Meta-analysis demonstrated that physical activity interventions such as aerobic or resistance exercise can lead to significant reductions in resting blood pressure, however the majority of interventions require a minimum of 3 months. The randomised controlled trial described in this thesis showed that 6 weeks of either HIIT or IHG can reduce resting systolic blood pressure by 9 mmHg, with HIIT also increasing anaerobic threshold (a marker of cardiorespiratory fitness) by 2ml/kg/min. Conclusions Six weeks of either the HIIT or IHG protocols described in this thesis can lead to both statistically significant and clinically relevant reductions in resting systolic blood pressure in healthy older adults in 6 weeks, with HIIT having additional benefits on markers of cardiorespiratory fitness. These protocols have the potential for use as physical activity interventions in older adults to improve various markers of health