The association between physical activity and vascular health in a cross section of older adults : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University

Abstract

In New Zealand, the older adult population is the fastest growing age group, currently with 29,000 90 plus year olds, and it is projected to surpass 180,000 by 2060 (Stats NZ, 2019b). Older age is associated with frailty along with other health conditions such as heart disease, stroke, diabetes, arthritis and chronic pain (Ministry of Health [MOH], 2016b). Cardiovascular disease is the largest preventable cause of death in New Zealand, equating to 33% of the nation’s deaths annually (MOH 2019a; Heart Foundation, 2020a). Cardiovascular disease includes heart, stroke and blood vessel disease, including hypertension (Heart Foundation, 2020b). This cross-sectional study investigated the association between physical activity measured in MET minutes (MET-mins) and arterial stiffness using Pulse Wave Velocity (PWV). These two variables were then assessed for their association with health parameters including balance, aerobic capacity, quality of life (QOL), systolic blood pressure, hand-grip strength and leg strength in older adults living independently in retirement villages. Pearson correlations indicated that four control variables (covariates) and three predictor variables were correlated to PWV: age (r=.50, p<.01), previously having a stroke (r=.33, p <.05), heart incident (r=.31, p <.05), healthy diet (r=-0.23, p <.05), brachial systolic blood pressure (r=.50, p<.001), leg strength (r=-.23, p<.05) and aerobic capacity (r=-.19, p<.05). In addition, MET-mins were correlated to age (r=-.46, p<.001.), stroke incident (r=-.27, p<0.01), balance (r=-0.32, p<.05), aerobic capacity (r=0.24, p<.05), and lower brachial systolic blood pressure (r=-.22, p<.01). Four QOL variables were correlated to MET-mins: physical functioning (r=.34, p<.0001), general health (r=.29, p<.005), role limitations due to emotional problems (r=.28, p<.006), and limitations due to physical health (r=.24, p<.022). Three QOL variables were correlated with PWV: limitations due to physical health, (r=-.27, p<.015), limitations due to emotional health (r=-.24, p<.027), and physical functioning (r=-.22, p<.05). When analysed as multiple hierarchical regression, age significantly predicted PWV, along with heart incident and stroke when all four covariates were used in Model 1. There was a negative correlation between PWV and METs (r=-.31, p<.05), a medium effect size, with a lower PWV score, correlated with a higher score of total METs for participants. PWV mean was 11.9 ± 2.4 and the participants’ mean METs minutes per week were 4557.8 ± 2836.22 resulting in 99% of this population meeting or exceeding guidelines as recommended by the Physical Activity Guidelines Advisory Committee (2018), the World Health Organization (WHO, 2011) and the New Zealand Older Adults Guidelines (MOH, 2013). As the population gets older in New Zealand (and globally), it is important to have an understanding of preventative healthcare. Then the ageing population is ensured that their longer life expectancy can be lived to the fullest without those increased years being affected by ill health (MOH, 2011). However, an important suggestion could be to ensure retirement villages are giving their residents every opportunity available to be active and stay active in their ageing years.