The effects of aquatic high-intensity interval training on cardio-metabolic health, cognition and perceptual responses in physically inactive aged women

Abstract

This thesis begins with a meta-analysis (Study 1) of previously-published studies of aquatic high-intensity interval training and its effects on cardiac, metabolic and physical health markers in aged women. The review included thirteen research studies. Given the high prevalence of physical inactivity, obesity and osteoarthritis among aged women, that was the population chosen as a target group. The aim of this study was to investigate the effects of aquatic high-intensity interval training on cardiac-metabolic and physical outcomes. It suggested that aquatic high-intensity interval training has a moderate effect in improving these health markers in such women group. This provided the background for a further review of the effects of deep water running as a modality in improving the cardiorespiratory fitness, physical functioning and quality of life of adults. Study 2 was a systematic review which identified eleven clinical trials of the effectiveness of deep water running. Improvements in adults’ cardiorespiratory fitness, physical functioning and quality of life were compared through land exercises or without any dedicated exercise. The findings suggested that deep water running may offer results comparable to those of land-based training, though with mixed results when compared with taking no dedicated exercise. That motivated the next step of developing an effective intervention program to improve cardiac and metabolic outcomes based on deep water running. A reliable, valid and water resisted tool that accurately assesses patients’ progress would be very helpful. Study 3 was designed to quantify the validity and reliability of using an inexpensive 3D-printed portable metabolic analyser PNOĒ to measure the cardio-metabolic outcomes of aquatic exercise in terms of aerobic fitness. Two cross-sectional pilot studies were performed to develop an aquatic high-intensity interval training protocol in Study 4. The first study varied the cadence to establish a matched intensity between aquatic and land-based high-intensity interval training through comparing the cardio-metabolic and perceptual responses. Results indicated that aquatic exercise produced a greater reduction in heart rate and a greater increase in oxygen pulse. The second pilot study explored the benefits of increasing the intensity of the aquatic exercise by adding resistance. The resistance was found to produce no significant change in heart rate or peak oxygen uptake, but it did tend to increase the perceived rate of exertion. A randomized and controlled trial (Study 5) was organized which compared the effects of an 8-week program of aquatic high-intensity interval training based on running in deep water with those of a matched program administered on land. Cardio-metabolic, cognitive and psychological outcomes were compared. The deep-water running program was found to improve oxygen capacity, metabolic equivalents, blood oxygen and ventilation as well as the land-based exercise program. It also produced in this population similar improvements in cognition as assessed by the Mini-Mental Status Examination and the Montreal Cognitive Assessment. These findings suggest high-intensity aquatic exercise could serve as an alternative to add value to land-based alternatives. It should be considered by healthcare professionals when designing programs targeting specific cardio-metabolic health benefits, metabolic blood markers, cognitive functioning, and perception in physically inactive older women.