The effects of isometric exercise training and detraining on cardiovascular adaptation, with special reference to resting blood pressure

Isometric wall squat (IWS) training is now well established as an effective exercise training intervention for the reduction of resting blood pressure (BP). However, there remains limited research to support its widespread adoption and acknowledgement within healthcare guidelines. As a result, this thesis set out to investigate some key areas that were identified as gaps in the current literature to progress the clinical utility of IWS training. Study 1 explored the BP reductions and associated physiological mechanisms following 4 weeks of IWS training using a large sample size. The study also attempted to identify whether there were sex-based differences in any BP reductions observed. It was found that IWS training is effective at reducing resting BP in both males and females, and that the observed BP reductions were likely driven by decreases in total peripheral resistance and adaptations to cardiac autonomic function rather than centrally mediated changes in cardiac output. Study 2 then compared the BP reductions and cardiovascular adaptation between 4 and 8 weeks of IWS training period to ascertain the influence of training duration on resting BP reductions. The study found that extending IWS training to 8 weeks resulted in significantly greater sBP reductions (but not dBP or MAP), though the rate of reduction plateaued after 4 weeks. Study 3 then investigated the effects of detraining on resting BP reductions following the cessation of IWS training. Results from this study indicate that a complete cessation of IWS training results in a reversal of both resting BP reductions and all associated cardiovascular adaptations. Lastly, Study 4 sought to identify the minimum frequency of IWS sessions required to maintain resting BP reductions during a follow-up training period. It was demonstrated that significant reductions in resting sBP and MAP can be maintained with just one training session per week, although greater overall cardiovascular benefits can be achieved with three sessions per week. Collectively, the findings from this thesis have provided further evidence for the effectiveness of IWS training in reducing resting BP. The findings also elucidate the cardiovascular mechanisms involved in any BP reductions and offer practical guidelines for the maintenance of BP reductions with implications for improving the adherence and long-term efficacy of IWS training.