The Effects of Exercise on Vascular Physiology in Systemic Sclerosis Patients

The original research in this thesis aimed to investigate the efficacy and feasibility of exercise in people with systemic sclerosis (SSc). The heralding symptom in the pathophysiology of SSc is vascular dysfunction in the digital area which is the primary cause of Raynaud's phenomenon (RP). Digital disfiguration, ulcers and RP affect the quality of life (QoL) in people with SSc. Medical treatment does not have dramatic improvements and is also accompanied by short- and long-term side effects leading to further health complications. Exercise could be considered as a safe and cost-effective adjunct therapy that could potentially reduce the use of medication. The primary outcomes in study 1 were the physiological differences between the arm crank (ACE) and cycler ergometer (CE) protocols in sedentary adults. Study 2 investigated the microvascular function, quality of life, cardiorespiratory fitness, functional capacity and body composition in people with SSc. Study 3 explored the feasibility of exercise in people with SSc with primary outcomes being the recruitment and attrition rates as well as the adherence rates to exercise. The novel findings of this research were: Study's 1 novelty was 1) the predictive equation for the cycle ergometer peak oxygen uptake (CEV̇ O2peak) trough the physiological responses of ACE and body composition features (Study 1). The equation estimated with this model is: CEV̇ O2peak = 11.776 + 1.418 X arm crank ergometer peak oxygen uptake (ACEV̇ O2peak) (ml·kg-1·min-) – 1.454 x total lean body mass (TLBM) + 3.967 X lower limb lean body mass (LLLBM). This predictive equation was later used in study 2 to compare ACE to CE V̇ O2peak as a correlation between the improvement of microcirculation (laser-Doppler fluximetry) and V̇ O2peak has been demonstrated in rheumatoid arthritis patients before (Metsios et al., 2014). Study's 2 novelties were 2) ACE seems more potent to improve the microcirculation in the digital area in people with SSc compared to CE, 3) the exercise programme that consisted of a high intensity interval training (HIIT) protocol that was performed for 12 weeks twice per week seems capable to prevent the formation of digital ulcers in people with SSc and the concomitant hospitalisations and/or in some occasions digital amputations, 4) QoL in people with SSc significantly improved after the exercise intervention. Study's 3 novelties were that 5) the exercise programme (12 weeks, twice/week) was feasible in people with SSc with very high recruitment and adherence rates, 6) our combined exercise protocol (HIIT and resistance training) was enjoyable and fairly easy to be performed by our participants, 7) individuals experiences confirmed the feasibility of our intervention and exercise protocol and highlighting the importance of applying supervised exercise programmes. Study 2 acted as a guiding study as to which mode of exercise could induce better results in the microcirculation in the digital area. Afterwards, study 3 utilised the upper limb exercise with weight training to assess its feasibility in people with systemic sclerosis. These findings contribute to the growing evidence base for the effects of exercise in people with SSc. Our study is the first to investigate the effects of HIIT on digital microcirculation in people with SSc and the first to explore the feasibility of a combined exercise protocol in this clinical population. Future research should explore the effects of exercise in people with SSc in larger clinical trials.