The effect of combined exercise training on exercise intolerance and cardiovascular health outcomes in adults living with atrial fibrillation.

INTERVENTION: Combined exercise training (CT): For participants randomised to the CT group, exercise training will be completed 3 days per week for 12 weeks (36 sessions), with 2 sessions per week to be completed as group sessions (no more than 4‐5 participants per group) face‐to‐face supervised sessions with an Accredited Exercise Physiologist in the Institute for Physical Activity and Nutrition's (IPAN) exercise lab and gym and 1 session to be performed as an individual unsupervised session at home. The 2 face‐to‐face supervised sessions per week will incorporate both aerobic and resistance training components and the 1 unsupervised session per week will be aerobic training only. Session 18 will involve supervised retesting of cardiorespiratory fitness and muscular strength to modify individual exercise prescriptions due to any changes in fitness levels. All supervised exercise sessions will take 45‐60 mins, with all unsupervised MIIT sessions taking 20‐30 mins in duration. Moderate‐intensity interval training (aerobic training): For the aerobic training component, participants will complete moderate intensity‐interval training (MIIT), with a 3 minute warm‐up and cool‐down to be performed at each session at a light‐ to moderate‐intensity (45‐50% HRR, or Borg’s Rating of Perceived Exertion [RPE] of 10‐11/20) prior to and immediately following MIIT, respectively. This will involve a gradual increase in intensity during the warm‐up and a gradual reduction in intensity during the cool‐down to avoid vasovagal events or syncope This will be completed on an aerobic exercise mode of the participant’s choice (e.g. walking, cycling, aerobic stepping, rowing etc.) during supervised and unsupervised sessions. Sessions 1‐5: 4x4 minute moderate‐intensity intervals (70‐75% heart rate rese CONDITION: atrial fibrillation;exercise intolerance;impaired microvascular blood flow; ; atrial fibrillation ; exercise intolerance ; impaired microvascular blood flow Cardiovascular ‐ Diseases of the vasculature and circulation including the lymphatic system Cardiovascular ‐ Other cardiovascular diseases PRIMARY OUTCOME: Change in skeletal muscle microvascular blood flow as assessed by contrast‐enhanced ultrasound. [Baseline repeated measures (pre‐exercise, immediately following exercise, 60‐mins post‐exercise) and 12‐weeks post‐intervention (>48 hours after the last exercise session) repeated measures (pre‐exercise, immediately following exercise, 60‐mins post‐exercise). ] Changes in exercise tolerance as assessed by peak volume of oxygen uptake (VO2 peak ).[Baseline, 6 weeks and 12 weeks post‐intervention (>48 hours after the last exercise session).] INCLUSION CRITERIA: INCLUSION CRITERIA: (i) clinical diagnosis of atrial fibrillation as confirmed by a physician with supporting electrocardiogram; (ii) physically inactive (<150 mins exercise per week); (iii) 40‐80 years old. SECONDARY OUTCOME: C‐reactive protein as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention] Changes in arterial stiffness as assessed by applanation tonometry. [Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session).] Changes in atrial fibrillation symptom severity as assessed by the Atrial Fibrillation Symptom Severity Scale (AFSS) Questionnaire. [Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session). ] Changes in body composition as assessed by dual‐energy x‐ray absorptiometry (DXA)[Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session).] Changes in cardiac function as assessed by cardiac ultrasound.[Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session). ] Changes in femoral artery blood flow as assessed by ultrasound recording and imaging. [Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session). ] Changes in lower body body muscular strength as assessed by one repetition maximum testing of the leg press[Baseline, 6‐weeks and 12 weeks post‐intervention (>48 hours after the last exercise session).] Changes in Physical Activity Levels as assessed using an accelerometer (ActiGraph wGT3X‐BT). [Baseline and 12‐ weeks post‐intervention (>48 hours after the last exercise session). ] Changes in quality of life as assessed by the Atrial Fibrillation Effect on Quality of Life (AFEQT) Questionnaire.[Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session). ] Changes in Sedentary Levels as assessed using an accelerometer (ActiGraph wGT3X‐BT). [Baseline and 12 weeks post‐intervention (>48 hours after the last exercise session).] Changes in upper body muscular strength as assessed by one repetition maximum testing of the chest press. [Baseline, 6 weeks and 12 weeks post‐intervention (>48 hours after the last exercise session).] Fasting blood glucose as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention] Glycosylated haemoglobin as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention] HDL‐C as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention] LDL‐C as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention] Total cholesterol as assessed by venous blood sampling. [Baseline and 12 weeks post‐intervention]