Microvascular Coronary Rehabilitation For Improving Treatment - Feasibility Study

The goal of this clinical trial is to assess the feasibility of undertaking a randomized controlled trial assessing the impact of a personalised, intense cardiac rehabilitation programme involving high intensity interval exercise (HIIT) and dietary advice (termed MICROFIT) on symptom burden in patients with microvascular coronary dysfunction. The main questions it aims to answer are: 1. Feasibility of undertaking randomised controlled trial of MICROFIT in patients with coronary microvascular dysfunction (recruitment rates, retention and adherence, acceptability of MICROFIT and participants' and practitioners' experiences of trial participation) 2. Preliminary data on the effect that MICROFIT has on angina symptoms in patients with microvascular coronary dysfunction, as measured by Seattle Angina Questionnaire 3. Preliminary data on the fidelity and clinical efficacy of MICROFIT Participants will be randomized to either MICROFIT + Usual Care, or Usual Care group. Participants in both arms of the trial will: * Undergo a series of investigations, including cardiopulmonary exercise test (CPET), dual xray absorptiometry (DEXA), echocardiogram, cardiac MRI scan, blood tests, at the start of the trial and again after 6 months * Measure their living activity by using an activity tracker (GeneActiv) as well as a photographic diet diary for a week at the start of the trial and again after 6 months * Complete a series of questionnaires to assess angina symptom burden, mental health and quality of life, at the start of the trial and again after 6 months. Participants in the intervention arm of the study will: 1. Undergo MICROFIT intervention. MICROFIT includes a combination of exercise and diet management sessions over 24 weeks. It involves: * 1:1 high-intensity interval training ('HIIT') sessions with a personal trainer and guidance on exercise sessions to be performed at home * 1:1 sessions with a dietician to support them with improvements in diet. 2. Visit cli