High-intensity Interval Training Combined with Muscle-strength Training in Older Women

Inclusion Criteria: * Females (biologically at birth) * At least 60 years of age at the time of signing the informed consent * Non-smoker, including electronic cigarettes * Not participating in routine high-intensity aerobic or muscle strength exercise training (≥ 75 min/week of structured vigorous aerobic exercise, or 2 times /week of structured muscle strength training) * Able to perform a cardiopulmonary exercise testing (CPET) to exhaustion * willing to complete baseline and follow-up measures, and attend prescribed exercise sessions at the University of Nottingham * willing and able to give informed consent for participation in the study Exclusion Criteria: * Diagnosed with cardiovascular disease, kidney disease, diabetes, obstructive pulmonary disease, or uncontrolled hypertension * History or current neurological or psychiatric illness, or motor or cognitive restrictions * Contraindications to symptom-limited cardiopulmonary exercise testing (CPET), including resting hypertension with systolic blood pressure \>200 mmHg or diastolic blood pressure \> 110 mmHg, uncorrected medical conditions, such as significant anemia, important electrolyte imbalance, and hyperthyroidism, mental impairment with limited ability to cooperate, physical disability that precludes safe and adequate testing. * Having taken part in a research study in the last 3 months involving invasive procedures or an inconvenience allowance.