Inclusion Criteria:  Men and women, UK based, above 21 years of age and below 65 years of age All participants: No known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire) All participants: Not currently suffering from any musculo-skeletal injury, or any other reason that may prevent participation in cardiovascular exercise All participants: Have not suffered from recent viral infections ie: influenza (defined within the prior 2 months) All participants (and household members): COVID-19 related - have not suffered with any symptoms associated with Covid-19 All participants: Not suffering from any known blood related disorders, including blood coagulation abnormalities, or have any adverse reactions to blood taking All participants: Not taking any prescribed or over-the-counter medication which may influence exercise training (with the exception of inhalers for exercise induced asthma or contraceptive pill) All participants: Not consuming or prepared to refrain from consumption, any commercial supplementation which conflicts with the study parameters ie: antioxidants. All participants: no known allergy or intolerance to olives or prune/grape juice. Baseline maximal oxygen uptake >25ml/kg/min representative of normal fitness levels (measured during pre-screening)  Exclusion Criteria:  Anyone below the age of 21 years or above 65 years of age All participants: anyone with a known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire) All participants: Anyone suffering from a current musculo-skeletal injury, or any other reason that may prevent participation in cardiovascular exercise All participants: those suffering from recent viral infections ie: influenza (defined within the prior 2 months) All participants: anyone who has (previously or currently) had any symptoms associated with covid-19 (including household members) All participants: Those with known blood related disorders, including blood coagulation abnormalities, or have any adverse reactions to blood taking. This includes any participant who has or potentially has an infectious disease, inc. HIV, and all types of hepatitis. All participants: Anyone taking any prescribed or over-the-counter medication which may influence exercise training (with the exception of inhalers for exercise induced asthma or contraceptive pill) All participants: Anyone consuming or not prepared to refrain from consumption, any commercial supplementation which conflicts with the study parameters ie: antioxidants All participants: anyone with a known allergy or intolerance to olives or prune/grape juice. Any not meeting the baseline criteria for maximal oxygen uptake FEMALE ONLY: Any participant who is, suspects they may be or becomes pregnant during the study.