General inclusion criteria included being over 55 years of age and normotensive (e.g., <140/90 mm Hg). Specifically for this group, we include participants engaging in swimming or other aquatic, primarily aerobic-based, training regimes for more than 2 times a week, for more than 6 months, at the time of the assessments.

General inclusion criteria included being over 55 years of age and normotensive (e.g., <140/90 mm Hg). Specifically for this group, we include participants engaging in land-based, primarily aerobic training regimes (e.g. aerobic exercise) for more than 2 times a week, for a period longer than 6 months, at the time of the assessments.

General inclusion criteria included being over 55 years of age and normotensive (e.g., <140/90 mm Hg). Specifically for this group, we include participants engaging in both land-based and aquatic, primarily aerobic, exercise regimes on an equal basis, for more than 6 months.

General inclusion criteria included being over 55 years of age and normotensive (e.g., <140/90 mm Hg). Specifically for this group, we include participants who are sedentary (e.g., defined as undertaking less than 60 min of structured/planned physical activity per week), for a period longer than 6 months.

Participants belonging to Group D (sedentary group) will be randomised 1-to-1 between remaining sedentary (n=20) and following a self-managed, 8-week, aquatic-based exercise programme (n=20). The latter group will be offered an 8-week access to pool facilities. For Group D participants, all baseline assessments will be repeated at 8 weeks.

We will use FMD as a measure of endothelium-dependent, nitric oxide (NO)-mediated, macro (arterial)- circulatory function. Baseline scanning to assess resting vessel diameter will be recorded over 3 minutes, following a 10-minute resting period. A rapid inflation-deflation pneumatic cuff placed immediately distal to the elbow joint will be used to as an FMD stimulus.

We will use FMD as a measure of endothelium-dependent, nitric oxide (NO)-mediated, macro (arterial)- circulatory function. Baseline scanning to assess resting vessel diameter will be recorded over 3 minutes, following a 10-minute resting period. A rapid inflation-deflation pneumatic cuff placed immediately distal to the elbow joint will be used to as an FMD stimulus.

Skin blood flow will be measured as cutaneous red blood cell flux using a Laser Doppler Flowmeter (LDF). Local thermal hyperaemia will be induced using a heating disc surrounding the probe. The probe will be attached to the skin using a double-sided adhesion sticker. Participants will be rested in a supine position in a temperature-controlled room with a constant ambient temperature of 24° C for 35 minutes. Heart rate and diastolic and systolic blood pressure was recorded from the left arm at 5-minute intervals throughout the protocol (Dinamap Dash 2500, GE Healthcare, USA). Baseline skin blood flow data will be recorded for 5 minutes with the local heating disc temperature set at 30° C. Following this, rapid local heating will be initiated to obtain maximal vasodilation and the temperature will be increased by 1° C every 10 seconds until 42° C was reached. This will then be maintained for 30 minutes following, which the test will be completed.