Exercise and Sauna on Blood Pressure and Cardiovascular Health (ES2019)

The study aims to investigate the effects of including regular heat therapy when included to exercise. Specifically, participants in the sauna intervention group will undergo 15 minutes of sauna exposure immediately after a 50-minute session of exercise, 3 times a week, while participants in the exercise intervention group will follow only the same exercise protocol. The 50-minute exercise session consists of 20 minutes of moderate intensity strength exercise, followed by 30 minutes of moderate-vigorous aerobic exercise on stationary bikes. This exercise intervention protocol was selected in order to meet and adhere to the recommended physical activity guidelines.

The main purpose of the experiment is to investigate the cardiovascular modulations of sauna use with respect to vascular compliance and hemodynamics. The investigators seek to understand the long-term adaptations of regular sauna bathing in conjunction with exercise, particularly in sedentary populations with cardiovascular risk factors. Of particular interests are the cardiovascular adaptations of regular sauna bathing when used in conjunction with exercise training; which meets the recommended minimum of current physical activity guidelines. Recent studies have shown that long-term sauna use with exercise is more effective than sauna use alone in patients with chronic heart failure. However several questions pertaining to regular exercise in combination with sauna use remain to be answered, as experimental data in the general population is still lacking. This research project aims to find out the differences (if any) in cardiovascular and hemodynamic-related outcome parameters, between regular exercise according to the minimum recommended guidelines, and the same exercise program with an additional regular 15 minute sauna session post exercise. The training intervention will last for 8 weeks, with each session consisting of 20 minutes of moderate intensity resistance training, followed by 30 minutes of aerobic training. Participants in the exercise only group rested in the training area for 15 minutes while the exercise and sauna participants went to the sauna for 15 minutes. Temperature of the sauna room was increased by 5 degrees celsius every fortnight starting from 65 degrees celsius; during the final 2 weeks of the intervention the sauna temperature was at 80 degrees celsius. (65, 70, 75, 80). Participants were told that they could leave the sauna room anytime they felt uncomfortable or if they wish to.

Participants in this group performs exercise 3 times a week (150 minutes total) according to the recommended exercise guidelines and will sit in the exercise laboratory for 15 minutes whilst the experimental group uses the sauna.

Participants in this group performs exercise 3 times a week (150 minutes total) according to the recommended exercise guidelines and incorporates sauna bathing (heat therapy) immediately after exercise.

50 minutes of exercise, consisting of 20 minutes of resistance followed by 30 minutes of aerobic, three times a week for eight weeks.

15 minutes of sauna exposure immediately after exercise intervention, three times a week for eight weeks.

Moor instrument (moorVMS) near infrared spectroscopy (NIRS) will be used with a post occlusive reactive hyperaemia (PORH) protocol to assess haemoglobin concentration. The moorVMS-NIRS uses the established spatially resolved spectroscopy technique to measure absolute concentrations of oxygenated haemoglobin in human tissue. The system measures oxygenation using a probe which is placed in contact with the skin. Each probe consists of a detector head which contains two identical photodiodes and an emitter head which contains two near infrared light emitting diodes (LED) emitting light at approximately 750nm and 850nm. Light from the emitter head enters the tissue where it is subject to scattering and absorption. A small proportion of the incident light passes through the tissue to the photodiodes. The resulting photocurrents are amplified and acquired by the instrument.

Moor instrument (moorVMS) laser doppler flowmetry (LDF) will be used with a post occlusive reactive hyperaemia (PORH) protocol to assess bloodflow (flux). The moorVMS-LDF uses the laser doppler technique where a low power laser light is transmitted via an optic fibre to the tissue. The light is scattered by tissue and moving blood cells and its frequency is Doppler broadened. Some of the scattered light is collected by one or more optic fibres and transmitted to a photo detector. The resulting photo current is electronically processed to produce the laser Doppler flux (blood flow) signal. The average Doppler frequency shift is directly proportional to the average speed of the blood cells.

Inclusion Criteria: At least one conventional cardiovascular risk factor but asymptomatic for coronary heart disease or diabetes Exclusion Criteria: Use of sauna more than once a week, Exercise more than 30 minutes a week, low blood pressure, any diagnosed and/or symptomatic cardiovascular disease, musculoskeletal injury, any other physical or mental condition that will prohibit the participation in the experiment, participation to any other study at the same time.