The Effects of Post Aerobic Exercise Hot Water Immersion on Physiological and Perceptual Responses in Physically Inactive Middle-aged Adults

Study Overview
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Brief Summary
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This study will investigate the effects of post moderate intensity aerobic exercise hot water immersion on physiological and perceptual responses in physically inactive middle-aged adults when compared to moderate intensity aerobic exercise and hot water immersion alone.

Detailed Description
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A large number of middle aged adults do not achieve the minimum recommended amount of physical activity. This consequently increases the risk of cardiovascular disease and all-cause mortality. Although below the recommended physical activity guidelines, it is important to highlight that a considerable proportion of these individuals do take part in some form of physical activity within their weekly routines. Hence, identifying complementary therapies that can enhance the health benefits from smaller amounts of exercise are of great value for many physically inactive middle-aged adults. An in increase in body temperature from a single session of passive heating has been shown to mimic many of the beneficial physiological responses of exercise, such as, an increase in heart rate, skin blood flow and an increase in circulating angiogenic factors. However, lab based studies often push participants to the limit of thermal tolerance which may reduce long term adherence in the real world. Therefore, this study will investigate whether the use of post exercise hot water immersion can prolong and / or intensify exercise mediated physiological responses that underpin health benefits, whilst also assessing the perceptual responses, in comparison to exercise and hot water immersion alone. Through the use of a repeated measures design, participants will randomly take part in three conditions; 1) post exercise hot water immersion (30 minutes of moderate intensity cycling followed by 10 minutes of supine rest and 30 minutes of whole body hot water immersion at 40°C); 2) aerobic exercise (30 minutes of moderate intensity cycling followed by 10 minutes of supine rest and 30 minutes of seated rest at room temperature); 3) hot water immersion condition (30 minutes of whole body hot water immersion at 40°C followed by 10 minutes of supine rest and 30 minutes of whole body hot water immersion at 40°C). Each condition will be separated by a minimum of 1-week. Outcome measures will either be assessed at regular intervals or at 0, 30, 70 and 100 minute time points for each condition.

Official Title
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The Effects of Post Aerobic Exercise Hot Water Immersion on Physiological and Perceptual Responses in Physically Inactive Middle-aged Adults

Conditions
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Healthy Aging

Intervention / Treatment
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* Device: Post exercise hot water immersion
* Device: Exercise
* Device: Hot water immersion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males and post menopausal females Aged between 40 - 60 years BMI of 18.5 - 34.9 kg/m2 Over the last 6 months has participated in less than 150 mins of moderate intensity physical activity or 75 mins of vigorous activity or a combination of both, but takes part in some form of physical activity within their weekly routine. Maximal oxygen uptake categorised as 'fair' for a given age group. Exclusion Criteria: Previous myocardial infarction or cerebrovascular event Any signs or symptoms of cardiovascular issues High blood pressure: SBP >180 mmHg and / or DBP >100 mmHg Orthostatic hypotension: Drop of SBP > 20mmHg and / or DBP >10 mmHg upon standing. Changed blood pressure medication in the 6-month period prior to the study Plan to change any form of relevant medication during study period Suffers from diabetes Suffers from severe asthma Currently have any infections or symptoms of an infection (e.g. COVID-19 etc) Suffers from a neurodegenerative disease Cannot understand and/or fully cooperate with the study protocol Exercise-limiting comorbidity (e.g. angina, chronic lung disease, arthritis etc) Severe peripheral neuropathy (cannot sense temperature) Current smoker or have stopped in the last 3 months Any skin conditions including ulcerations Exposed to high temperatures in the last 4-weeks (e.g. holiday, spa, sun beds etc) Use of antioxidant supplements in the last 6-weeks

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Post exercise hot water immersion<br>Moderate intensity cycling for 30 minutes, followed by a 10-minute transfer period and then 30 minutes of whole-body hot water immersion. | Device: Post exercise hot water immersion<br>* Participants will complete 30 minutes of cycling on a lode bicycle ergometer (50% of VO2max), followed by a 10-minute transfer period and then 30 minutes of whole-body hot water immersion in a hot tub (water temperature 40°C).<br>|
| Active Comparator: Exercise<br>Moderate intensity cycling for 30 minutes. | Device: Exercise<br>* Participants will complete 30 minutes of cycling on a lode bicycle ergometer (50% of VO2max).<br>|
| Active Comparator: Hot water immersion<br>Whole-body hot water immersion for 30 minutes, followed by a 10-minute transfer period and then an additional 30 minutes of whole-body hot water immersion. | Device: Hot water immersion<br>* Participants will complete 30 minutes of whole-body hot water immersion in a hot tub (water temperature 40°C), followed by a 10-minute transfer period and then an additional 30 minutes of whole-body hot water immersion in a hot tub (water temperature 40°C).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in circulating plasma nitrite (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery total shear rate (S-1) | Terason ultrasound recording of the brachial and superficial femoral artery | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery antegrade shear rate (S-1) | Terason ultrasound recording of the brachial and superficial femoral artery. | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery retrograde shear rate (S-1) | Terason ultrasound recording of the brachial and superficial femoral artery | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery diameter (mm) | Terason ultrasound recording of the brachial and superficial femoral artery | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery blood flow (ml/min) | Terason ultrasound recording of the brachial and superficial femoral artery. | Measured at 0, 30, 70 and 100 minutes | 
| Change in brachial artery compliance (μm/mmHg) | Terason ultrasound recording of the brachial artery. Brachial artery compliance will be calculated by using the change in blood volume and blood pressure | Measured at 0, 30, 70 and 100 minutes | 
| Change in systolic blood pressure (mmHg) | Measured using an automated blood pressure cuff | Measurements taken at 10 minute intervals up to 100 minutes | 
| Change in diastolic blood pressure (mmHg) | Measured using an automated blood pressure cuff | Measurements taken at 10 minute intervals up to 100 minutes | 
| Change in mean arterial pressure (mmHg) | Measured using an automated blood pressure cuff. Mean arterial pressure will be calculated by using systolic and diastolic blood pressure | Measurements taken at 10 minute intervals up to 100 minutes | 
| Change in pulse pressure (mmHg) | Measured using an automated blood pressure cuff. Pulse pressure will be calculated using systolic and diastolic blood pressure | Measurements taken at 10 minute intervals up to 100 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in circulating serum Interleukin-6 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Interleukin-10 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Interleukin-8 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Interleukin-1Ra (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Vascular endothelial growth factor (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Endothelin-1 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Circulating serum Monocyte chemoattractant protein-1 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Matrix metallopeptidase-2 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Change in circulating serum Matrix metallopeptidase-9 (pg/ml) | Venous blood sample | Measured at 0, 30, 70 and 100 minutes | 
| Energy expenditure (kcal/h-1) | Measured initially by breath by breath analysis through the use of a Ultima and calculated via indirect calorimetry | Gas measurements taken continually up to 70 minutes. Energy expenditure calculated from the 30 minutes of exercise, hot water immersion and/or rest periods. | 
| Change in thermal comfort | Thermal comfort Likert scale from a positive score of +5 very comfortable (maximum) to a negative score of -5 very uncomfortable (minimum) | Measured at 10 minute intervals up to 100 minutes | 
| Change in thermal sensation | Thermal sensation Likert scale from +5 (maximum) hot to -5 cold (minimum) | Measured at 10 minute intervals up to 100 minutes | 
| Change in basic affect | Basic affect Likert scale from a positive score of +5 very good (maximum) to a negative score of -5 very bad (minimum) | Measured at 10 minute intervals up to 100 minutes | 
| Change in physical activity enjoyment scale | Feelings about exercise and / or passive heating on a Likert scale from a positive score of 1 (maximum) to a negative score of 7 (minimum) | Measured  12 minutes post intervention |