Impact of Cocoa Flavanols on Pulmonary Oxygen Uptake Kinetics and Exercise Tolerance in Sedentary Middle-aged Adults

Study Overview
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Brief Summary
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In recent years, there has been significant interest in dietary flavonoids (biologically active plant-derived compounds) as potential therapeutics. This is due to the capacity of flavonoids to enhance processes related to energy metabolism and cardiovascular health. We are interested in implementing a short-term supplementation regime (daily cocoa-flavanoid ingestion), in order to explore the possible beneficial effects of flavonoid-based interventions on responses to exercise. Hence, the objective of our study is to examine the impact of short term cocoa-flavanoid supplementation on processes related to energy use (oxygen utilisation). Our aim is to develop a novel intervention which improves cardiovascular health and enhances exercise tolerance.

Official Title
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Investigating the Impact of Cocoa Flavanol Supplementation on Pulmonary Oxygen Uptake Kinetics and Exercise Tolerance in Sedentary Middle-aged Adults

Conditions
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Aging, Sedentary Behavior

Intervention / Treatment
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* Dietary Supplement: Cocoa flavanols
* Dietary Supplement: Placebo supplement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 35-55 years Healthy (no known cardiovascular or metabolic disorders e.g. diabetes) Do not engage in regular structured physical training (i.e. less than two sessions for 60 minutes per week, for at least 1 year Exclusion Criteria: Smokers Medical history of cardiovascular and/or metabolic disease, including diabetes and abnormal blood pressure Family history of cardiovascular disease Currently taking any medication Asthmatic Currently suffering from musculoskeletal injury Younger than 35 or older than 55 years old Known food allergies or special dietary requirements Currently taking any dietary supplements Currently engaging in >2 hours structured training per week

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 55 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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Placebo supplement, each capsule containing: 0mg total flavanols, matched for caffeine and theobromine content as experimental supplement (2.9 mg caffeine and 22.5 mg theobromine) and microcrystalline cellulose volume filler. Participants consume 4x capsules daily (2AM & 2PM after mixed meal for 7 days. | Dietary Supplement: Placebo supplement<br>* Microcrystalline filler, containing 0mg total flavanols.<br>|
| Experimental: Cocoa Flavanols<br>Experimental supplement, each capsule containing: 316 mg CocoActiv (Naturex, Netherlands: 100mg total cocoa flavanols, 2.9 mg caffeine and 22.5 mg theobromine) and microcrystalline cellulose volume filler. Participants consume 4x capsules daily (2AM & 2PM) for 7 days. | Dietary Supplement: Cocoa flavanols<br>* Flavonoid-rich cocoa powder, containing 100mg total flavanols per 316mg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygen uptake kinetics | Oxygen uptake kinetics (including time constant, time delay and amplitude of the fundamental oxygen uptake response) will be determined by modelling oxygen uptake during exercise using a mono exponential function. The oxygen uptake data is measured on a breath-by-breath basis during exercise (on a cycle ergometer) using a gas analysis system and face mask. Oxygen kinetics will be measured during three moderate-intensity step exercise tests (at 80% of the gas exchange threshold) and during one severe-intensity (60%∆) step exercise test that is completed to failure. | Over 3 week period (After 7 days of each intervention). Oxygen uptake measured for 9 minutes continuously during exercise bouts (3 min warm up period and 6 minutes of exercise transition) | 
| Exercise tolerance | Participants capacity to exercise to the limit of tolerance, measured to the nearest second. Participants are instructed to exercise at a severe-intensity exercise load (representative of 60% ∆), on a cycle ergometer until volitional exhaustion. | Over 3 week period (After 7 days of each intervention). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Heart rate will be measured during moderate and severe-intensity exercise bouts, by short-range telemetry. | Over 3 week period (After 7 days of each intervention). Measured during the length of each exercise transition (9 minutes for each moderate intensity bout). | 
| Blood pressure | Systolic and diastolic blood pressure will be assessed following 10 min of seated rest using an automated sphygmomanometer | Over 3 week period (After 7 days of each intervention). Measured over 5 minutes before any exercise testing. | 
| Blood lactate | A finger prick blood sample will be taken to measure blood lactate pre- and post-exercise of each transition using a hand-held automated blood lactate analyser | Over 3 week period (After 7 days of each intervention). Measured immediately before and after exercise | 
| Physical activity and sedentary behaviour | Physical activity levels will be assessed in the 6 days prior to visiting the laboratory by an accelerometer, worn on the hip during waking hours. | Over 3 week period (In the 6 days preceding experimental testing) | 
| Perceived workload | Perceived mental workload will be measured pre and post exercise using NASA Task Load Index and BORG rating of perceived exertion scale. | Over 3 week period (After 7 days of each intervention). Measured immediately before and after exercise |