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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
TRIPLE
Enrollment
18
Flavonoid-rich cocoa powder, containing 100mg total flavanols per 316mg.
Microcrystalline filler, containing 0mg total flavanols.
Research Institute for Sport & Exercise Sciences
Liverpool, United Kingdom
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.
Time frame: 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.
Time frame: Over 3 week period (After 7 days of each intervention).
Heart rate
Heart rate will be measured during moderate and severe-intensity exercise bouts, by short-range telemetry.
Time frame: 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
Time frame: 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
Time frame: 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.
Time frame: 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.
Time frame: Over 3 week period (After 7 days of each intervention). Measured immediately before and after exercise
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