Dietary Nitrate Supplementation and Exercise Performance: Implications for Taekwondo Athletes

( Charles L. Stebbins ) 국제태권도학회 2016 Journal of the International Association for Taekw Vol.3 No.1

Presently, very little is known about the potential beneficial effects of dietary supplements on Taekwondo performance. Research into this area should focus on supplements that can potentiate the function of those physiological systems that optimize peak performance during Taekwondo competition (e.g., anaerobic and aerobic metabolism, power production, and O₂ delivery). One candidate that may meet these criteria is dietary nitrate (NO₃-). In general, NO₃- supplements (consumed acutely or chronically) have been shown to decrease the O₂ cost of exercise, prolong the onset of fatigue, increase O₂ delivery, reduce the work of the heart, enhance blood flow to contracting muscle, improve neuromuscular efficiency, and improve peak force production in healthy humans. However, the effects of NO₃- on performance in elite athletes have been less obvious. Reasons for these differential responses are unclear, but factors such as dose, duration of supplementation, intensity and duration of training, and exercise mode may be intervening factors.

Cardiovascular effects of resveratrol supplementation atrest and during exercise in humans

( Heather L Clifton ),( Hyun Bae Kim ),( Jong Kyung Kim ),( Charles L Stebbins ) 한국운동영양학회 2012 Physical Activity and Nutrition (Phys Act Nutr) Vol.16 No.4

Resveratrol is a polyphenol found in food sources such as peanuts, berries, grapes and red wine. It has been touted for, among other actions, beneficial effects on the cardiovascular system. Consequently, it has been marketed as a nutritional supplement for healthy individuals. Using a double-blind, crossover design, we tested the hypothesis that chronic supplementation with resveratrol attenuates blood pressure at rest and during skeletal muscle contraction and augments endothelial function and exercise-induced increases in skeletal muscle blood flow in this group.Mean arterial blood pressure (MAP), heart rate (HR), endothelial function (evaluated via flow mediated dilation) brachial artery diameter (ultrasound) and rhythmic forearm contraction-induced increases in skeletal muscle blood flow (Doppler/ultrasound) were assessed before and after chronic (500 mg/day for 28-32 days, n = 14) supplementation with resveratrol. Compared to placebo, resveratrol supplementation had modest effects on resting MAP(82 ± 2 vs. 80 ± 2 mmHg) (P < 0.05). However, no effects of this polyphenol were seen on HR, flow mediated dilation or exercise-induced increases in MAP, brachial artery diameter or blood flow. We concluded that 30 days of supplementation with a commercially available dose of resveratrol (500 mg/day) have minimal, if any, beneficial cardiovascular effects in healthy individuals and do not improve endothelial or cardiovascular function during exercise.

Effects of Ovarian Cycle on Hemodynamic Responses during Dynamic Exercise in Sedentary Women

최현민,Charles L Stebbins,노호성,김미송,장명재,김종경 대한약리학회 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.6

This study tested the hypothesis that effects of the menstrual cycle on resting blood pressure carry over to dynamic exercise. Eleven healthy females were studied during the early (EP; low estrogen,low progesterone) and late follicular (LP; high estrogen, low progesterone) menstrual phases. Stroke volume (SV), heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), and total vascular conductance (TVC) were assessed at rest and in response to mild and moderate cycling exercise during EP and LP. During EP, compared to LP, baseline SBP (111±1vs. 103±2 mmHg), DBP (71±2 vs. 65±2 mmHg) and mean arterial pressure (MAP) (84±2 vs. 78±1mmHg) were higher and TVC (47.0±1.5 vs. 54.9±4.2 ml/min/mmHg) was lower (p< 0.05). During exercise, absolute values of SBP (Mild: 142±4 vs. 127±5 mmHg; Moderate: 157±4 vs. 144±5 mmHg)and MAP (Mild: 100±3 vs. 91±3 mmHg; Moderate: 110±3 vs. 101±3 mmHg) were also higher, while TVC was lower (Mild: 90.9±5.1 vs. 105.4±5.2 ml/min/mmHg; Moderate: 105.4±5.3 vs. 123.9±8.1 ml/min/mmHg) during EP (p<0.05). However, exercise-induced increases in SBP, MAP and TVC at both work intensities were similar between the two menstrual phases, even though norepinephrine concentrations were higher during LP. Results indicate that blood pressure during dynamic exercise fluctuates during the menstrual cycle. It is higher during EP than LP and appears to be due to additive effects of simultaneous increases in baseline blood pressure and reductions in baseline TVC.

Effects of Ovarian Cycle on Hemodynamic Responses during Dynamic Exercise in Sedentary Women

Choi, Hyun-Min,Stebbins, Charles L.,Nho, Hosung,Kim, Mi-Song,Chang, Myoung-Jei,Kim, Jong-Kyung The Korean Society of Pharmacology 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.6

This study tested the hypothesis that effects of the menstrual cycle on resting blood pressure carry over to dynamic exercise. Eleven healthy females were studied during the early (EP; low estrogen, low progesterone) and late follicular (LP; high estrogen, low progesterone) menstrual phases. Stroke volume (SV), heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), and total vascular conductance (TVC) were assessed at rest and in response to mild and moderate cycling exercise during EP and LP. During EP, compared to LP, baseline SBP ($111{\pm}1$ vs. $103{\pm}2$ mmHg), DBP ($71{\pm}2$ vs. $65{\pm}2$ mmHg) and mean arterial pressure (MAP) ($84{\pm}2$ vs. $78{\pm}1$ mmHg) were higher and TVC ($47.0{\pm}1.5$ vs. $54.9{\pm}4.2$ ml/min/mmHg) was lower (p<0.05). During exercise, absolute values of SBP (Mild: $142{\pm}4$ vs. $127{\pm}5$ mmHg; Moderate: $157{\pm}4$ vs. $144{\pm}5$ mmHg) and MAP (Mild: $100{\pm}3$ vs. $91{\pm}3$ mmHg; Moderate: $110{\pm}3$ vs. $101{\pm}3$ mmHg) were also higher, while TVC was lower (Mild: $90.9{\pm}5.1$ vs. $105.4{\pm}5.2$ ml/min/mmHg; Moderate: $105.4{\pm}5.3$ vs. $123.9{\pm}8.1$ ml/min/mmHg) during EP (p<0.05). However, exercise-induced increases in SBP, MAP and TVC at both work intensities were similar between the two menstrual phases, even though norepinephrine concentrations were higher during LP. Results indicate that blood pressure during dynamic exercise fluctuates during the menstrual cycle. It is higher during EP than LP and appears to be due to additive effects of simultaneous increases in baseline blood pressure and reductions in baseline TVC.

Effects of Ovarian Cycle on Hemodynamic Responses during Dynamic Exercise in Sedentary Women

Hyun-Min Choi,Charles L. Stebbins,Hosung Nho,Mi-Song Kim,Myoung-Jei Chang,Jong-Kyung Kim 대한생리학회-대한약리학회 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.6

This study tested the hypothesis that effects of the menstrual cycle on resting blood pressure carry over to dynamic exercise. Eleven healthy females were studied during the early (EP; low estrogen, low progesterone) and late follicular (LP; high estrogen, low progesterone) menstrual phases. Stroke volume (SV), heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), and total vascular conductance (TVC) were assessed at rest and in response to mild and moderate cycling exercise during EP and LP. During EP, compared to LP, baseline SBP (111±1 vs. 103±2 mmHg), DBP (71±2 vs. 65±2 mmHg) and mean arterial pressure (MAP) (84±2 vs. 78±1 mmHg) were higher and TVC (47.0±1.5 vs. 54.9±4.2 ml/min/mmHg) was lower (p<0.05). During exercise, absolute values of SBP (Mild: 142±4 vs. 127±5 mmHg; Moderate: 157±4 vs. 144±5 mmHg) and MAP (Mild: 100±3 vs. 91±3 mmHg; Moderate: 110±3 vs. 101±3 mmHg) were also higher, while TVC was lower (Mild: 90.9±5.1 vs. 105.4±5.2 ml/min/mmHg; Moderate: 105.4±5.3 vs. 123.9±8.1 ml/ min/mmHg) during EP (p<0.05). However, exercise-induced increases in SBP, MAP and TVC at both work intensities were similar between the two menstrual phases, even though norepinephrine concentrations were higher during LP. Results indicate that blood pressure during dynamic exercise fluctuates during the menstrual cycle. It is higher during EP than LP and appears to be due to additive effects of simultaneous increases in baseline blood pressure and reductions in baseline TVC.

Grape Seed Extract Supplementation Attenuates the Blood Pressure Response to Exercise in Prehypertensive Men

김종경,김경애,최현민,박승국,Charles L. Stebbins 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.5

We tested the hypothesis that exaggerated pressor responses observed in prehypertensive males (N = 9) during dynamic exercise are attenuated following acute dietary supplementation with grape seed extract (GSE) (i.e., a single dose). Effects of placebo and GSE (300 mg) on systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), cardiac output (CO), stroke volume (SV), total vascular conductance (TVC), and rate × pressure product (RPP) in response to two submaximal cycling workloads (40% and 60% VO2peak) were compared 2 h after ingestion of GSE or placebo on different days, 1 week apart. Endothelial function was also evaluated using flow-mediated dilation (FMD). Placebo treatment had no effect on any of the variables. GSE supplementation attenuated MAP at both workloads (40% VO2peak: 115 ± 1 vs. 112 ± 2 mmHg; 60% VO2peak: 126 ± 2 vs. 123 ± 2 mmHg) and RPP at the lower workload. Conversely, SV, CO, and TVC were augmented during both workloads. FMD was augmented by GSE (18.9 ± 2.0 vs. 12.4% ± 2.0%). These findings indicate that in exercising prehypertensive males, a single dose of GSE reduces blood pressure, peripheral vasoconstriction, and work of the heart and enhances O2 delivery; effects that may be due, in part, to endothelium-dependent vasodilation. We propose that acute GSE treatment represents an intervention that may minimize potential increases in the risk of cardiovascular events during dynamic exercise in prehypertensives.