Acute effects of MitoQ on vascular endothelial function are influenced by cardiorespiratory fitness and baseline FMD in middle-aged and older adults.

A key mechanism promoting vascular endothelial dysfunction is mitochondrial-derived reactive oxygen species (mtROS). Aerobic exercise preserves endothelial function in preclinical models by lowering mtROS. However, the effects of mtROS on endothelial function in exercising and non-exercising adults is limited. In a double-blind, randomized, placebo-controlled crossover study design 23 (10 M/13 F, age 62.1 ± 11.5 years) middle-aged and older (MA/O, ≥45 years) adults were divided into two groups: exercisers (EX, n = 11) and non-exercisers (NEX, n = 12). All participants had endothelial function (brachial artery flow-mediated dilatation, FMDBA) measured before and ∼1 h after mitoquinone mesylate (MitoQ) (single dose, 80 mg) and placebo supplementation. A two-way repeated measures ANOVA was used to determine the effects of MitoQ and placebo on FMDBA. Pearson correlations assessed the association between the change in FMDBA with MitoQ and baseline FMDBA and cardiorespiratory fitness (CRF). Compared with placebo, MitoQ increased FMDBA in NEX by + 2.1% (MitoQ pre: 4.9 ± 0.4 vs. post: 7.0 ± 0.4 %, P = 0.004, interaction) but not in EX (P = 0.695, interaction). MitoQ also increased endothelial function in adults with a FMDBA <6% (P < 0.0001, interaction) but not >6% (P = 0.855, interaction). Baseline FMDBA and CRF were correlated (r = 0.44, P = 0.037), whereas the change in FMDBA with MitoQ was inversely correlated with CRF (r = -0.66, P < 0.001) and baseline FMDBA (r = -0.73, P < 0.0001). The relationship between the change in FMDBA and baseline FMDBA remained correlated after adjusting for CRF (r = -0.55, P = 0.007). These data demonstrate that MitoQ acutely improves FMDBA in NEX and EX adults who have a baseline FMDBA <6%. KEY POINTS: A key age-related change contributing to increased cardiovascular disease (CVD) risk is vascular endothelial dysfunction due to increased mitochondrial-derived reactive oxygen species (mtROS). Aerobic exercise preserves endothelial function via suppression of mtROS in preclinical models but the evidence in humans is limited. In the present study, a single dose of the mitochondria-targeted antioxidant, mitoquinone mesylate (MitoQ), increases endothelial function in non-exercisers with lower cardiorespiratory fitness (CRF) but not in exercisers with higher CRF. The acute effects of MitoQ on endothelial function in middle-aged and older adults (MA/O) are influenced by baseline endothelial function independent of CRF. These data provide initial evidence that the acute MitoQ-enhancing effects on endothelial function in MA/O adults are influenced, in part, via CRF and baseline endothelial function.

Cardiorespiratory fitness is associated with estimates of myocardial perfusion: influence of age and sex.

Cardiorespiratory fitness (CRF) and the subendocardial viability ratio (SEVR) decline with age and predict future cardiovascular disease (CVD) events in a sex-dependent manner. However, the relation between CRF and SEVR in apparently healthy males and females across the age span is largely unknown. We hypothesized higher CRF is associated with greater SEVR in older females but not in males. Two-hundred sixty-two (126 M/136 F, age range 20-84 yr) participants underwent measures of CRF (maximal O2 consumption, V̇o2max) and SEVR (pulse wave analysis, PWA). A two-way analysis of variance (ANOVA) was used to examine differences in baseline characteristics between younger (<45 yr) and middle-aged and older (MA/O, ≥45 yr) males and females. Bivariate correlations assessed the relation between CRF, SEVR, and age in males and females. Partial correlations adjusted for CVD risk factors and medications. MA/O females had the lowest CRF and SEVR compared with all other groups (P < 0.05, both). SEVR was negatively correlated with age (r = -0.29) and positively correlated with CRF (r = 0.53) in females (P < 0.05, both) that persisted after controlling for CVD risk factors and medications (P < 0.05, all). SEVR was correlated with CRF in males only after adjusting for CVD risk factors and medications (r = 0.26, P < 0.05). These findings collectively demonstrate higher CRF is associated with greater SEVR in males and females after adjusting for CVD risk factors and medications, therefore highlighting subtle sex-specific nuances that warrant further investigation.NEW & NOTEWORTHY Cardiorespiratory fitness (CRF) and the subendocardial viability ratio (SEVR) are independent predictors of mortality and decline with age. However, the sex-specific relationship between CRF and SEVR with aging in adult males and females is unknown. Our findings demonstrate higher CRF is associated with greater age-related SEVR in males and females, after adjusting for traditional cardiovascular disease (CVD) risk factors and medications. However, subtle sex-related nuances exist in the relationship between SEVR and CRF that require further investigation.

Perivascular adipose tissue-mediated arterial stiffening in aging and disease: An emerging translational therapeutic target?

Cardiovascular diseases (CVD) are the leading cause of mortality in modernized societies. Arterial stiffening with aging and disease is a key pathological event leading to increased CVD morbidity and mortality. Perivascular adipose tissue (PVAT) is a fat depot not widely studied yet has direct and profound effects on arterial stiffening. Identifying PVAT as a novel therapeutic target to lower arterial stiffness and thereby CVD risk has potentially important clinical ramifications. Thus, herein, we will overview the current preclinical evidence and the associated mechanisms for PVAT to promote arterial stiffness with aging and other disease conditions. We will also discuss viable translational lifestyle and pharmacological interventions for altering PVAT function that may de-stiffen arteries. Last, the translational potential for PVAT as a therapeutic target to lower arterial stiffness and CVD risk for clinical populations will be discussed.

Influence of curcumin on performance and post-exercise recovery.

Intense exercise, especially involving eccentric contractions, causes muscle damage concomitant with increased reactive oxygen species (ROS), which can lead to increased fatigue and decrements in physical performance. Additionally, inflammatory cytokines and advanced glycation end-products (AGEs) are produced as a result of eccentric exercise and may further lead to decreased exercise performance. Nutritional interventions may provide an avenue to respond to and reduce the symptoms associated with muscle damage. Of recent interest, curcumin, the main constituent in the spice turmeric, has been the focus of various studies considering post-exercise recovery. Curcumin has potent anti-oxidant and anti-inflammatory properties and can reduce the accumulation of AGEs. This review considers the current evidence for curcumin to impact muscle recovery following exercise to improve performance and the potential mechanisms of action. To date, clinical studies have considered the potential role of curcumin to reduce muscular damage following treadmill running (downhill and flat), conventional walking/running, cycling (acute and chronic), single-leg jumping (downhill), and eccentric muscular fitness exercises of the upper and lower body (single- and double-leg). Studies have been conducted in sedentary to highly active men and women, both young and old, with supplementation duration lasting from a single, acute dose to daily dosages for three months. Various curcumin-based interventions have improved self-perceived measures of pain and tenderness, reduced evidence of muscle damage, ameliorated inflammatory markers, increased markers of antioxidant capacity, diminished markers of oxidative stress, reduced markers of AGEs, and attenuated loss in mean power of single-leg sprints. However, these findings have not been consistently reported.

Curcumin and arterial function in health and disease: impact on oxidative stress and inflammation.

PURPOSE OF REVIEW: The purpose of this review is to provide a concise overview of the polyphenol curcumin for improving arterial health, specifically endothelial function and arterial stiffness, to reduce cardiovascular disease (CVD) risk and to highlight potential mechanisms of action by which curcumin may improve artery function. RECENT FINDINGS: The primary findings of this review support the notion for curcumin to improve arterial health both with aging and obesity. There are few clinical trials on curcumin, and those that currently exist are small in scale but provide evidence for curcumin to improve endothelial function in older adults and reduce arterial stiffness in young, obese men. The antioxidant and anti-inflammatory properties of curcumin appear to be important targets of curcumin that are related to improved arterial health. Mechanistic studies have revealed superoxide dismutase, heme oxygenase-1 and nuclear factor erythroid 2-related factor 2 as emerging targets for the beneficial effects of curcumin on the vasculature. SUMMARY: In summary, the efficacy of curcumin for improving arterial function is promising in the limited number of clinical studies performed to date. Still, much investigation is needed to elucidate the effectiveness of curcumin for improving arterial health to lower CVD risk.

Aortic Stiffness Is Associated With Higher Nighttime Ambulatory Blood Pressure in Middle-Aged and Older Adults.

PURPOSE: The objective of this study was to determine the relationship between aortic stiffening and brachial and central ambulatory blood pressure (AMBP) in a nonclinical sample of middle-aged and older adults (MA/O). We hypothesized aortic stiffness would be positively associated with 24-hr, daytime, and nighttime brachial and central AMBP. METHODS: Fifty-one participants aged ≥50 yr (21 males and 30 females, mean age 63.4 ± 9.0 yr) with a body mass index <35 kg/m 2 who also had a resting brachial blood pressure (BP) <160/100 mmHg with or without BP medications were recruited for this cross-sectional analysis. All participants underwent measures of aortic stiffness (carotid-femoral pulse wave velocity [cfPWV]) and 24-hr AMBP monitoring. Bivariate correlations assessed the relationship between cfPWV, brachial, and central AMBP. Partial correlations were used to independently adjust for traditional cardiovascular disease (CVD) risk factors including age, sex, waist circumference, glucose, and augmentation index normalized to heart rate 75 bpm, a surrogate measure of arterial stiffness, and in a multivariable combined model. RESULTS: Nighttime brachial systolic BP ( r = 0.31) and central systolic BP ( r = 0.30) were correlated with cfPWV in the multivariable combined model ( P ≤ .05). Nighttime brachial pulse pressure and central pulse pressure were correlated with cfPWV after independently adjusting for all CVD risk factors ( P ≤ .05, all) but not when combined in the multivariable model ( P > .05). CONCLUSIONS: Higher nighttime brachial and central AMBP with older age are related, in part, to greater aortic stiffening. Therefore, interventions to lower or prevent aortic stiffening may also lower nighttime BP in MA/O adults to lower CVD risk.

Nutraceuticals in the Prevention and Therapeutic Treatment of Cardiovascular and Cerebrovascular Disease.

PURPOSE: This review overviews and highlights arterial stiffening as a key physiological process and target for the prevention and/or lowering of cardio- and cerebrovascular disease (collectively CVD) risk. METHODS: We identified nutraceutical approaches from randomized controlled trials and discussed the associated mechanisms by which these compounds lower age-related arterial stiffness. Age-related CVD are the leading cause of mortality in modernized societies. Arterial dysfunction, specifically stiffening of the large elastic arteries during midlife, is a key physiological process resulting in increased CVD risk. Current pharmaceutical approaches for lowering age-related arterial stiffness have limited efficacy, thus highlighting the need to identify novel approaches for lowering arterial stiffness and thereby CVD risk. Lifestyle interventions are a historical first-line approach to prevent and/or lower the adverse arterial stiffening effects observed with aging. Nutraceutical interventions, defined as a food or part of a food providing health benefits, are a nonpharmacological, novel lifestyle approach to lower age-associated arterial stiffness. Therefore, identifying nutraceutical approaches to lower CVD risk is clinically significant. SUMMARY: This review provides a basic, yet essential, understanding for emerging nutraceutical strategies for the prevention and therapeutic treatment of CVD.

Mitochondrial-targeted antioxidant ingestion acutely blunts VO2max in physically inactive females.

PURPOSE: To determine the acute effects of a mitochondrial targeting antioxidant (MitoQ) on the metabolic response during exercise. METHODS: Nine (n = 9) physically inactive females (age 47 ± 22 years) performed two trials (Placebo and MitoQ) in a double-blind randomized cross-over design. In both trials, participants performed an exercise protocol consisting of 3-min stages at submaximal workloads followed by a ramp protocol to volitional exhaustion. Participants received either Placebo or MitoQ (80 mg) 1 h prior to exercise. Indirect calorimetry and cardiovascular measurements were collected throughout the duration of the exercise bout. RESULTS: Submaximal metabolic and cardiovascular variables were not different between trials (p > 0.05). VO2max was higher (p = 0.03) during Placebo (23.5 ± 5.7 mL kg min-1 ) compared to MitoQ (21.0 ± 6.6 mL kg min-1 ). Maximal ventilation was also higher (p = 0.02) in Placebo (82.4 ± 17.7 L/min) compared to MitoQ (75.0 ± 16.8 L/min). Maximal cardiovascular variables and blood lactate were not different between trials (p > 0.05). CONCLUSION: An acute dose of MitoQ blunted VO2max , which was primarily mediated by impairment of ventilatory function. These data suggest that the acute accumulation of exercise-induced mitochondrial reactive oxygen species (mtROS) are necessary for maximal aerobic capacity. Further research is warranted on mtROS-antioxidant cell signaling cascades, and how they relate to mitochondrial function during exercise.

Greater aortic perivascular adipose tissue density is associated with aging, aortic stiffness, and central blood pressure in humans.

Aging results in aortic perivascular adipose tissue (aPVAT)-mediated aortic stiffening in preclinical animal models to promote cardiovascular dysfunction. We hypothesized that greater human aPVAT density will be associated with aging, higher aortic stiffness, and blood pressure (BP). Fourteen apparently healthy adults (6 M/8 F, age range 20-79 yr) were recruited for this study. Aortic stiffness, assessed by carotid-femoral pulse wave velocity (cfPWV), resting aortic BP via pulse wave analysis, and aPVAT and abdominal visceral adipose tissue (VAT) density by computed tomography attenuation were acquired. aPVAT and epididymal (visceral) fat from young (4-6 mo) and old (27-29 mo) mice were used for ex vivo-conditioned media intrinsic mechanical stiffness experiments. Compared with younger adults, older adults had higher cfPWV (8.6 ± 0.4 vs. 6.2 ± 0.6 m/s, P < 0.05) and greater aPVAT attenuation (-80.2 ± 2.0 vs. -95.9 ± 1.5 HU, P < 0.05), but not VAT attenuation (P > 0.05). aPVAT-conditioned media from old mice compared with young mice increased intrinsic mechanical stiffness of the aorta (4,519 ± 510 vs. 2,325 ± 563 kPa, P < 0.05), which was not observed with epididymal fat-conditioned media from old mice (P > 0.05). aPVAT, but not VAT density, was positively associated with age (r = 0.89), cfPWV (r = 0.56), resting augmentation index normalized to heart rate 75 (AIxHR75; r = 0.67), aortic systolic BP (r = 0.58), and aortic pulse pressure (PP; r = 0.59; P < 0.05, all) and were independent of VAT density (P < 0.05, all). These data herein provide evidence for aPVAT as a novel fat depot and therapeutic target to lower aortic stiffness and future cardiovascular disease risk with aging in humans.NEW & NOTEWORTHY Aortic perivascular adipose tissue (aPVAT) promotes age-related aortic stiffening in preclinical animal models, but the relation between aPVAT density and cardiovascular function in adults is unknown. We demonstrate that aPVAT, but not abdominal visceral adipose tissue density, is positively associated with aging, aortic stiffness, and higher resting aortic blood pressure in apparently healthy adults. These findings provide novel evidence for aPVAT as a viable therapeutic target for improving cardiovascular function in humans.

Coconut sugar derived from coconut inflorescence sap lowers systolic blood pressure and arterial stiffness in middle-aged and older adults: a pilot study.

Nutraceutical-based interventions hold promise to reduce blood pressure (BP) and arterial stiffness, which are two cardiovascular disease (CVD) risk factors. However, the effects of coconut sap powder (CSP), an Asian sweetener and novel nutraceutical, on BP and arterial stiffness in middle-aged and older adults (MA/O, ≥45 yr) has yet to be established. We hypothesized CSP will decrease BP and arterial stiffness in MA/O adults. In a double-blind, randomized, placebo-controlled study design, 19 (age 55.3 ± 2.1 yr) MA/O adults completed measures of brachial and carotid BP, and arterial stiffness [carotid-femoral pulse wave velocity (cfPWV), common carotid artery (CCA) ß-stiffness, compliance, distensibility, and Young's and Peterson's Elastic moduli] before and after 8 wk of CSP (1.5 g/day) or placebo (1.5 g/day). A two-way repeated-measures analysis of variance was used to compare group mean differences. Compared with placebo, CSP lowered brachial systolic BP (SBP) (CSP pre: 117.4 ± 2.9 vs. post: 109.0 ± 2.4 mmHg, P < 0.05), but not carotid SBP (P = 0.12). CSP also lowered Young's (CSP pre: 5,514.4 ± 1,115.4 vs. post: 3,690.6 ± 430.9 kPa) and Peterson's elastic moduli (CSP pre: 22.2 ± 4.4 vs. post: 19.2 ± 4.5 kPa) (P < 0.05, both). A trend for CSP to lower CCA ß-stiffness (P = 0.06) and increase CCA compliance (P = 0.07) was also observed. Arterial stiffness assessed by cfPWV did not change (P > 0.05). No inflammatory or antioxidant biomarkers were affected by CSP. In summary, 8 wk of CSP lowers brachial SBP and CCA mechanical stiffness indicating a potential cardioprotective effect in MA/O adults.NEW & NOTEWORTHY Blood pressure (BP) and arterial stiffness are important predictors of cardiovascular health with aging. Nutraceuticals are an easy-to-implement lifestyle strategy demonstrating promise to effectively lower BP and arterial stiffness with aging and ultimately cardiovascular disease risk. We demonstrate that coconut sap powder (CSP), a traditional Asian sweetener, lowers brachial systolic BP and carotid artery mechanical stiffness in middle-aged and older (MA/O) adults. These findings provide initial evidence for the CSP-related cardioprotective effects in MA/O adults.

Age-related carotid extra-media thickening is associated with increased blood pressure and arterial stiffness.

Ageing results in higher blood pressure and arterial stiffening leading to increased cardiovascular disease (CVD) risk. The extra-media thickness (EMT) is a composite measure of the arterial adventitia, perivascular adipose tissue (PVAT) and the jugular vein, but the association among EMT and ageing, blood pressure and arterial stiffness is largely unknown. We hypothesized that EMT is associated with ageing, blood pressure and arterial stiffness. Fifty (18M/32F, age range 20-79 years.) individuals underwent measures of EMT (media-adventitia border to jugular lumen interface) via ultrasonography, blood pressure (brachial; carotid), arterial stiffness (carotid beta-stiffness, distensibility and Young's modulus) and body composition (dual X-ray absorptiometry). Independent two-tailed t-tests compared characteristics between young and middle-aged/older adults (MA/O). Bivariate correlations assessed the relation between EMT, ageing, blood pressure and arterial stiffness endpoints. Partial correlations were used to adjust for age, sex, body mass index (BMI) and body fat percentage. Compared to young, MA/O adults had higher EMT, blood pressure, arterial stiffness, BMI and BF% (all, p ≤ 0.05). Carotid EMT was positively correlated with age (r = 0.46), brachial SBP (r = 0.32), carotid SBP (r = 0.42), PP (r = 0.42), beta-stiffness (r = 0.37) and Young's elastic modulus (r = 0.43) (all, p ≤ 0.05), and negatively correlated with carotid distensibility (r = -0.34, p ≤ 0.05). All endpoints correlated with EMT remained after adjusting for BMI, BF% and sex (p ≤ 0.05). These data suggest EMT is a clinically relevant target that may be associated with age-related CVD risk in humans, yet further investigation is required to elucidate the role of EMT in age-related increases in blood pressure and arterial stiffness.

Dietary fat and alcohol in the prediction of indices of vascular health among young adults.

OBJECTIVES: Arterial stiffness, particularly of the aorta, is an independent predictor of future cardiovascular disease, all-cause mortality, and hypertension. Arterial stiffening may be caused or exacerbated by the composition of the diet. Current research has indicated that habitual dietary patterns may influence arteriosclerosis, or the thickening and hardening of the artery walls, but has yet to identify a specific food group as the culprit. In young, college-aged adults, dietary fat intake and alcohol consumption tend to be higher compared to other periods throughout the life cycle. Therefore, the purpose of this study was to determine the influence of dietary fat and alcohol consumption on the vascular health of apparently healthy young adults. METHODS: The data collected were assessed to determine if dietary fat and alcohol in young (18-30 y), college-aged adults (n = 50) were independent predictors of an increase in arterial stiffening. Vascular health was determined by the carotid-femoral pulse-wave velocity and the augmentation index corrected for a heart rate of 75 beats/min; dietary patterns were assessed using the Dietary Health Questionnaire II. RESULTS: The gold standard marker of aortic stiffness, carotid femoral pulse-wave velocity, was positively correlated with cheese consumption (R2 = 0.092, P = 0.033), alcohol consumption (R2 = 0.102, P = 0.024), and total energy/calories (%) from alcohol (R2 = 0.118, P = 0.015) in univariate analysis. In forward-selection multiple regression analysis, energy from alcohol and cheese consumption accounted for 23.7% of the variance in carotid-femoral pulse-wave velocity (P = 0.009). The augmentation index wave reflection marker was positively correlated with total dietary fat (R2 = 0.110, P = 0.019), trans fatty acids (R2 = 0.092, P = 0.032), saturated fatty acids (R2 = 0.124, P = 0.012), monounsaturated fatty acids (R2 = 0.012, P = 0.015), red-meat consumption (R2 = 0.094, P = 0.030), and discretionary fat from solids in univariate analysis (R2 = 0.137, P = 0.008). Discretionary fat from solids accounted for 13.7% of the variation in augmentation index in forward-selection multiple regression analysis (P = 0.008). CONCLUSIONS: These results indicate the potential roles of dietary fat and alcohol consumption in early vascular aging by stiffening the arteries of young, college-aged adults, which may in turn contribute to future adverse cardiovascular disease outcomes.

Healthy Vascular Aging Is Associated With Higher Cardiorespiratory Fitness.

BACKGROUND: Healthy vascular aging (HVA) and cardiorespiratory fitness (CRF) are each independently associated with lower cardiovascular disease-related mortality. It is unknown, however, whether the CRF-related reductions in cardiovascular disease risk are related to HVA. We hypothesized that HVA would be associated with higher CRF in men and women from the Ball State Adult Fitness Longitudinal Lifestyle STudy (BALL ST). METHODS: Apparently healthy men and women ≥50 yr of age from the BALL ST cohort (n = 101) who underwent a maximal cardiopulmonary exercise test to assess CRF (V˙O2peak) were included in the study. Participants were divided into either HVA, defined as brachial systolic blood pressure <140/90 mm Hg without taking medications and carotid-femoral pulse wave velocity <7.6 m/sec, or no HVA for subjects with SBP >140/90 mm Hg and/or PWV >7.6 m/sec. RESULTS: Participants with HVA had a higher age- and sex-adjusted CRF percentile (62 ± 5 vs 47 ± 3, P < .05), with women having a greater prevalence of HVA than men (36% vs 15%, P < .05). Both carotid-femoral pulse wave velocity (r =-0.27, P < .05) and brachial systolic blood pressure (r =-0.23, P < .05) were independently and inversely associated with CRF for the entire cohort. Men and women with HVA were younger having a lower body fat percentage and higher low-density lipoprotein cholesterol (P < .05, all). CONCLUSIONS: These data demonstrate that HVA is associated with higher CRF, which may partially explain the preventative cardioprotective effects of CRF.

Order of concentric and eccentric muscle actions affects metabolic responses.

BACKGROUND: Resistance exercise provides an effective stimulus for improving the metabolic plasticity of skeletal muscle, and the type of acute muscle contraction plays an important role in determining specific responses and adaptations. The purpose of the current investigation was to examine the effect of contraction order on metabolic responses by comparing monophasic concentric and eccentric squats versus a protocol incorporating alternated concentric and eccentric repetitions. METHODS: Twelve recreationally active men (21.1±1.1yr) performed three nearly identical squat protocols on separate days. Protocols varied only with contraction-type, including 4 sets × 10 reps concentric-only (CON), eccentric-only (ECC), and BOTH which alternated 5 concentric followed by 5 eccentric reps (CON-ECC; sets 1 and 3) and vice versa (ECC-CON; sets 2 and 4). The experimental trials were performed once weekly in a randomized, counter-balanced order, and expired gases were collected using a two-way non-rebreathing mask and oxygen consumption quantified with indirect calorimetry. Subjects raised (CON) and lowered (ECC) the load in 2s, and all sets (2 min) and repetitions (8 s) were separated by standardized rest intervals. RESULTS: From the BOTH protocol, the increase in metabolic rate was significantly greater (P≤0.05) during squats performed with CON-ECC order (0.60±0.11 L·min-1) compared to ECC-CON (0.44±0.07 L·min-1), but excess postexercise oxygen consumption (EPOC) was opposite, with significantly greater metabolic rate during the 2-minute rest intervals after ECC-CON squats (0.46±0.09 L·min-1) compared to CON-ECC (0.25±0.05 L·min-1). Metabolic rates during and after squats were significantly greater (P≤0.05) with CON (0.63±0.09; 0.49±0.10 L·min-1) compared to ECC (0.34±0.04; 0.20±0.04 L·min-1), respectively. CONCLUSIONS: These data present an interesting paradigm regarding the contraction-dependent metabolic responses to monophasic resistance exercise and suggest a greater EPOC following concentric versus eccentric muscle actions.