Short term e-bicycle riding results in favorable cardiometabolic shifts in moderately active adults.

PURPOSE: Electric bikes (EB) are a form of active transportation with demonstrated health benefits. The purpose of this study was to determine the influence of riding an EB for one week on indices of cardiometabolic health in middle-aged adults. METHODS: Adults (n = 22; age = 57.1 ± 11.3 year; BMI = 27.7 ± 4.9) participated in a 2 week study. During Week 1, participants were instructed to continue regular activities. Starting Week 2 participants were provided an EB to ride at least 3 days for a minimum of 30 min·day-1. Physical activity (PA) and glucose were measured continuously. Body composition, blood lipids, glucose, insulin, hemoglobin A1c (HbA1c), plasma endothelin-1 (ET-1), and carotid-femoral pulse wave velocity (cf-PWV) were measured on days 1 and 14.Data and Statistical analyses or Statistics. Each participant served as their own control. Paired t-tests compared dependent variables between week 1 (without EB) and week 2 (with EB). RESULTS: When provided an EB for one week, moderate to vigorous PA increased by 6-9 min·day-1 (P < 0.05) and sedentary time decreased by ~ 77 min·day-1 (P < 0.05). Data from 24 h continuous glucose monitoring showed the percentage of time in healthy range (70-120 mg·dl-1 glucose) increased (P < 0.05) from week 1 to week 2. Compared to day 1, cf-PWV was lower at day 14 (P < 0.05) following one week of riding an EB. CONCLUSION: Moderately-active, middleaged adults showed improved continuous glucose regulation and lower central arterial stiffness following one week of riding an EB.

Aerobic or resistance exercise performed the previous day does not attenuate postprandial hyperglycemia-induced endothelial dysfunction in overweight/obese adults.

INTRODUCTION: Postprandial hyperglycemia (PPH) impairs vascular endothelial function (VEF). A single bout of aerobic exercise (AE) attenuates PPH-induced decreases in brachial artery flow-mediated dilation (FMD), a non-invasive measure of VEF, in healthy adults for up to 17 h post-exercise. Studies examining the effects of resistance exercise (RE) on postprandial FMD responses are lacking. PURPOSE: We hypothesized that a single bout of exercise performed the prior evening would attenuate PPH-induced decreases in FMD, independent of exercise modality. METHODS: In a randomized, cross-over design, overweight/obese adults [n = 11 (8 women); 22 ± 4 years; 32.3 ± 5.8 kg m-2] completed 3 separate trials: control (seated rest), AE (30 min at ~ 60% VO2max), or whole-body RE (30 min, 6 exercises, 3 × 10-repetition maximum). Each trial occurred 14-17 h prior to an oral glucose tolerance test (OGTT). Brachial artery FMD and plasma glucose and insulin were measured prior to and at 30-min intervals for 2 h following the OGTT. Repeated-measures ANOVA and Bonferroni post hoc tests were used to evaluate differences within and between trials. RESULTS: Trials occurred 15.3 ± 1.0 h prior to the OGTT. Relative to baseline, FMD transiently decreased (P < 0.05) at 30-60 min post-ingestion, plasma glucose increased (P < 0.01) at 30-90 min post-ingestion, and plasma insulin increased (P < 0.01) at 30-120 min post-ingestion. No between trial differences were observed for FMD, glucose, or insulin. CONCLUSIONS: Aerobic or resistance exercise performed the evening prior to an OGTT does not attenuate postprandial decreases in brachial artery FMD in overweight/obese adults.

The Influence of Compression Socks During a Marathon on Exercise-Associated Muscle Damage.

CONTEXT: Compression socks have become increasingly popular with athletes due to perceived enhancement of exercise performance and recovery. However, research examining the efficacy of compression socks to reduce exercise-associated muscle damage has been equivocal, with few direct measurements of markers of muscle damage. OBJECTIVE: To examine the influence of compression socks worn during a marathon on creatine kinase (CK) levels. DESIGN: A randomized controlled trial. SETTING: 2013 Hartford Marathon, Hartford, CT. PARTICIPANTS: Adults (n = 20) randomized to control (CONTROL; n = 10) or compression sock (SOCK; n = 10) groups. MAIN OUTCOME MEASURES: Blood samples were collected 24 hours before, immediately after, and 24 hours following the marathon for the analysis of CK, a marker of muscle damage. RESULTS: Baseline CK levels did not differ between CONTROL (89.3 [41.2] U/L) and SOCK (100.0 [56.2] U/L) (P = .63). Immediately following the marathon (≤1 h), CK increased 273% from baseline (P < .001 for time), with no difference in exercise-induced changes in CK from baseline between CONTROL (+293.9 [278.2] U/L) and SOCK (+233.1 [225.3] U/L; P = .60 for time × group). The day following the marathon (≤24 h), CK further increased 1094% from baseline (P < .001 for time), with no difference in changes in CK from baseline between CONTROL (+ 1191.9 [1194.8] U/L) and SOCK (+889.1 [760.2] U/L; P = .53 for time × group). These similar trends persisted despite controlling for potential covariates such as age, body mass index, and race finishing time (Ps > .29). CONCLUSIONS: Compression socks worn during a marathon do not appear to mitigate objectively measured markers of muscle damage immediately following and 24 hours after a marathon.

Comparative Metabolomics Elucidates Postprandial Metabolic Modifications in Plasma of Obese Individuals with Metabolic Syndrome.

Although higher intakes of dairy milk are associated with a lower risk of metabolic syndrome (MetS), the underlying protective mechanism remains unclear. This study investigated the dynamic metabolic profile shift following the ingestion of low-fat milk or an isocaloric volume of rice milk in obese individuals with metabolic syndrome (MetS). In a randomized, double-blind, crossover study, postprandial plasma samples ( n = 266) were collected from 19 MetS participants. Plasma samples were analyzed by a targeted metabolomics platform which specifically detects 117 metabolites from 25 metabolic pathways. The comprehensive time-course metabolic profiling in MetS participants indicated that the postprandial metabolic profiles distinguish low-fat milk and rice milk consumption in a time-dependent manner. Metabolic biomarkers, such as orotate, leucine/isoleucine and adenine, showed significantly different trends in the two test beverages. Bayesian statistics identified 12 metabolites associated with clinical characteristics of postprandial vascular endothelial function, such as flow-mediated dilation (FMD), postprandial plasma markers of oxidative stress and NO status. Furthermore, metabolic pathway analysis based on these metabolite data indicated the potential utility of metabolomics to provide mechanistic insights of dietary interventions to regulate postprandial metabolic excursions.

Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study.

BACKGROUND: Cardiovascular disease (CVD) is a leading cause of death among adults with type 2 diabetes mellitus (T2D). We recently reported that glycemic control in patients with T2D can be significantly improved through a continuous care intervention (CCI) including nutritional ketosis. The purpose of this study was to examine CVD risk factors in this cohort. METHODS: We investigated CVD risk factors in patients with T2D who participated in a 1 year open label, non-randomized, controlled study. The CCI group (n = 262) received treatment from a health coach and medical provider. A usual care (UC) group (n = 87) was independently recruited to track customary T2D progression. Circulating biomarkers of cholesterol metabolism and inflammation, blood pressure (BP), carotid intima media thickness (cIMT), multi-factorial risk scores and medication use were examined. A significance level of P < 0.0019 ensured two-tailed significance at the 5% level when Bonferroni adjusted for multiple comparisons. RESULTS: The CCI group consisted of 262 participants (baseline mean (SD): age 54 (8) year, BMI 40.4 (8.8) kg m-2). Intention-to-treat analysis (% change) revealed the following at 1-year: total LDL-particles (LDL-P) (- 4.9%, P = 0.02), small LDL-P (- 20.8%, P = 1.2 × 10-12), LDL-P size (+ 1.1%, P = 6.0 × 10-10), ApoB (- 1.6%, P = 0.37), ApoA1 (+ 9.8%, P < 10-16), ApoB/ApoA1 ratio (- 9.5%, P = 1.9 × 10-7), triglyceride/HDL-C ratio (- 29.1%, P < 10-16), large VLDL-P (- 38.9%, P = 4.2 × 10-15), and LDL-C (+ 9.9%, P = 4.9 × 10-5). Additional effects were reductions in blood pressure, high sensitivity C-reactive protein, and white blood cell count (all P < 1 × 10-7) while cIMT was unchanged. The 10-year atherosclerotic cardiovascular disease (ASCVD) risk score decreased - 11.9% (P = 4.9 × 10-5). Antihypertensive medication use was discontinued in 11.4% of CCI participants (P = 5.3 × 10-5). The UC group of 87 participants [baseline mean (SD): age 52 (10) year, BMI 36.7 (7.2) kg m-2] showed no significant changes. After adjusting for baseline differences when comparing CCI and UC groups, significant improvements for the CCI group included small LDL-P, ApoA1, triglyceride/HDL-C ratio, HDL-C, hsCRP, and LP-IR score in addition to other biomarkers that were previously reported. The CCI group showed a greater rise in LDL-C. CONCLUSIONS: A continuous care treatment including nutritional ketosis in patients with T2D improved most biomarkers of CVD risk after 1 year. The increase in LDL-cholesterol appeared limited to the large LDL subfraction. LDL particle size increased, total LDL-P and ApoB were unchanged, and inflammation and blood pressure decreased. Trial registration Clinicaltrials.gov: NCT02519309. Registered 10 August 2015.

Replacing carbohydrate during a glucose challenge with the egg white portion or whole eggs protects against postprandial impairments in vascular endothelial function in prediabetic men by limiting increases in glycaemia and lipid peroxidation.

Eggs attenuate postprandial hyperglycaemia (PPH), which transiently impairs vascular endothelial function (VEF). We hypothesised that co-ingestion of a glucose challenge with egg-based meals would protect against glucose-induced impairments in VEF by attenuating PPH and oxidative stress. A randomised, cross-over study was conducted in prediabetic men (n 20) who ingested isoenegertic meals (1674 kJ (400 kcal)) containing 100 g glucose (GLU), or 75 g glucose with 1·5 whole eggs (EGG), seven egg whites (WHITE) or two egg yolks (YOLK). At 30 min intervals for 3 h, brachial artery flow-mediated dilation (FMD), plasma glucose, insulin, cholecystokinin (CCK), lipids (total, LDL- and HDL-cholesterol; TAG), F2-isoprostanes normalised to arachidonic acid (F2-IsoPs/AA), and methylglyoxal were assessed. In GLU, FMD decreased at 30-60 min and returned to baseline levels by 90 min. GLU-mediated decreases in FMD were attenuated at 30-60 min in EGG and WHITE. Compared with GLU, FMDAUC was higher in EGG and WHITE only. Relative to baseline, glucose increased at 30-120 min in GLU and YOLK but only at 30-90 min in EGG and WHITE. GlucoseAUC and insulinAUC were also lower in EGG and WHITE only. However, CCKAUC was higher in EGG and WHITE compared with GLU. Compared with GLU, F2-IsoPs/AAAUC was lower in EGG and WHITE but unaffected by YOLK. Postprandial lipids and methylglyoxal did not differ between treatments. Thus, replacing a portion of a glucose challenge with whole eggs or egg whites, but not yolks, limits postprandial impairments in VEF by attenuating increases in glycaemia and lipid peroxidation.

Compression Socks Worn During Flight and Hemostatic Balance in Boston Marathon Runners on Oral Contraceptives.

OBJECTIVE: To investigate the effect of oral contraceptive (OC) use and compression socks on hemostatic activation in women flying cross-country to and from a marathon. DESIGN: Prospective study. SETTING: 2015 Boston Marathon. PARTICIPANTS: Women were divided into non-OC using (CONTROL; n = 12), OC-using (OC; n = 15), and OC-using plus compression sock (OC + SOCK; n = 14) groups. INTERVENTION: Women in OC + SOCK wore compression socks during flights to and from the marathon. MAIN OUTCOME MEASURES: Venous blood samples were collected within 24 hours of arriving in Boston (EXPO), immediately after the marathon (RUN), and within 24 hours after a return flight home (Post-Flight) for analysis of thrombin-antithrombin complex (TAT), d-dimer, and tissue plasminogen activator (t-PA). RESULTS: TAT did not increase with exercise (P = 0.48) and was not affected by group (P = 0.08) or the interaction between these 2 factors (P = 0.80). Group, time, and their interaction were significant for d-dimer (all P < 0.05) such that d-dimer increased with acute exercise to a greater extent (Δ d-dimer from expo to postrace = 909.5 ± 1021.9 ng/mL) in the OC + SOCK group relative to OC (Δ d-dimer = 240.0 ± 178.5 ng/mL; P = 0.02) and CONTROL (Δ d-dimer = 230.3 ± 120.3 ng/mL; P = 0.02). There was a significant effect of time, group, and the interaction on t-PA (all P < 0.01) such that t-PA increased with acute exercise to a greater extent (Δ t-PA from expo to postrace = 19.6 ± 10.0 ng/mL) in the CONTROL group relative to OC (Δ t-PA = 4.0 ± 1.8 ng/mL; P < 0.01) and OC + SOCK (Δ t-PA = 3.3 ± 1.2 ng/mL; P < 0.01). CONCLUSIONS: Female runners using OCs did not exhibit disproportionately increased coagulation. The use of compression socks in women on OCs, surprisingly, resulted in a greater increase in d-dimer after exercise.

Altering Physical Activity Influences Insulin Responses to Glucose Ingestion in Healthy Adults.

This study determined if varying physical activity (PA) the day prior to an oral glucose tolerance test (OGTT) differentially influenced postprandial glucose and insulin kinetics. Fifteen healthy, young adults participated in three OGTT trials the morning after performing 50% (LOW), 100% (HABITUAL), or 150% (HIGH) of their habitual PA (determined by 7-day pedometry). Trials were randomized and separated by at least 1-wk. For each OGTT trial, blood glucose and insulin were measured after an overnight fast and at 30-min intervals for 2 h following ingestion of the glucose beverage. Between-trial differences were analyzed using a general linear model with repeated measures. Subjects successfully achieved the desired percentage of habitual steps prior to each trial: LOW: 51±5%, HABITUAL: 99±6%, and HIGH: 149±9%. Fasting blood glucose and glucose total area under the curve (AUC) did not differ between trials. Serum insulin AUC was lower (p<0.05) following the HIGH (34,158±8,786 pmol·min·L-1) compared to the LOW (40,738±9,276 pmol·min·L-1) trial. No differences were observed when the LOW and HIGH trials were compared to HABITUAL. These data suggest that varying the PA level (from 50 to 150% of habitual PA) the day prior to an OGTT influences the insulin (but not blood glucose) response to an OGTT.

Effects of prior aerobic exercise on sitting-induced vascular dysfunction in healthy men.

INTRODUCTION: Acute aerobic exercise prevents sitting-induced impairment of flow-mediated dilation (FMD). Further, evidence suggests that sitting-induced impairment of FMD occurs via an oxidative stress-dependent mechanism that disrupts endothelial function. PURPOSE: We hypothesized that acute aerobic exercise would prevent impairment of femoral artery FMD by limiting oxidative stress responses that increase endothelin-1 (ET-1) levels and disrupt nitric oxide (NO) status. METHODS: In a randomized, cross-over study, healthy men (n = 11; 21.2 ± 1.9 years) completed two 3 h sitting trials that were preceded by 45 min of either quiet rest (REST) or a single bout of continuous treadmill exercise (65% maximal oxygen consumption) (EX). Superficial femoral artery FMD, plasma glucose, malondialdehyde (MDA), ET-1, arginine (ARG) and its related metabolites [homoarginine (HA), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA)] were assessed at baseline, 1 h following EX (or REST) (0 h), and at 1 h intervals during 3 h of uninterrupted sitting. Data were analyzed using repeated measures ANOVA. RESULTS: During REST, femoral artery FMD declined from baseline (2.6 ± 1.8%) at 1, 2, and 3 h of sitting and resting shear rate decreased at 3 h. In contrast, when sitting was preceded by EX, femoral artery FMD (2.7 ± 2.0%) and resting shear rate responses were unaffected. No between trial differences were detected for plasma glucose, MDA, ET-1, ARG, HA, ADMA, or SDMA. CONCLUSION: Prior aerobic exercise prevented the decline in femoral artery FMD that is otherwise induced by prolonged sitting independent of changes in oxidative stress, ET-1, and NO status.

Effect of cycling in the heat for 164 km on procoagulant and fibrinolytic parameters.

PURPOSE: We assessed the impact of completing the Hotter'n Hell Hundred (HHH), an annual 164 km road cycling event performed in a hot environment, on hemostatic balance in men. METHODS: Sixteen men who completed the ride in <6 h were included in this study. Plasma samples were collected on that morning of the ride (PRE) and immediately on the completion of the ride (IP). Primary hemostasis was assessed by platelet count and von Willebrand factor antigen (vWF:Ag). Coagulation was assessed by measuring prothrombin fragment 1 + 2 (PTF 1 + 2) and thrombin-antithrombin complex (TAT), whereas fibrinolysis was assessed by plasminogen activator inhibitor antigen (PAI-1 Ag), tissue plasminogen activator (tPA Ag), and D-Dimer analyses. RESULTS: Compared to PRE, increases (p < 0.001) were observed at IP for platelets (39 %), vWF:Ag (65 %), PTF 1 + 2 (47 %), TAT (81 %), tPA Ag (231 %), PAI-1 Ag (148 %), and D-Dimer (54 %). PRE PAI-1 Ag concentrations were directly related to BMI and waist circumference (p < 0.05). D-Dimer concentrations at IP correlated positively with age (p < 0.05). CONCLUSIONS: Completing the HHH activated the coagulation and fibrinolytic systems in balance. Age was positively correlated with IP D-Dimer concentrations. Additionally, participants displaying a larger BMI and waist circumference exhibited a positive correlation with PRE PAI-1 Ag concentrations.

Habitual exercise may maintain endothelium-dependent dilation in overweight postmenopausal women.

Compared with their physically active peers, overweight sedentary postmenopausal women demonstrate impaired vascular endothelial function (VEF), substantially increasing the risk for cardiovascular disease (CVD). Habitual exercise is associated with improved VEF and reduced CVD risk. The purpose of this study was to compare brachial artery flow mediated dilation (FMD), a measure of VEF, in overweight, postmenopausal women who were physically active (EX: n = 17, BMI: 29.3 ± 3.11 kg/m2) or sedentary (CON: n = 8, BMI: 30.3 ± 3.6 kg/m2). Anthropomorphic measures were similar in both groups (P > .05). FMD was significantly greater in EX (10.24 ± 2.36%) versus CON (6.60 ± 2.18%) (P < .002). FMD was not significantly correlated with estimated VO2max (EX: r = .17, P = .52; CON: r = .20, P = .60) but was negatively associated with percent body fat in EX group (EX: r = -.48, P = .05; CON: r = .41, P = .31). These results are consistent with the positive effects of habitual exercise on VEF in overweight postmenopausal women.

Low-fat milk ingestion prevents postprandial hyperglycemia-mediated impairments in vascular endothelial function in obese individuals with metabolic syndrome.

Greater intakes of low-fat dairy foods are associated with a lower risk of cardiovascular disease. The objective of this study was to examine whether acute low-fat milk ingestion would limit postprandial impairments in vascular endothelial function by limiting oxidative stress responses that decrease nitric oxide (NO) bioavailability. A randomized, double-blind, cross-over study was conducted in adults with metabolic syndrome (MetS) who ingested low-fat milk (475 mL) or an isocaloric volume of rice milk after an overnight fast. Brachial artery flow-mediated dilation (FMD), plasma glucose, malondialdehyde (MDA), arginine (ARG), and asymmetric dimethylarginine (ADMA) were assessed at 30-min intervals during the 3-h postprandial period. Participants' (n = 19) postprandial FMD responses were unaffected by low-fat milk but transiently decreased (P < 0.01) from 6.2 ± 0.8% (mean ± SEM) at baseline to 3.3 ± 0.7% at 30 min and 3.9 ± 0.6% at 60 min following rice milk consumption. Glucose and MDA increased to a greater extent in the rice milk trial (P < 0.001). The MDA area under the 3 h postprandial curve (AUC0-3 h) was correlated with glucose AUC0-3 h (r = 0.75; P < 0.01) and inversely related to FMD AUC0-3 h (r = -0.59; P < 0.01). ARG decreased following rice milk and increased with low-fat milk, whereas only rice milk increased ADMA:ARG. The ADMA:ARG AUC0-3 h was correlated with MDA AUC0-3 h (r = 0.55) and was inversely related to FMD AUC0-3 h (r = -0.52) (P < 0.05). These findings suggest that low-fat milk maintains vascular endothelial function in individuals with MetS by limiting postprandial hyperglycemia that otherwise increases lipid peroxidation and reduces NO bioavailability. This trial was registered at clinicaltrials.gov as NCT01411293.

Whey protein supplementation during resistance training augments lean body mass.

UNLABELLED: Compared to soy, whey protein is higher in leucine, absorbed quicker and results in a more pronounced increase in muscle protein synthesis. OBJECTIVE: To determine whether supplementation with whey promotes greater increases in muscle mass compared to soy or carbohydrate, we randomized non-resistance-trained men and women into groups who consumed daily isocaloric supplements containing carbohydrate (carb; n = 22), whey protein (whey; n = 19), or soy protein (soy; n = 22). METHODS: All subjects completed a supervised, whole-body periodized resistance training program consisting of 96 workouts (~9 months). Body composition was determined at baseline and after 3, 6, and 9 months. Plasma amino acid responses to resistance exercise followed by supplement ingestion were determined at baseline and 9 months. RESULTS: Daily protein intake (including the supplement) for carb, whey, and soy was 1.1, 1.4, and 1.4 g·kg body mass⁻¹, respectively. Lean body mass gains were significantly (p < 0.05) greater in whey (3.3 ± 1.5 kg) than carb (2.3 ± 1.7 kg) and soy (1.8 ± 1.6 kg). Fat mass decreased slightly but there were no differences between groups. Fasting concentrations of leucine were significantly elevated (20%) and postexercise plasma leucine increased more than 2-fold in whey. Fasting leucine concentrations were positively correlated with lean body mass responses. CONCLUSIONS: Despite consuming similar calories and protein during resistance training, daily supplementation with whey was more effective than soy protein or isocaloric carbohydrate control treatment conditions in promoting gains in lean body mass. These results highlight the importance of protein quality as an important determinant of lean body mass responses to resistance training.

Acute effects of ingestion of a novel whey-derived extract on vascular endothelial function in overweight, middle-aged men and women.

Whey protein intake reduces CVD risk, but little is known whether whey-derived bioactive peptides regulate vascular endothelial function (VEF). We determined the impact of a whey-derived extract (NOP-47) on VEF in individuals with an increased cardiovascular risk profile. Men and women with impaired brachial artery flow-mediated dilation (FMD) (n 21, age 55 (sem 1·3) years, BMI 27·8 (sem 0·6) kg/m2, FMD 3·7 (sem 0·4) %) completed a randomised, cross-over study to examine whether ingestion of NOP-47 (5 g) improves postprandial VEF. Brachial artery FMD, plasma amino acids, insulin, and endothelium-derived vasodilators and vasoconstrictors were measured for 2 h after ingestion of NOP-47 or placebo. Acute NOP-47 ingestion increased FMD at 30 min (4·6 (sem 0·5) %) and 120 min (5·1 (sem 0·5) %) post-ingestion (P< 0·05, time × trial interaction), and FMD responses at 120 min were significantly greater in the NOP-47 trial compared with placebo (4·3 (sem 0·5) %). Plasma amino acids increased at 30 min following NOP-47 ingestion (P< 0·05). Serum insulin increased at 15, 30 and 60 min (P< 0·001) following NOP-47 ingestion. No changes were observed between the trials for plasma NO∙ and prostacyclin metabolites or endothelin-1. Ingestion of a rapidly absorbed extract derived from whey protein improved endothelium-dependent dilation in older adults by a mechanism independent of changes in circulating vasoactive compounds. Future investigation is warranted in individuals at an increased CVD risk to further elucidate potential health benefits and the underlying mechanisms of extracts derived from whey.

Postprandial hyperglycemia impairs vascular endothelial function in healthy men by inducing lipid peroxidation and increasing asymmetric dimethylarginine:arginine.

Postprandial hyperglycemia induces vascular endothelial dysfunction (VED) and increases future cardiovascular disease risk. We hypothesized that postprandial hyperglycemia would decrease vascular function in healthy men by inducing oxidative stress and proinflammatory responses and increasing asymmetric dimethylarginine:arginine (ADMA:arginine), a biomarker that is predictive of reduced NO biosynthesis. In a randomized, cross-over design, healthy men (n = 16; 21.6 ± 0.8 y) ingested glucose or fructose (75 g) after an overnight fast. Brachial artery flow-mediated dilation (FMD), plasma glucose and insulin, antioxidants, malondialdehyde (MDA), inflammatory proteins, arginine, and ADMA were measured at regular intervals during the 3-h postprandial period. Baseline FMD did not differ between trials (P > 0.05). Postprandial FMD was reduced following the ingestion of glucose only. Postprandial MDA concentrations increased to a greater extent following the ingestion of glucose compared to fructose. Plasma arginine decreased and the ratio of ADMA:arginine increased to a greater extent following the ingestion of glucose. Inflammatory cytokines and cellular adhesion molecules were unaffected by the ingestion of either sugar. Postprandial AUC(0-3 h) for FMD and MDA were inversely related (r = -0.80; P < 0.05), suggesting that hyperglycemia-induced lipid peroxidation suppresses postprandial vascular function. Collectively, these findings suggest that postprandial hyperglycemia in healthy men reduces endothelium-dependent vasodilation by increasing lipid peroxidation independent of inflammation. Postprandial alterations in arginine and ADMA:arginine also suggest that acute hyperglycemia may induce VED by decreasing NO bioavailability through an oxidative stress-dependent mechanism. Additional work is warranted to define whether inhibiting lipid peroxidation and restoring arginine metabolism would mitigate hyperglycemia-mediated decreases in vascular function.

A multi-nutrient supplement reduced markers of inflammation and improved physical performance in active individuals of middle to older age: a randomized, double-blind, placebo-controlled study.

BACKGROUND: While exercise acts to combat inflammation and aging, the ability to exercise may itself be compromised by inflammation and inflammation's impact on muscle recovery and joint inflammation. A number of nutritional supplements have been shown to reduce inflammation and improve recovery. The purpose of the current investigation was to examine the effect of a multi-nutrient supplement containing branched chain amino acids, taurine, anti-inflammatory plant extracts, and B vitamins on inflammatory status, endothelial function, physical function, and mood in middle-aged individuals. METHODS: Thirty-one healthy and active men (N = 16, mean age 56 ± 6.0 yrs) and women (N = 15, mean age = 52 ± 7.5 yrs) participated in this investigation. Subjects completed one 28 day cycle of placebo supplementation and one 28 day cycle of multi-nutrient supplementation (separated by a one week washout period) in a balanced, randomized, double-blind, cross-over design. Subjects completed weekly perceptual logs (PROMIS-57, KOOS) and pre- and post- testing around the supplementation period. Testing consisted of brachial artery flow mediated dilation (FMD), blood measures, and physical performance on vertical jump, handgrip strength, and balance (dispersion from center of pressure). Significance for the investigation was p ≤ 0.05. RESULTS: IL-6 significantly decreased in both men (from 1.2 ± 0.2 to 0.7 ± 0.4 pg·mL(-1)) and women (from 1.16 ± 0.04 to 0.7 ± 0.4 pg·mL(-1)). Perceived energy also improved for both men (placebo: 1.8 ± 0.7; supplement: 3.7 ± 0.8 AUC) and women (placebo: 1.2 ± 0.7; supplement: 2.8 ± 0.8 AUC). Alpha-1-antichymotrypsin (from 108.9 ± 38.6 to 55.5 ± 22.2 ug·mL(-1)), Creatine Kinase (from 96 ± 34 to 67 ± 23 IU·L(-1)), general pain, and joint pain decreased in men only, while anxiety and balance (from 0.52 ± 0.13 to 0.45 ± 0.12 cm) improved in women only. Men showed increased performance in vertical jump power (from 2642 ± 244 to 3134 ± 282 W) and grip strength (from 42.1 ± 5.9 to 48.5 ± 4.9 kg). CONCLUSIONS: A multi-nutrient supplement is effective in improving inflammatory status in both men and women, markers of pain, joint pain, strength, and power in men only, and both anxiety and balance (a risk factor for hip fracture) in women. Therefore, a multi-nutrient supplement may help middle-aged individuals to prolong physical function and maintain a healthy, active lifestyle.

Influence of time of day and intermittent aerobic exercise on vascular endothelial function and plasma endothelin-1 in healthy adults.

Reduced flow-mediated dilation (FMD) and elevated plasma endothelin-1 (ET-1) levels may contribute to the higher incidence of adverse cardiovascular events observed in the morning hours. A single bout of intermittent exercise abolishes the diurnal variation in FMD. Studies examining the effects of exercise on vascular and plasma ET-1 responses at different times of day are lacking. We determined the effects of time of day and intermittent aerobic exercise on brachial artery FMD and plasma ET-1 levels in healthy adults. We hypothesized that lower brachial artery FMD in the morning (compared to the afternoon) will be accompanied by higher plasma ET-1 levels. Additionally, we hypothesized that the diurnal variation in brachial artery FMD and plasma ET-1 will be abolished by performing a single bout of intermittent aerobic exercise. Utilizing a randomized, cross-over design, healthy adults [n = 12; 22 ± 4 y; 25.2 ± 2.7 kg/m2] completed two separate trials: morning (08:00 h) and afternoon (16:00 h). Brachial artery FMD and plasma ET-1 were measured prior to and immediately following a bout of intermittent cycling performed at 70% peak Watts. Brachial artery FMD was lower (P < .05) at 08:00 h (4.4 ± 3.4%) compared to 16:00 h (6.3 ± 3.7%), but was unaffected by exercise (4.8 ± 3.9% and 5.7 ± 2.2% for 08:00 h and 16:00 h, respectively). Plasma ET-1 was unaffected by time of day. Compared to pre-exercise, plasma ET-1 decreased (P < .01) at both times of day. Our data indicate that circulating ET-1 levels do not explain the lower morning FMD in healthy adults. Further, a bout of intermittent exercise did not affect brachial artery FMD but decreased plasma ET-1 levels.

Effect of quercetin supplementation on maximal oxygen uptake in men and women.

Quercetin is a naturally occurring flavonoid with anti-oxidant and anti-inflammatory properties. The effect of quercetin supplementation on maximal oxygen uptake (VO(2max)) is unknown. The purpose of this investigation was to test the effects of quercetin supplementation on VO(2max) in untrained, sedentary individuals. After baseline treadmill VO(2max) testing, 11 participants (5 males, 6 females) ingested either placebo or quercetin-supplemented (1000 mg x day(-1)) food bars in a randomized, double-blind, counterbalanced, crossover research design. The participants ingested food bars for six consecutive mornings (5 days). On the sixth morning, participants underwent repeat VO(2max) testing. After a 22 day wash-out, the participants repeated baseline VO(2max) testing, daily consumption of the opposite food bars, and post-supplementation VO(2max) testing. The condition x time interaction for VO(2max) was non-significant when expressed in absolute (litres x min(-1); P = 0.929) and relative (ml x kg(-1) x min(-1); P = 0.778) terms. These findings were similar when taking sex into account (P > 0.05). The mean difference in VO(2max) change from pre to post between groups (quercetin vs. placebo) was 0.139 ml x kg(-1) x min(-1) (P = 0.780). Other physiological measures also were similar between conditions (P > 0.05). In conclusion, 5 days of quercetin supplementation did not influence VO(2max) or related variables in sedentary men and women.

Associations Among Physical Activity Level and Skeletal Muscle Antioxidants in Older Adults.

BACKGROUND: Endogenous antioxidants are critical to limiting cellular oxidative damage. METHODS: The authors determined if habitual physical activity (PA) and cardiorespiratory fitness were associated with skeletal muscle expression of endogenous antioxidants (superoxide dismutase, catalase, and glutathione peroxidase) and circulating oxidative stress markers (serum 8-hydroxy-2'-deoxyguanosine [8-OHdG]; oxidized low-density lipoprotein [LDL]) in older adults. Moderate to vigorous PA (MVPA) was estimated using a validated PA questionnaire in 26 older adults (mean [SD]; M/F = 9/17, age = 68 [4] y, body mass index = 26 [3] kg·m-2). Maximal oxygen consumption was estimated using the YMCA submaximal cycle test. Skeletal muscle endogenous antioxidants and serum 8-OHdG and oxidized LDL were measured. Bivariate and partial correlations (controlling for body mass index) were utilized to determine associations among variables. RESULTS: MVPA (1640 [1176] kcal·wk-1) was correlated with superoxide dismutase 2 (r = .55), catalase (r = .55), glutathione peroxidase 1 (r = .48), and 8-OHdG (r = -.41) (all Ps < .05), but not oxidized LDL. MVPA and 8-OHdG were not significantly correlated when controlling for body mass index (r = -.29). Estimated maximal oxygen consumption was correlated with glutathione peroxidase 1 (r = .48; P < .05). CONCLUSIONS: These data show that skeletal muscle endogenous antioxidant expression and circulating oxidative damage are associated with habitual MVPA in older adults. Thus, MVPA in older adults may be protective against reactive oxygen species damage due to higher expression of endogenous antioxidants.

Acute ingestion of a novel whey-derived peptide improves vascular endothelial responses in healthy individuals: a randomized, placebo controlled trial.

BACKGROUND: Whey protein is a potential source of bioactive peptides. Based on findings from in vitro experiments indicating a novel whey derived peptide (NOP-47) increased endothelial nitric oxide synthesis, we tested its effects on vascular function in humans. METHODS: A randomized, placebo-controlled, crossover study design was used. Healthy men (n = 10) and women (n = 10) (25 +/- 5 y, BMI = 24.3 +/- 2.3 kg/m2) participated in two vascular testing days each preceded by 2 wk of supplementation with a single dose of 5 g/day of a novel whey-derived peptide (NOP-47) or placebo. There was a 2 wk washout period between trials. After 2 wk of supplementation, vascular function in the forearm and circulating oxidative stress and inflammatory related biomarkers were measured serially for 2 h after ingestion of 5 g of NOP-47 or placebo. Macrovascular and microvascular function were assessed using brachial artery flow mediated dilation (FMD) and venous occlusion strain gauge plethysmography. RESULTS: Baseline peak FMD was not different for Placebo (7.7%) and NOP-47 (7.8%). Placebo had no effect on FMD at 30, 60, and 90 min post-ingestion (7.5%, 7.2%, and 7.6%, respectively) whereas NOP-47 significantly improved FMD responses at these respective postprandial time points compared to baseline (8.9%, 9.9%, and 9.0%; P < 0.0001 for time x trial interaction). Baseline reactive hyperemia forearm blood flow was not different for placebo (27.2 +/- 7.2%/min) and NOP-47 (27.3 +/- 7.6%/min). Hyperemia blood flow measured 120 min post-ingestion (27.2 +/- 7.8%/min) was unaffected by placebo whereas NOP-47 significantly increased hyperemia compared to baseline (29.9 +/- 7.8%/min; P = 0.008 for time x trial interaction). Plasma myeloperoxidase was increased transiently by both NOP-47 and placebo, but there were no changes in markers inflammation. Plasma total nitrites/nitrates significantly decreased over the 2 hr post-ingestion period and were lower at 120 min after placebo (-25%) compared to NOP-47 (-18%). CONCLUSION: These findings indicate that supplementation with a novel whey-derived peptide in healthy individuals improves vascular function.