Effects of plant- and animal-based-protein meals for a day on serum nitric oxide and peroxynitrite levels in healthy young men.

Plant-based diets that replace animal-based proteins with plant-based proteins have received increased attention for cardiovascular protection. Nitric oxide (NO) plays an essential role in the maintenance of endothelial function. However, under higher oxidative stress, NO generation produces peroxynitrite, a powerful oxidant and vasoconstrictor. Diet-replaced protein sources has been reported to decrease oxidative stress. However, the effects of plant-based protein on NO and peroxynitrite have not yet been clarified. Therefore, this study aimed to compare the effects of plant- and animal-based-protein meals for a day on NO, peroxynitrite, and NO/peroxynitrite balance. A crossover trial of two meal conditions involving nine healthy men was performed. Participants ate standard meals during day 1. On day 2, baseline measurements were performed and the participants were provided with plant-based-protein meals or animal-based-protein meals. The standard and test meals consisted of breakfast, lunch, and dinner and were designed to be isocaloric. Plant-based-protein meals contained no animal protein. Blood samples were collected in the morning after overnight fasting before and after the test meals consumption. In the plant-based-protein meal condition, serum NOx levels (the sum of serum nitrite and nitrate) significantly increased, while serum peroxynitrite levels did not change significantly. Animal-based-protein meals significantly increased serum peroxynitrite levels but showed a trend of reduction in the serum NOx levels. Furthermore, serum NO/peroxynitrite balance significantly increased after plant-based-protein meals consumption, but significantly decreased after animal-based-protein meals consumption. These results suggest that, compared with animal-based-protein meals, plant-based-protein meals increase NO levels and NO/peroxynitrite balance, which reflects increased endothelial function.

Association between the intake of plant and animal proteins and the serum fibroblast growth factor-23 level in patients with chronic kidney disease analyzed by the isocaloric substitution model.

Fibroblast growth factor-23 (FGF23) is a phosphaturic hormone secreted by the bone in response to dietary phosphate intake. Since the phosphate content in the diet correlates with the protein content, both plant- and animal-based protein intake can increase the serum FGF23 level. However, a higher percentage of energy from plant protein than from animal protein is associated with a lower serum FGF23 level in patients with chronic kidney disease (CKD) in the United States. Since dietary habits differ between Asian and Western populations, we performed a cross-sectional study to determine the association between the percentages of energy from plant and animal proteins and the serum FGF23 level in Japanese CKD patients. In 107 non-dialysis CKD patients (age: 66 ± 9 years; estimated glomerular filtration rate: 56 ± 21 mL/min/1.73 m2), the percentages of energy from plant and animal proteins were assessed using a food frequency questionnaire based on food groups. Venous blood samples were used to measure the serum FGF23, phosphate, 1,25-dihydroxyvitamin D, and intact parathyroid hormone levels. The percentages of energy from plant and animal proteins showed a negative and positive association, respectively, with the serum FGF23 level. Furthermore, isocaloric substitution modeling showed that replacing animal protein with plant protein was associated with a low serum FGF23 level. Our findings suggest that encouraging diets with high plant protein level may prevent an increase in the serum FGF23 level in Japanese CKD patients.

Summary of the clinical practice manual for late-onset hypogonadism.

Testosterone plays an important role in maintaining both physical and mental function. Age-related testosterone depletion contributes to the development of angina, arteriosclerosis, obesity, metabolic syndrome, dementia, frailty, and a range of other conditions. A condition involving age-related testosterone depletion and the associated clinical symptoms is defined as late-onset hypogonadism (LOH). LOH is treated by testosterone replacement therapy. Indications for testosterone replacement therapy are determined by evaluating symptoms and signs.

Effects of Changes in Body Fat Mass as a Result of Regular Exercise on Hemoglobin A1c in Patients With Type 2 Diabetes Mellitus: A Meta-Analysis.

An increase in visceral fat is associated with an increase in insulin resistance, so reducing body fat mass through exercise may help alleviate type 2 diabetes mellitus (T2DM). The current meta-analysis evaluated the effect of changes in body fat via an intervention of regular exercise on hemoglobin A1c (HbA1c) in patients with T2DM. The inclusion criteria were randomized controlled trials involving adults with T2DM, intervention involving exercise alone, an overall duration of intervention ≥12 weeks, and reporting HbA1c and body fat mass. The mean differences (MDs) were defined as the MD between the exercise group and the control group, and the MDs in HbA1c (in percentage) and body fat mass (in kilograms) were calculated. All MDs in HbA1c were pooled as overall effects. A meta-regression analysis was performed to evaluate the relationship between the MD in the body fat mass (in kilograms) and the MD in HbA1c. Twenty studies (1,134 subjects) were analyzed. The pooled MD in HbA1c (in percentage) decreased significantly (-0.4; 95% confidence interval [-0.5, -0.3]) but contained significant heterogeneity (Q = 52.7, p < .01; I2 = 41.6%). A meta-regression analysis showed that a decrease in the MD in body fat mass was significantly associated with a decrease in the MD in HbA1c (R2 = 80.0%) and heterogeneity decreased (Q = 27.3, p = .61; I2 = 11.9%), and a reduction in body fat mass of 1 kg was estimated to decrease the HbA1c (%) by approximately 0.2. The current study suggested that a decrease in HbA1c due to regular exercise depends on a reduction in body fat mass in patients with T2DM.

Body height determines carotid stiffness following resistance exercise in young Japanese men.

Height is inversely associated with an increase in arterial stiffness after habitual resistance exercise (RE). Considering that RE is performed during exercise prescriptions, the association between height and the acute effects of RE on arterial stiffness should be clarified. We investigated the effects of height on arterial stiffness following transient RE. Thirty-nine young Japanese men were studied under parallel experimental conditions [sham control (seated rest) and RE (5 sets of 10 repetitions at 75% of one-repetition maximum)], which were randomly ordered on two separate days. The subjects were divided into tertiles of height (each group, n = 13). The ß-stiffness index (index of arterial stiffness), assessed by carotid pulse pressure and distension, was measured in all subjects. A significant interaction between time, height, and RE was found for the ß-stiffness index (P = 0.01). RE significantly increased the ß-stiffness index in the lower-height group (P < 0.001), but not in the middle- and higher-height groups. Height was negatively associated with an increase in ß-stiffness index following RE, even after controlling the confounders, including exercise volume and changes in heart rate and carotid pulse pressure (P = 0.003). The mediation analysis demonstrated a mediating effect of carotid distension on the relationship between height and changes in the ß-stiffness index. These results suggest that short height individuals have increased arterial stiffness following RE due to decreased mechanical distension, rather than through the widening of pulsatile pressure.

Effects of the number of sit-stand maneuver repetitions on baroreflex sensitivity and cardiovascular risk assessments.

Sit-stand maneuvers (SSMs) have increasingly been used for baroreflex sensitivity (BRS) measurement in physiological research, but it remains unknown as to how many SSMs need to be performed to measure BRS and assess its relationship with cardiovascular disease (CVD) risk. Therefore, this study aimed to determine 1) the effect of the number of SSM repetitions on BRS, and 2) the association between BRS and CVD risk factors. Data were collected from 174 individuals during 5 min of spontaneous rest and 5 min of repeated SSMs at 0.05 Hz (i.e., 15 cycles of 10-s sit and 10-s stand). During SSMs, BRS was calculated from the incremental cycles of 3, 6, 9, 12, and 15 SSMs using transfer function analysis of heart rate (HR) and systolic blood pressure (SBP). General CVD risk factors, carotid arterial stiffness, and cardiorespiratory fitness were measured. In result, HR and SBP increased during SSMs (P < 0.05). The BRS remained at a similar level during the resting and SSM conditions, whereas the coherence function reached its peak after 3 cycles of SSMs. BRS with ≥6 cycles of SSMs was strongly correlated with age (r = -0.721 to -0.740), carotid distensibility (r = 0.625-0.629), and cardiorespiratory fitness (r = 0.333-0.351) (all P < 0.001). Multiple regression analysis demonstrated that BRS with ≥6 cycles of SSMs explained >60% of the variance in CVD risk factors. Therefore, our findings suggest that repeated SSMs significantly strengthens the association between BRS and CVD risk factors. Particularly, BRS with ≥6 cycles of SSMs is strongly associated with CVD risk.

Associations of circulating xanthine oxidoreductase activity with cardiometabolic risk markers in overweight and obese Japanese men: a cross-sectional pilot study.

Circulating xanthine oxidoreductase (XOR) activity may contribute to the pathogenesis of obesity-related adverse cardiometabolic profiles. This pilot study aimed to examine the cross-sectional associations between plasma XOR activity and cardiometabolic risk (CMR) markers in overweight and obese men. In 64 overweight and obese Japanese men (aged 31-63 years), plasma XOR activity and several CMR markers, such as homeostasis model assessment of insulin resistance (HOMA-IR), and clustered CMR score were measured in each participant. Clustered CMR score was constructed based on waist circumference, triglyceride, blood pressure, fasting plasma glucose, and high-density lipoprotein cholesterol. Plasma XOR activity in overweight and obese men was positively associated with the body mass index, waist circumference, visceral fat area, body fat mass, hemoglobin A1c, serum 8-hydroxy-2'-deoxyguanosine, HOMA-IR, and clustered CMR score and was inversely associated with handgrip strength and high-density lipoprotein cholesterol. Multiple linear regression analysis further demonstrated that the associations of plasma XOR activity with HOMA-IR and the clustered CMR score remained significant after adjustment for covariates including uric acid. Our data demonstrate that circulating XOR activity was independently associated, albeit modestly, with HOMA-IR and the clustered CMR score. These preliminary findings suggest that circulating XOR activity can potentially be one of the preventive targets and biomarkers of cardiometabolic disorders in over-weight and obese men.

Changes in hamstring flexibility and muscle strength during the menstrual cycle in healthy young females.

[Purpose] The purpose of this study was to elucidate changes in flexibility and muscle strength during the menstrual cycle in detail and to investigate the relationship between flexibility and muscle strength. [Participants and Methods] Sixteen healthy young female and eight male participants were measured during the follicular, ovulation and luteal phases. Range of motion, passive torque at the onset of pain, passive stiffness and muscle strength were measured using an isokinetic dynamometer. Additionally, electromyography was measured during muscle strength measurement. [Results] In the female group, range of motion and passive torque at the onset of pain were significantly increased during the ovulatory and luteal phases compared with the follicular phase. Passive stiffness decreased significantly during the ovulatory phase compared with the follicular phase. Isometric muscle force and electromyographic activity were significantly increased during the luteal phase compared with the ovulation phase. There was no correlation between stiffness and muscle strength. However, there was a positive correlation between electromyographic activity and muscle strength. [Conclusion] Our findings suggest that changes in flexibility during the ovulatory and luteal phases are influenced by fluctuations in sex hormones. However, the changes in muscle strength showed little relation to flexibility, suggesting the involvement of neural mechanisms.

MOTS-c reduces myostatin and muscle atrophy signaling.

Obesity and type 2 diabetes are metabolic diseases, often associated with sarcopenia and muscle dysfunction. MOTS-c, a mitochondrial-derived peptide, acts as a systemic hormone and has been implicated in metabolic homeostasis. Although MOTS-c improves insulin sensitivity in skeletal muscle, whether MOTS-c impacts muscle atrophy is not known. Myostatin is a negative regulator of skeletal muscle mass and also one of the possible mediators of insulin resistance-induced skeletal muscle wasting. Interestingly, we found that plasma MOTS-c levels are inversely correlated with myostatin levels in human subjects. We further demonstrated that MOTS-c prevents palmitic acid-induced atrophy in differentiated C2C12 myotubes, whereas MOTS-c administration decreased myostatin levels in plasma in diet-induced obese mice. By elevating AKT phosphorylation, MOTS-c inhibits the activity of an upstream transcription factor for myostatin and other muscle wasting genes, FOXO1. MOTS-c increases mTORC2 and inhibits PTEN activity, which modulates AKT phosphorylation. Further upstream, MOTS-c increases CK2 activity, which leads to PTEN inhibition. These results suggest that through inhibition of myostatin, MOTS-c could be a potential therapy for insulin resistance-induced skeletal muscle atrophy as well as other muscle wasting phenotypes including sarcopenia.NEW & NOTEWORTHY MOTS-c, a mitochondrial-derived peptide reduces high-fat-diet-induced muscle atrophy signaling by reducing myostatin expression. The CK2-PTEN-mTORC2-AKT-FOXO1 pathways play key roles in MOTS-c action on myostatin expression.

Replacing sedentary time for physical activity on bone density in patients with chronic kidney disease.

INTRODUCTION: This study aimed to examine the cross-sectional associations of sedentary time and physical activity time with bone density in patients with chronic kidney disease (CKD). The isotemporal substitution (IS) modeling was used to estimate the beneficial effects of behavioral changes (e.g., replacing sedentary time with physical activity time) on bone density in these patients. MATERIALS AND METHODS: A total of 92 patients with CKD (age: 65 ± 9 years; estimated glomerular filtration rate: 57 ± 22 mL/min/1.73 m2) were included in this cross-sectional study. The times spent in sedentary behavior (SB), light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) were assessed using a triaxial accelerometer. Through quantitative ultrasound measurements, the stiffness index, as a measure of bone density, was calculated using the speed of sound and broadband ultrasound attenuation. RESULTS: In multivariate analyses, the stiffness index was beneficially associated with the MVPA time (ß = 0.748), but was not significantly associated with the SB and LPA times. The IS models showed that replacing 10 min/day of SB with the equivalent LPA time was not significantly associated with the stiffness index; however, replacing 10 min/day of SB with the equivalent MVPA time was beneficially associated with the stiffness index (ß = 0.804). CONCLUSION: These results suggest that a small increase in MVPA time (e.g., 10 min/day) may attenuate the decline in bone density in patients with CKD. Our findings may provide insight for the development of novel strategies for improving bone health in patients with CKD.

Regular aerobic exercise improves sexual function assessed by the Aging Males' Symptoms questionnaire in adult men.

The leading cause of aging-induced male-specific disorders such as physical, mental and/or sexual symptoms is testosterone deficiency. Although aerobic exercise is suggested to improves circulating testosterone levels, physical fitness, depressive symptoms, and sexual function, the effect of regular aerobic exercise on aging-induced disorders has not yet been clarified. Here we performed cross-sectional and interventional studies to identify the effect of aerobic exercise on aging-induced disorders assessed by the Aging Males' Symptoms questionnaire (AMS). In study 1, the relationship between aerobic exercise capacity (i.e. peak oxygen consumption) and AMS scores were cross-sectionally examined in 169 adult men. In study 2, the effect of a 12-week regular aerobic exercise on AMS scores was longitudinally investigated in 18 adult men. In study 1, the AMS-total, AMS-somatic, AMS-psychological, and AMS-sexual scores were significantly correlated to aerobic exercise capacity even after considering age and testosterone levels. In study 2, 12-week aerobic exercise training significantly improved AMS-sexual and tended to improve AMS-total scores. Additionally, an increase in vigorous physical activity was correlated to improve in the AMS-sexual score. These results suggest that regular aerobic exercise is an effective strategy to improve aging-induced disorders in men.

Incremental short maximal exercise increases urinary liver-type fatty acid-binding protein in adults without CKD.

Exercise-induced redistribution of tissue blood flow decreases the renal blood flow in an exercise intensity-dependent manner. However, the acute effects of incremental short maximal exercise on renal tubular conditions remain unknown. The purpose of this study was to investigate the acute effects of incremental short maximal exercise on the urinary liver-type fatty acid-binding protein, which is a highly sensitive tubular biomarker that correlates excellently with peritubular capillary blood flow. A total of 116 adults (aged 24-83 years) without chronic kidney disease performed the incremental short maximal exercise using a cycling ergometer, wherein the exercise sequence consisted of commencing with a 2-min workout period at 20 W (as a warm-up period) and then followed by a 10-20 W increase every 1 minute until termination criteria were reached. Urinary samples were gathered before and immediately after the exercise to evaluate the concentrations of urinary creatinine, albumin, and liver-type fatty acid-binding protein. Urinary excretion levels of albumin and liver-type fatty acid-binding protein were significantly increased post-exercise (P < .001 and P = .008, respectively). Furthermore, the % change in urinary liver-type fatty acid-binding protein levels after exercise was found to correlate independently with age, estimated glomerular filtration rate at baseline, and the % change in urinary albumin (Model R2  = 0.451, P < .001). Our findings suggest that incremental short maximal exercise may lead to acute slightly adverse effects on tubular conditions, especially in young adults or adults with lower renal function, even without chronic kidney disease.

The impact of aerobic fitness on arterial stiffness and adrenal cortex hormones in middle-aged and older adults.

An increase in arterial stiffness with advance aging is a risk for cardiovascular disease. Cardiovascular dysfunction is associated with the imbalance of adrenal cortex hormones, especially with the cortisol/dehydroepiandrosterone sulfate (DHEAs) ratio. However, the impact of aerobic fitness on arterial stiffness and cortisol/DHEAs ratio is unclear. The aim of this study was to investigate the relationship between aerobic fitness, arterial stiffness, and cortisol/DHEAs ratio. A total of 198 middle-aged and older adults (aged 50-79 years old) participated in this study. The aerobic fitness evaluated by peak oxygen consumption (VO2peak), carotid-femoral pulse wave velocity (cfPWV) as an indicator of arterial stiffness, and serum cortisol and DHEAs and their ratio were measured. The subjects were divided into the lower (n = 100) and the higher (n = 98) aerobic fitness groups based on the median value of VO2peak. There were no significant differences in serum cortisol and DHEAs concentration alone between the lower and higher fitness groups. However, the cortisol/DEHAs ratio and cfPWV in the higher fitness group was smaller than in the lower fitness group (p < 0.05). The cortisol/DHEAs ratio was significantly correlated with cfPWV (r = 0.159, p < 0.05). These findings suggest that the cortisol/DHEAs ratio is associated with aerobic fitness and arterial stiffness in middle-aged and older adults.

Sedentary behaviour, physical activity, and renal function in older adults: isotemporal substitution modelling.

BACKGROUND: Physical inactivity and sedentary behaviour (too much sitting) can contribute to renal dysfunction. However, the potential benefits of behavioural change (e.g. replacing sedentary behaviour with physical activity) on renal function are not well understood. We used isotemporal substitution to model potential impacts of behaviours on renal function by replacing time spent in one behaviour to another. METHODS: In 174 older Japanese adults (age, 50-83 years; females, 76%), the time spent in sedentary behaviour, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) were assessed using an uniaxial accelerometer. Renal function was evaluated by the estimated glomerular filtration rate (eGFR) from serum creatinine and cystatin C levels. RESULTS: In univariate analyses, eGFR was significantly, albeit weakly, correlated with time spent in sedentary behaviour (rs = - 0.229), LPA (rs = 0.265), and MVPA (rs = 0.353). In the isotemporal substitution models, replacement of 30 min/day of sedentary behaviour with an equivalent LPA time was not significantly associated with eGFR (ß = 2.26, p = 0.112); however, replacement with an equivalent time of MVPA was beneficially associated with eGFR (ß = 5.49, p < 0.05). CONCLUSIONS: These cross-sectional findings suggest that sedentary behaviour (detrimentally) and physical activity (beneficially) may affect renal function and that replacing sedentary behaviour with MVPA may benefit renal health in older adults.

Association between duration of excessive weight and arterial stiffness in middle-aged and older adults.

This study aims to evaluate the association between duration of overweight/obesity and arterial stiffness. In total, 103 men and women aged 45-68 years with a body mass index (BMI) of ≥25 kg/m2 were enrolled in this study. Duration of overweight/obesity was calculated for individuals with at least two consecutive BMI occurrences of ≥25 kg/m2 in the previous (5-year intervals from 20 years old) and present BMI information. Multiple regression analysis showed that carotid-femoral pulse wave velocity, an index of arterial stiffness, was independently associated with the duration of overweight/obesity, but not with current degree of overweight/obesity.

Effects of aerobic exercise training on the arterial stiffness and intramyocellular or extramyocellular lipid in overweight and obese men.

Intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) of ectopic fat in muscles are associated with arterial stiffness in normal-weight individuals. Furthermore, aerobic exercise training-induced changes in IMCL or EMCL content are related to a decrease in arterial stiffness in elderly people. Though arterial stiffness is strongly related with obesity, but the effects of aerobic exercise training on IMCL or EMCL content, with a particular focus on arterial stiffness, in obese individuals remains unclear. Here, we investigated the effects of aerobic exercise training on IMCL or EMCL content and arterial stiffness in obese individuals. First, in a cross-sectional study, we examined the relationship between arterial stiffness and IMCL or EMCL content in 24 overweight and obese men. Secondly, we investigated the effects of aerobic exercise intervention on arterial stiffness and IMCL or EMCL content in 21 overweight and obese men. In the cross-sectional study, EMCL content was positively correlated with baPWV and ß-stiffness index, whereas IMCL content was negatively correlated with baPWV. In the intervention study, there were no significant changes in baPWV, ß-stiffness index, and IMCL and EMCL contents after aerobic exercise training. However, exercise-induced change in baPWV and ß-stiffness index were positively correlated with changes in EMCL content. Moreover, the group of improvements in baPWV was only correlated significantly with reduced EMCL content. These results suggest that IMCL and EMCL contents may affect arterial stiffness in overweight and obese men.

An inducible knockout of Dicer in adult mice does not affect endurance exercise-induced muscle adaptation.

The contractile and metabolic properties of adult skeletal muscle change in response to endurance exercise. The mechanisms of transcriptional regulation in exercise-induced skeletal muscle adaptation, including fiber-type switching and mitochondrial biogenesis, have been investigated intensively, whereas the role of microRNA (miRNA)-mediated posttranscriptional gene regulation is less well understood. We used tamoxifen-inducible Dicer1 knockout (iDicer KO) mice to reduce the global expression of miRNAs in adult skeletal muscle and subjected these mice to 2 wk of voluntary wheel running. Dicer mRNA expression was completely depleted in fast-twitch plantaris muscle after tamoxifen injection. However, several muscle-enriched miRNAs, including miR-1 and miR-133a, were reduced by only 30-50% in both the slow and fast muscles. The endurance exercise-induced changes that occurred for many parameters (i.e., fast-to-slow fiber-type switch and increases in succinate dehydrogenase, respiratory chain complex II, and citrate synthase activity) in wild type (WT) also occurred in the iDicer KO mice. Protein expression of myosin heavy chain IIa, peroxisome proliferator-activated receptor-γ coactivator-1α, and cytochrome c complex IV was also increased in the iDicer KO mice by the voluntary running. Furthermore, there was no significant difference in oxygen consumption rate in the isolated mitochondria between the WT and iDicer KO mice. These data indicate that muscle-enriched miRNAs were detectable even after 4 wk of tamoxifen treatment and there was no apparent specific endurance-exercise-induced muscle phenotype in the iDicer KO mice.

Effects of oral curcumin ingested before or after eccentric exercise on markers of muscle damage and inflammation.

We examined the effect of curcumin (CUR) ingestion before or after exercise on changes in muscle damage and inflammatory responses after exercise. We conducted two parallel experiments with different CUR ingestion timings using a double-blind crossover. In Exp. 1, ten healthy men ingested 180 mg d-1 of CUR or placebo (PLA) 7 days before exercise. In Exp. 2, ten other healthy men ingested 180 mg d-1 of CUR or PLA 7 days after exercise. They performed 30 maximal isokinetic (120°s-1 ) eccentric contractions of the elbow flexors using an isokinetic dynamometer, and this was repeated with the other arm ≥4 weeks later. Maximal voluntary contraction (MVC) torque of the elbow flexors, elbow joint range of motion (ROM), muscle soreness, and serum creatine kinase (CK) activity were measured before, immediately after, and 1-7 days after exercise. Plasma interleukin-8 (IL-8) was measured before, immediately after, 12 hours after, and 1-7 days after exercise. The changes were compared over time. In Exp. 1, no significant differences were found between CUR and PLA subjects for each parameter. However, increases in IL-8 were significantly reduced 12 hours after exercise when CUR was ingested before exercise. In Exp. 2, compared to the PLA subjects, MVC torque and ROM were higher 3-7 days and 2-7 days after exercise (P < 0.05), respectively, whereas muscle soreness and CK activity were lower 3-6 days and 5-7 days after exercise (P < 0.05), respectively, in CUR subjects. CUR ingestion before exercise could attenuate acute inflammation, and after exercise could attenuate muscle damage and facilitate faster recovery.

Effect of sleep efficiency on salivary metabolite profile and cognitive function during exercise in volleyball athletes.

PURPOSE: Sleep duration is known to affect physiological and circadian metabolites and human homeostasis. However, little is known about the relationship between sleep quality and metabolite and cognitive function during exercise. Therefore, the aim of the present study was to investigate the impact of sleep quality on metabolite level and cognitive function in female volleyball athletes. METHODS: Twelve female volleyball athletes participated in this study. Sleep efficiency was measured for 1 week using NemuriSCAN (Paramount Bed Co. Ltd., Japan) as an index of sleep quality. The subjects were divided into better (n = 6) and lesser (n = 6) sleep quality groups by the median value of sleep efficiency. Saliva samples were collected using a Salimetric oral swab cotton and salivary metabolites were analysed using capillary electrophoresis and time-of-flight mass spectrometry. The subjects performed Stroop tasks (simple and difficult tasks) at rest and during aerobic exercise in recumbent cycle ergometer at light and heavy intensity. RESULTS: Increased sleep efficiency was found in the better sleep quality group, whereas total sleep time was similar. There were differences in urea cycle and Krebs cycle metabolites between the two groups; their levels were correlated with sleep efficiency. The difficult-task response time during heavy exercise was faster in the better sleep quality group. CONCLUSION: We demonstrated that sleep efficiency was associated with urea cycle and Krebs cycle metabolite levels and response time during heavy exercise in volleyball athletes. These results suggested that sleep quality may affect amino acid and energy metabolism and cognitive function during heavy exercise.

Effects of Taurine Supplementation on Vascular Endothelial Function at Rest and After Resistance Exercise.

High-intensity resistance exercise has been shown to increase arterial stiffness and reduce vascular endothelial function. Taurine supplementation has a favorable effect on maintaining vascular function. We had previously reported that taurine supplementation attenuated increases in resistance exercise-induced arterial stiffness. In the present study, we further investigate the effects of taurine supplementation on vascular endothelial function at rest and after resistance exercise.Twenty-nine healthy men were recruited and randomly assigned to either the placebo supplement group (n = 14) or the taurine supplement group (n = 15) in a double-blinded manner. Subjects were required to ingest 6 g of either a placebo or the taurine supplement for 2 weeks prior to and 3 days following the exercise. Two weeks after the commencement of supplementation, the subjects were asked to perform 2 sets of 20 repetitive unilateral maximal-effort resistance exercise of the elbow flexors on a Biodex isokinetic dynamometer, with each contraction lasting 3 s, with 1 repetition performed every 9 s and 4 min rest in between sets. We evaluated the changes in brachial artery flow-mediated dilation (FMD) in the non-exercised arm as an index of vascular endothelial function. Relative and absolute FMDs were measured prior to supplementation, before exercise, and 24, 48, and 96 h after exercise.Two weeks of taurine supplementation significantly increased both relative and absolute FMDs. Baseline diameter significantly increased at 96 h following the exercise in both groups. However, there was no change in the peak diameter. Consequently, both relative and absolute FMDs were significantly reduced at 96 h after the exercise in both groups. Taurine supplementation does not affect resistance exercise-induced reduction in FMD.Two weeks of taurine supplementation (6 g/day) significantly increased vascular endothelial function at rest; however, taurine supplementation did not improve resistance exercise-induced reduction in FMD.