The effects of type of recovery in resistance exercise on responses of platelet indices and hemodynamic variables.

To examine the effects of two different volume-matched resistance exercise (RE) recovery protocols (passive and active) on platelet indices and hemodynamic variables. Twelve Healthy participants (mean ± SD; 25 ± 3 yrs) completed a traditional resistance exercise (TRE) protocol that included three sets of six repetitions at 80% one repetition maximum (1RM) with two minutes passive recovery between sets, exercises and an interval resistance exercise (IRE) protocol that included three sets of six repetitions at 60%1RM followed by active recovery including six repetitions of the same exercise at 20%1RM. Blood samples for multiple platelet indices were taken before the protocols, immediately-post (IP), and after 1-hour recovery. Hemodynamic variables were measured before, IP, and every five minutes during recovery. Mean platelet volume and platelet large cell ratio P_LCR decreased from baseline to recovery. Heart rate (HR) and rate pressure product (RPP) were augmented at IP following IRE compared to TRE. HR was significantly elevated for 20 minutes after both RE protocols, and RPP recovered by five minutes. Systolic blood pressure was increased at IP compared to baseline and all recovery time points for both RE protocols. Our research demonstrated that both RE protocols, produced transient increases in platelet indices (MPV, and P_LCR) and hemodynamic variables (SBP, HR, and RPP), all of which returned to baseline within an hour. Notably, the IRE protocol elicited a greater increase in HR and RPP compared to the TRE protocol.

Cardiac structure and function of elite volleyball players across different playing positions.

BACKGROUND: Volleyball is a popular Olympic sport but has been little studied. Volleyball players have very distinct roles based on their playing positions. The present study aimed to investigate and compare cardiac functions and structure in elite volleyball players across different playing positions. METHODS: Left ventricular structure and function were measured using echocardiography in 60 male professional volleyball players (30.6±3.6 years) across five playing positions including libero, opposite players, outside hitters, middle blockers, and setters. RESULTS: Significant differences in most echocardiographic variables were observed among different playing positions, including left ventricular (LV) internal dimension, posterior wall thickness, intact ventricular septum, stroke volume, cardiac output, end-diastolic volume, ejection fraction, and fractional shortening (all P<0.01). End-systolic volume was not different among positions (P=0.167). The opposite players demonstrated greater LV dimension and thickness as well as systolic function than players in other positions (P<0.05). Stroke volume in the setters was significantly lower than those of the opposite players and outside hitters (P<0.05). Regression analysis showed that the playing position independently predicted most of the echocardiographic variables (P<0.05). CONCLUSIONS: LV adaptations in volleyball players vary widely according to their playing positions. The opposite players had the most pronounced LV adaptations compared with player in other positions.

Comparable effects of circuit and traditional resistance exercise on platelet α2bß3 receptor and platelet activation and function.

BACKGROUND: Resistance exercise induces thrombocytosis and increases platelet activation and function. These changes might be related to exercise variables including exercise intensity and type. OBJECTIVE: We compared the effects of traditional resistance exercise (TRE) and circuit resistance exercise (CRE) on cellular markers of platelet activation and function. METHODS: In this crossover study ten healthy male (mean±SD: age, 25.6±2.4 years) subjects performed TRE encompassed 3 sets of 10 repetitions at 100% of 10-RM (10 repetition maximum) for 6 exercises, and CRE protocols included 3 sets of 10 repetitions at 100% of 10-RM for all 6 exercises consecutively, in two separate weeks. To measure platelet indices, PAC1, CD41a, CD42b and CD62P three blood samples were taken before, immediately after exercise, and after 30 min recovery. RESULTS: Lactate concentration, blood pressure, platelet count (PLT), and mean platelet volume (MPV) were significantly (p < 0.05) increased following both resistance exercise trials. Significant increases in PAC1, and CD62P; and significant reductions for CD42b and CD41a were detected following both REs (p < 0.05). However, changes in PAC1 and CD62P were significantly different between the two protocols (p < 0.05), with higher increases detected following CRE. CONCLUSIONS: Acute RE increases platelet indices and platelet activation; and that CRE results in higher platelet activation than TRE, probably due to exercise-induced increases in shear stress.

The Effects of Alpha-Glycerylphosphorylcholine on Heart Rate Variability and Hemodynamic Variables Following Sprint Interval Exercise in Overweight and Obese Women.

The current study examined the effects of Alpha-Glycerylphosphorylcholine (A-GPC) on heart rate variability (HRV) and hemodynamic responses following a sprint interval exercise (SIE) in women who were overweight or obese. Participants (n = 12, 31.0 ± 4.6 years; 29.4 ± 2.1 kg/m2) consumed 1000 mg of A-GPC or a placebo after eating breakfast in a randomized, double-blind cross-over design. After 60 min, participants performed two bouts of the SIE (30 s Wingate) interspersed with 4 min of active recovery (40 rpm). Hemodynamic variables and HRV domains were measured before and 60 min after the A-GPC consumption, immediately after SIE, and every 15 min up to 120 min during recovery. A-GPC consumption increased resting levels of both the time domain (Standard Deviation of RR wave intervals [SDNN] and percentage of interval differences of adjacent RR intervals greater than 50 ms [pNN50%]) and frequency domain (high frequency [HF] and low frequency [LF]) variables of HRV (p < 0.05). Moreover, HRV variables (except for LF/HF) decreased (p < 0.05) immediately after SIE in the A-GPC and placebo sessions. Systolic and diastolic blood pressure increased (p < 0.05) immediately after SIE in both trials. Both HRV and hemodynamic variables recovered (p < 0.05) faster in the A-GPC compared to the placebo session. We concluded that A-GPC consumption recovers HRV and blood pressure faster following strenuous exercise in overweight and obese women, and that it might favorably modify cardiac autonomic function.

Effect of Lower- versus Higher-Intensity Isometric Handgrip Training in Adults with Hypertension: A Randomized Controlled Trial.

This study compared the effects of lower- versus higher-intensity isometric handgrip exercise on resting blood pressure (BP) and associated clinical markers in adults with hypertension. Thirty-nine males were randomly assigned to one of three groups, including isometric handgrip at 60% maximal voluntary contraction (IHG-60), isometric handgrip at 30% IHG-30, or a control group (CON) that had been instructed to continue with their current activities of daily living. The volume was equated between the exercise groups, with IHG-60 performing 8 × 30-s contractions and IHG-30 performing 4 × 2-min contractions. Training was performed three times per week for 8 weeks. Resting BP (median [IQR]), flow-mediated dilation, heart rate variability, and serum markers of inflammation and oxidative stress were measured pre- and post-intervention. Systolic BP was significantly reduced for IHG-60 (−15.5 mmHg [−18.75, −7.25]) and IHG-30 (−5.0 mmHg [−7.5, −3.5]) compared to CON (p < 0.01), but no differences were observed between both the exercise groups. A greater reduction in diastolic BP was observed for IHG-60 (−5.0 mmHg [−6.0, −4.25] compared to IHG-30 (−2.0 mmHg [−2.5, −2.0], p = 0.042), and for both exercise groups compared to CON (p < 0.05). Flow-mediated dilation increased for both exercise groups versus CON (p < 0.001). IHG-30 had greater reductions in interleukin-6 and tumor necrosis factor-α compared to the other groups (p < 0.05) and CON (p = 0.018), respectively. There was a reduction in Endothelin-1 for IHG-60 compared to CON (p = 0.018). Both the lower- and higher-intensity IHG training appear to be associated with reductions in resting BP and improvements in clinical markers of inflammation and oxidative stress.

Responses of platelet CD markers and indices to resistance exercise with and without blood flow restriction in patients with type 2 diabetes.

BACKGROUND: Diabetes mellitus is a common disorder with the risk of vascular injury. OBJECTIVE: The aim of this study was to compare the effects of low-intensity resistance exercise with blood flow restriction versus high-intensity resistance exercise on platelet CD markers and indices in patients with type 2 diabetes. METHODS: Fifteen female patients with type 2 diabetes (Mean±SD; age, 47.6±7.2 yrs) randomly completed two resistance exercise at an intensity corresponding to 20% and 80% of one-repetition maximum (1-RM), with and without blood flow restriction (REBFR and RE), respectively. We measured markers of platelet activation (P-selectin, GpIIb/IIIa, and CD42) and platelet indices before and immediately after exercise, and after 30 min recovery. RESULTS: Platelet count (PLT) and plateletcrit (PCT) increased in response to REBFR more than the RE (p < 0.05), though, no significant differences in PDW and MPV were observed (p < 0.05). Although P-selectin (CD62P), CD61, CD41, and CD42 were reduced following resistance exercise in both trials, these reductions were non-significant (p < 0.05). Besides, no significant between-group differences were found for platelet CD markers (p < 0.05). CONCLUSIONS: It is concluded that REBFR induces thrombocytosis, but responses of platelet CD markers in patients with type 2 diabetes are similar following low-intensity REBFR and high-intensity RE.

Time-varying association between physical activity and risk of diabetes in the early and late adulthood: A longitudinal study in a West-Asian country.

BACKGROUND: The time-varying association between physical activity (PA) and incidence of type 2 diabetes (T2DM) is still unclear. The present study aimed to investigate this association in the early- and late-adulthood during a 9-year follow-up. METHODS: This study was conducted on 3905 participants in early and late adulthood, using the Tehran Lipid and Glucose Study (TLGS) dataset. PA was assessed via the Iranian version of Modified Activity Questionnaire (MAQ). The association between trend of PA and incident T2DM was investigated using time-varying Cox's proportional hazard model. Variables including job, education, smoking and body mass index (BMI) were adjusted in the final model. RESULTS: The distribution of sex- and age-specific levels of PA changed significantly over time. Compared with physically inactive women, for older women with high level of PA, the risk of T2DM was 0.64 (95% CI: 0.43-0.95, P = 0.02) in adjusted model. Moreover, hazard for low PA group was significantly higher than the moderate group, and for these two groups were significantly higher than high PA level (P < 0.05). CONCLUSION: High PA level can postpone the incident T2DM in early-aged and elderly women, over time. Therefore, gender and age are of great importance in designing the PA modifying programs to prevent T2DM.

Effect of Acute Ramadan Fasting on Muscle Function and Buffering System of Male Athletes.

The aim of this study was to investigate the effect of acute Ramadan fasting (RF) on the muscle function and buffering system. Twelve male athletes with 8 years of professional sports experience (age, 23.2 ± 1.3 years, body mass index: 24.2 ± 2.2 kg/m2) participated in this study. The subjects were tested twice, 3 weeks after the beginning of RF and 2 weeks after the end RF. Muscle function, buffering capacity, and rating of perceived exertion (RPE) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6-20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3-) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6-20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3-) were taken immediately after 25 repetitions of isokinetic knee flexion and extension. Measures taken during isokinetic knee extension during RF were significantly lower than those after RF in extension peak torque (t = -4.72, p = 0.002), flexion peak torque (t = -3.80, p = 0.007), extension total work (t = -3.05, p = 0.019), extension average power (t = -4.20, p = 0.004), flexion average power (t = -3.37, p = 0.012), blood HCO3- (t = -2.02, p = 0.041), and RPE (Z = -1.69, p = 0.048). No influence of RF was found on the blood pH (t = 0.752, p = 0.476). RF has adverse effects on muscle function and buffering capacity in athletes. It seems that a low-carbohydrate substrate during RF impairs muscle performance and reduces the buffering capacity of the blood, leading to fatigue in athletes.

L-Arginine Improves Endurance to High-Intensity Interval Exercises in Overweight Men.

The effects of acute consumption of L-Arginine (L-Arg) in healthy young individuals are not clearly defined, and no studies on the effects of L-Arg in individuals with abnormal body mass index undertaking strenuous exercise exist. Thus, we examined whether supplementation with L-Arg diminishes cardiopulmonary exercise testing responses, such as ventilation (VE), VE/VCO2, oxygen uptake (VO2), and heart rate, in response to an acute session of high-intensity interval exercise (HIIE) in overweight men. A double-blind, randomized crossover design was used to study 30 overweight men (age, 26.5 ± 2.2 years; body weight, 88.2 ± 5.3 kilogram; body mass index, 28.0 ± 1.4 kg/m2). Participants first completed a ramped-treadmill exercise protocol to determine VO2max velocity (vVO2max), after which they participated in two sessions of HIIE. Participants were randomly assigned to receive either 6 g of L-Arg or placebo supplements. The HIIE treadmill running protocol consisted of 12 trials, including exercise at 100% of vVO2max for 1 min interspersed with recovery intervals of 40% of vVO2max for 2 min. Measurements of VO2 (ml·kg-1·min-1), VE (L/min), heart rate (beat per min), and VE/VCO2 were obtained. Supplementation with L-Arg significantly decreased all cardiorespiratory responses during HIIE (placebo+HIIE vs. L-Arg+HIIE for each measurement: VE [80.9 ± 4.3 L/min vs. 74.6 ± 3.5 L/min, p < .05, ES = 1.61], VE/VCO2 [26.4 ± 1.3 vs. 24.4 ± 1.0, p < .05, ES = 1.8], VO2 [26.4 ± 0.8 ml·kg-1·min-1 vs. 24.4 ± 0.9 ml·kg-1·min-1, p < .05, ES = 2.2], and heart rate [159.7 ± 6.3 beats/min vs. 155.0 ± 3.7 beats/min, p < .05, d = 0.89]). The authors conclude consuming L-Arg before HIIE can alleviate the excessive physiological strain resulting from HIIE and help to increase exercise tolerance in participants with a higher body mass index who may need to exercise on a regular basis for extended periods to improve their health.

Effect of Sixteen Weeks Combined Training on FGF-23, Klotho, and Fetuin-A Levels in Patients on Maintenance Hemodialysis.

INTRODUCTION: Fibroblast growth factor 23 (FGF-23) and its cofactor alfa klotho, are one of the most important factors, directly and indirectly, involved in the process of calcification and atherosclerosis. This study aimed to evaluate the efficacy of a combination of regular exercise during dialysis on quality of life and markers including FGF-23, alfa klotho, and fetuin-A levels. METHODS: Forty-five hemodialysis patients aged 61 ± 9.02 years and weight 69 ± 11.25 kg were randomly divided into two training, EX (n = 24) and control groups, CON (n = 21). The EX group patients participated in a 16-week combined aerobic and resistance exercise program during dialysis. Bone markers including, FGF-23, klotho, fetuin-A, were measured before and at the end of the study in both groups. Statistical analysis for comparing data change during study by SPSS software and the P value was set at .05. RESULTS: In the control group in the secondary assessment, reduction in quality of life was observed (P < .05). Significant change in growth factor 23, CRP, and fetuin-A was not observed in exercise and control groups (P > .05), however significant rising of klotho was observed in treated patients (P < .05). Also, combined training reduced the amount of phosphorus, parathyroid hormone; significantly (P < .05). CONCLUSION: This study showed that regular exercise during dialysis improves quality of life and physical functions. No significant change in FGF-23 and CRP were observed during the study. However significant rising of klotho and reduction of iPTH and phosphorous levels were observed in treated patients.

Acute responses of platelet count and ADP-induced platelet aggregation to different high intensity interval exercise modes.

BACKGROUND: Platelet activation is associated with abdominal obesity and exercise training is an important modulator of body weight. OBJECTIVE: We investigated the effects of two high intensity interval exercise (HIIE) protocols of different intensity and duration on platelet indices and platelet aggregation in overweight men. METHODS: Ten overweight men performed 6 intervals of 30s exercise at 110% of peak power output (PPO) interspersed by 3 : 30 min active recovery (1/7 protocol) at 40% of PPO and 6 intervals of 2 min exercise at 85% of PPO interspersed by 2 min active recovery (1/1 protocol) at 30% of PPO in two separate sessions. Platelet indices and platelet aggregation were measured before and immediately after both HIIEs. RESULTS: Platelet indices increased significantly following HIIE (P < 0.05), though, significant differences between the two protocols were only detected for platelet count, which was markedly increased following 1/1 protocol. Platelet aggregation increased significantly (P < 0.05) in response to the two HIIE protocols, with no significant difference being observed between the two protocols (P > 0.05). CONCLUSIONS: It is concluded that HIIE leads to transient increases in markers of thrombus formation and that work to rest ratio is an important factor when investigating the changes in thrombocytosis following HIIE.

High-intensity interval training irrespective of its intensity improves markers of blood fluidity in hypertensive patients.

Aim: The present study examined and compared the effects of two different HIIT (High-intensity interval training) protocols on markers of blood fluidity in hypertensive patients.Methods: Thirty hypertensive (stage 1, systolic BP >140 and diastolic BP>90 mmHg) patients (age, 47.96 ± 3.20 yrs), were randomly allocated to short-duration HIIT (SDHIIT, n = 10), long-duration HIIT (LDHIIT, n = 10), and control (n = 10) groups. After 2 weeks of continuous mild training, patients in SDHIIT group performed 8 weeks of HIIT included 27 min HIIT that encompassed 27 repetitions of 30 s activity at 80%-100% of VO2peak interspersed by 30 s passive/active (10%-20% of VO2peak) recovery, while, patients in LDHIIT group performed 8 weeks of HIIT (32 min per session) included 4 repetitions of 4 min activity at 75%-90% of VO2peak interspersed by 4 min passive/active (15%-30% of VO2peak) recovery. Two blood samples were taken before and after training and were analyzed for hemorheological variables.Results: Significant (P < .05) reductions in systolic blood pressure (SBP), blood and plasma viscosity, fibrinogen concentration and red blood cell (RBC) aggregation (8-12%) were found following two training protocols (P < .05), though, the differences between adaptations were not statistically significant (P > .05). In addition, HIIT protocols increased RBC deformability significantly (P < .05), with no significant differences being observed between two protocols.Conclusion: It is concluded that HIIT training reduces SBP and markers of blood fluidity in patients with stage 1 hypertension irrespective of the HIIT intensity and duration. Therefore, this type of exercise training could be prescribed for improving the blood fluidity markers in hypertensive patients.

Improvements in soccer-specific fitness and exercise tolerance following 8 weeks of inspiratory muscle training in adolescent males.

BACKGROUND: Inspiratory muscle training has been shown to improve exercise performance, however there is limited evidence for its effectiveness in soccer players. This study investigates the effect of inspiratory muscle training on soccer-specific fitness and exercise tolerance in adolescent male players. METHODS: Thirty highly trained soccer players (16-19 y) were randomly assigned into one of three groups: experimental 1 (N.=10), experimental 2 (N.=10) and sham-control (sham, N.=10). All groups performed inspiratory muscle training twice per day and five times per week for 8 weeks. Experimental 1 performed 25-35 breaths at 55% maximal inspiratory pressure, experimental 2 performed 45-55 breaths at 40% maximal inspiratory pressure, whereas sham performed 30 breaths at 15% maximal inspiratory pressure. Measures before and after the intervention involved the Yo-Yo Intermittent Recovery test level 1, running-based anaerobic test, repeated high-intensity endurance test, maximal inspiratory pressure, and spirometry. RESULTS: Yo-Yo Intermittent Recovery test level 1: distance increased for experimental groups 1 and 2 compared to sham (P=0.012 and P=0.031, respectively), with no difference between experimental groups. Fatigue index calculated from running-based anaerobic test improved for experimental groups 1 and 2 compared to sham (P=0.014 and P=0.011, respectively), with no difference between experimental groups. Exercise tolerance (i.e. blood lactate concentration, perceived exertion and perceived breathlessness) following the repeated high-intensity endurance test decreased in experimental groups 1 and 2 compared to sham (P <0.05), with no difference between experimental groups. Maximal inspiratory pressure increased for experimental groups 1 and 2 compared to sham (P=0.000), with no difference between experimental groups. There were no changes for the spirometry measures. CONCLUSIONS: Improvements in soccer-specific fitness and exercise tolerance can be achieved using inspiratory muscle training protocols of varying intensities and volumes.

Acute L-Arginine supplementation does not affect red blood cell aggregation and deformability during high intensity interval exercise in healthy men.

BACKGROUND: L-Arginine, the precursor of NO might be involved in improving the cardiovascular disorders via regulation of functional properties of erythrocytes. OBJECTIVE: This study investigated the effects of L-Arginine supplementation on responses of red blood cell (RBC) properties to high intensity interval exercise (HIIE). METHODS: Ten overweight healthy men participated voluntarily in the study and performed two HIIE trials with and without L-Arginine in two separate weeks. The HIIE protocol included 12 intervals of 3-min encompassed 1-min running at 100% of vVO2max and 2-min active recovery at 40% of vVO2max. Three blood samples were taken before and after supplementation, and immediately after exercise; and were used to measure red blood cell properties. RESULTS: The HIIE protocol increased hematocrit, hemoglobin and lactate significantly (P < 0.05), but had no significant effect on RBC aggregation, RBC deformability, and fibrinogen concentration. When data were compared for two trials no significant differences between the responses of RBC properties to two HIIE protocols were detected (P > 0.05), whereas the increases in lactate concentration following HIIE was significantly lower in L-Arginine than placebo trial (P < 0.05). CONCLUSIONS: It is concluded that L-Arginine consumption prior to HIIE does not lead to any improvement in RBC properties during HIIE in overweight healthy men.

Short-Duration High-Intensity Interval Exercise Training Is More Effective Than Long Duration for Blood Pressure and Arterial Stiffness But Not for Inflammatory Markers and Lipid Profiles in Patients With Stage 1 Hypertension.

PURPOSE: The present study compared the effects of 2 different high-intensity interval training (HIIT) protocols on arterial stiffness, lipid profiles, and inflammatory markers in hypertensive patients. METHODS: Thirty hypertensive (stage 1) patients, aged 48.0 ± 3.2 yr, were randomly allocated to the short-duration HIIT (SDHIIT, n = 10), long-duration HIIT (LDHIIT, n = 10), and control (n = 10) groups. After a 2-wk preparatory phase of continuous mild training, patients in the SDHIIT group performed 8 wk of HIIT including 27 repetitions of 30-sec activity at 80% to 100% of (Equation is included in full-text article.)O2peak interspersed with 30-sec passive/active (10%-20% of (Equation is included in full-text article.)O2peak) recovery. Patients in the LDHIIT group performed 8 wk of HIIT, 32 min/session including 4 repetitions of 4-min activity at 75% to 90% of (Equation is included in full-text article.)O2peak interspersed with 4-min passive/active (15%-30% of (Equation is included in full-text article.)O2peak) recovery. Blood pressure (BP), pulse wave velocity (PWV), inflammatory markers, and lipid profiles were measured before and after training. RESULTS: Significant (P < .05) reductions in systolic blood pressure and PWV were found following 2 training protocols, though, only the changes in PWV following the SDHIIT were significantly different than those in the LDHIIT and control groups. Interleukin-6 and triglycerides decreased and interleukin-10 increased significantly (P < .01) following both HIIT programs, whereas the differences between the 2 training protocols were not statistically significant. C-reactive protein and lipids did not change significantly following HIIT. CONCLUSIONS: Performing HIIT improves systolic blood pressure and inflammatory markers in patients with stage 1 hypertension irrespective of the HIIT intensity and duration, and PWV improvement is intensity related.

Effects of endurance training on hsa-miR-223, P2RY12 receptor expression and platelet function in type 2 diabetic patients.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with thrombotic events due to platelets' defects. OBJECTIVE: The aim of this study was to investigate the effects of endurance training on expressions of platelet hsa-miR-223 and P2RY12 receptor, as well as platelet function in T2DM patients. METHODS: Twenty female T2DM patients (age, 62.25±3.81 yr; weight, 73.53±9.04 kg; height, 154.7±4.3 cm) were randomly divided into two groups (Control (CONT) and endurance training (ET)). Subjects in ET group performed eight weeks of running on treadmill at 60-75% of VO2peak (moderate intensity), 3 sessions per week, while, the subjects in control group were not involved in any kind of exercise training. Two blood samples were taken before and 48 h after the training and were analyzed for platelet aggregation, and hsa-miR-223 and P2RY12 expressions. RESULTS: Although platelet aggregation decreased significantly in ET group (P <  0.05), these changes were not significantly different between two groups. Expression of platelet hsa-miR-223 increased and P2RY12 mRNA reduced following ET non-significantly. However, decreases in fasting blood glucose, glycated hemoglobin and body weight, and increases in VO2peak following ET were significantly different when compared to control group (P <  0.05). CONCLUSIONS: Short-term endurance training dose not induce up-regulation of hsa-miR-223 and down-regulation of P2RY12, while it has a positive impact on platelet function, glycemic indices, physical fitness and body composition in female T2DM patients.

Influences of two high intensity interval exercise protocols on the main determinants of blood fluidity in overweight men.

BACKGROUND: Acute effects of continuous exercise on the markers of blood fluidity have been addressed in different populations and the changes are intensity related. However, the effect of different high intensity interval exercise (HIIE) on these variables is unclear. OBJECTIVE: This study is designed to determine the effects of two different HIIE with different work/rest ratios but the same energy expenditure on the main determinants of blood fluidity. METHODS: Ten overweight men (age, 26.3±1.7 yrs) completed two HIIE protocols on two separate occasions with one week intervening. The two HIIE encompassed performing: 1) 6 intervals of 2 min activity at 85% of VO2max interspersed by 2 min active recovery at 30% of VO2max (ratio 1 to 1, HIIE1/1), and 2) 6 intervals of 30 s activity at 110% of VO2max interspersed by 4 min active recovery at 40% of VO2max (ratio 1 to 8, HIIE1/8). Each exercise trial was followed by 30 min rest. Venous blood samples were obtained before exercise, immediately after exercise and after recovery and analyzed for blood and plasma viscosity, fibrinogen and red blood cell indices. RESULTS: The HIIE1/1 protocol led to higher reduction (P < 0.01) in plasma volume changes compared to HIIE1/8 (9.9% vs 5.7%). Moreover, increases in blood viscosity, plasma viscosity, hematocrit, RBC count and mean arterial blood pressure observed following HIIE1/1 were significantly (P < 0.05) higher than HIIE1/8 ; whereas, the changes in fibrinogen concentration neither were significant in response to both trials nor were significantly different between two protocols (P > 0.05). However, the changes in all variables during exercise were transient and returned to the baseline levels after 30 min recovery. CONCLUSIONS: It is concluded that the HIIE protocol with lower intensity and shorter rest intervals (higher work to rest ratio) clearly results in more physiological strain than HIIE with higher intensity but longer rest intervals (lower work to rest ratio) in overweight individuals, and that the work to rest ratio could be as important as exercise intensity when considering the hemorheological variables during HIIE.

Platelet activation and function in response to high intensity interval exercise and moderate continuous exercise in CABG and PCI patients.

BACKGROUND: The effects of high intensity interval training (HIIT) on inflammatory markers and endothelial function have been extensively shown. However, the acute effect of HIIT on platelet activation and function in patients with recent revascularization is unclear. OBJECTIVE: The purpose of present study was to compare the responses of platelet activation (CD62P) and function (platelet aggregation) to high intensity interval exercise (HIIE) and moderate continuous exercise (MCE) in coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI) patients. METHODS: Thirty patients who had CABG or PCI were randomly divided into HIIE, MCE and control groups. After determining the VO2peak, subjects in the MCE group carried out 30 min of continuous exercise at 60% of VO2peak, whereas, the subjects in HIIE group performed an interval protocol consisted of 8 repetitions of 2 min activity (running on treadmill) at 90% of VO2peak interspersed by 2 min of active recovery between repetitions at 30% of VO2peak .  Subjects in control group were seated and had no activity for the same period of time. Two blood samples were collected before and immediately after exercise and were analyzed for markers of platelet activation and function. RESULTS: Data analyzes revealed that increases in platelet aggregation induced by ADP and corrected for increases in platelet count in response to MCE trial was significantly lower than HIIE group (P < 0.05). In addition, responses of CD62P to MCE trial was significantly lower compared to HIIE group (P < 0.05). Changes in plateletcrit and platelet distribution width were significantly different among the three trials where the PCT and PDW following the HIIE were higher than MCE. Platelet count increased significantly (P < 0.05) by 13% following HIIE trial. CONCLUSIONS: Based on the findings of the present study it could be concluded that the risk of exercise-induced thrombosis is higher during HIIE than MCE in patients with recent revascularization.

The effects of short-term high-intensity interval training vs. moderate-intensity continuous training on plasma levels of nesfatin-1 and inflammatory markers.

OBJECTIVES: Exercise training is an effective method of weight management, and knowing about its influence on the hormones involved in the regulation of food intake and inflammation could be useful for body weight management. Therefore, the purpose of this study was to compare the effects of 6 weeks of high-intensity interval training (HIIT) and moderate-intensity continuous exercise training (MCT) on nesfatin-1, interleukin (IL)-6, and tumor necrosis factor alpha (TNF-α). DESIGN AND METHODS: Thirty sedentary overweight men (Mean±SD; age, 25±1 years) were divided into three (n=10) body mass index-matched groups. The participants in the training groups performed either HIIT or MCT protocols 3 days per week for 6 weeks followed by a week of detraining. RESULTS: Plasma IL-6 and TNF-α did not significantly change after training, but nesfatin increased significantly only with HIIT compared with the control group (p<0.05). In addition, fasting glucose, insulin, and homeostasis model estimated insulin resistance (HOMA-IR), decreased significantly following both HIIT and MCT training (p<0.05). After a detraining period, the plasma nesfatin-1 did not return to pre-training levels in the HIIT group. CONCLUSIONS: Both the HIIT and MCT groups had similar effects on inflammatory markers and insulin resistance in men who are overweight, but the HIIT seems to have better anorectic effects (as indicated by nesfatin) compared with MCT.

Reliability and validity of the Iranian version of the QAPACE in adolescents.

PURPOSE: The aim of this study was to determine the reliability and validity of the Iranian version of the Quantification de l'Activite Physique en Altitude Chez les Enfants (QAPACE) in adolescents. METHODS: After linguistic validation, the Iranian version of the QAPACE was completed by 359 (52.4 % girls) schoolchildren, aged 15-18 years. Test-retest reliability of the questionnaire was determined by intraclass correlation coefficients (ICCs). For validation purposes, two methods were used for (1) the correlation between VO2peak and the DEE and (2) known-group validity, which was examined by comparing the normal weight adolescents and those who were overweight/obese. RESULTS: ICCs for test-retest ranged from 0.79 to 0.98. The mean scores in test-retest surveys for total score and all of the subscores were significant (p < 0.05). Sex-specific analysis showed a significant correlation between VO2peak and DEE over 12-month, school, and vacation periods in girls (p < 0.05). The mean values for all activities except for transportation, other activities in school, personal artistic activities, sport competition, and home activities were significantly lower in overweight/obese group than normal group. CONCLUSION: Our results support the initial reliability and validity of the Iranian version of QAPACE as a daily physical activity measure in adolescents.