نشریه مطالعات کاربردی تندرستی در فیزیولوژی ورزش
سال هشتم شماره 2 (پاییز و زمستان 1400)

Both hypoxia and hypocapnia can cause broncho-constriction in humans, and this could have a bearing on performance at high altitude. This can be a problem for non-natives and non-professional climbers. The purpose of this study was to investigate the effect of one-week stay at a height above 3600 m of sea level on the pulmonary indexes of men non-professional climber.

Ten non-professional climbers from Ardabil Red Crescent Society (with an average age of 28.6±4.78) voluntarily participated in this semi-experimental study. Pulmonary function indices, blood pressure and heart rate were measured at the baseline level of 1400 m, after climbing to an altitude of 3600 m and then after a week of staying at an altitude. Data were analyzed using analysis of covariance with repeated measures at a significance level of P<0.05.

The results of the study showed that Peek Expiratory flow (p=0/04) and blood pressure decreased significantly after ascent to 3600 m and one week living at high altitude.   In addition, FEV1/FVC had a significant increase after ascent to high altitude (p = 0.04). No significant change was observed in other measured indices (p>0.05).

These findings might underlie “live high” strategy prescription for ergogenic aids as well as hypertension control.  However, more firm conclusion warrants to be verified in future studies.

There are not any detailed knowledge of the effectiveness of morning fasting exercise training on stress and growth hormone levels and the cardiovascular health of young soldiers. Thus, the aim of this study was to investigate the effects of morning exercise training in fasted vs carbohydrate intake on serum levels of cortisol, testosterone and cardiovascular risk factors.

 In a quasi-experimental field study, twenty-four soldiers with moderate to low level of fitness(vo2max<44) were selected from all 18 to 24-year-old soldiers in barracks. Participant were randomly divided into two groups: cryohydrate supplement (n = 12) and placebo (n = 12). The supplement group consumed 6% sucrose solution before starting morning exercises. The morning exercise program consisted of 60 minutes of moderate-intensity aerobic exercise for 6 weeks (4 sessions per week). Before and 48 hours after the last training session, blood samples were collected and other evaluations were measured. Data were analyzed using ANCOVA with a significance level of p <0.05.

 The use of 6% sucrose supplement had a significant effect on cortisol level (p =0.01) and testosterone to cortisol ratio (p =0.028) and waist circumference (p =0.001) in the experimental group compared to the control group. But it had no significant effect on testosterone level and cardiovascular indices (p <0.05).

 Morning exercise training combined with a carbohydrate supplementation compared to fasting can play an important role in the health of young men by lowering cortisol and abdominal obesity, as well as establishing an  anabolic and catabolic balance.

 Myostatin and insulin-like growth factor play an important role in responding to muscle contractions, regulating and stimulating muscle metabolism. The aim of this study was to change plasma myostatin and IGF-1 to eight weeks of intense intermittent exercise in obese adolescents.  

 This study was a quasi-experimental study and 28 obese adolescents were randomly divided into experimental and control groups. The experimental group performed a very intense intermittent training protocol for eight weeks and three sessions per week. In order to measure the plasma levels of myostatin and IGF-1, blood samples were taken in two stages in the fasting state, 48 hours before and after exercise. A correlated t-test was used for intra-group comparison and an independent t-test was used for comparison between groups.

  The results showed that after eight weeks of very intense interval training, plasma myostatin levels significantly decreased (P=0.001) and IGF-1 (P=0.013) compared to the control group.

According to the findings of the present study that a significant reduction of myostatin and the significant increase in IGF-1, high-intensity interval training can be used as a non-pharmacological strategy for prevention and improvement in obese adolescents.

Adipocytokines play an important role in controlling energy homeostasis, and in various metabolic processes related to obesity.  Therefore, the aim of the present study is to investigate the effects of 8-week of combined exercise training on plasma leptin and adiponectin levels in obese boys.

A total of 40 obese boys (age: 12.7±0.46 years, weight 78.46±10.19 kg, height 161.72±8.16 cm, and body fat 33.04±4.30 %) were divided into two combined exercise training (CT) and control groups. Subjects in the CT group participated in a combined aerobic (30 min) and resistance (one set of 7 resistance exercises) training program 3 times/week for 8 weeks, whereas those in the control group had no regular exercise and continued their routine daily activities. Body mass, body fat, plasma leptin and adiponectin levels were measured before and after the training program.  The data were compared using Paired and ‌independent t-test.

The between-group comparison showed that body fat percentage (P=0.42), body weight (P=0.88) and plasm leptin level (P=0.065) did not change significantly after combined exercise training; however, plasma adiponectin level (P=0.001) and adiponectin/ body fat (%) ratio (P= 0.014) increased significantly in response to combined exercise training.

The results indicated that eight-week combined exercises training increased plasma adiponectin level in childhood obesity. Furthermore, regular physical activity without simultaneous changes in body composition level had no significant effect on leptin level.

Start or continuation of physical activity can especially be a challenge for non-athletes due to exercise-induced muscle injuries. Therefore, the purpose of this study was to investigate the dose-dependent effects of beta-hydroxy beta-methyl butyrate (HMB -FA) on muscle and liver damage indices induced by high-intensity eccentric resistance exercise in non-athlete girls.

24 non-athlete girls (age= 25.87±1.65 years, BMI=20.97±1.36) selected from volunteers to participate in this study. Participants were randomly divided into three HMB-FA supplementation groups (n=8) with doses of (HMB-1.5) 1.5, (HMB-3) 3, and (HMB-4) 4 g/d. After six days of supplementation, an eccentric resistance session with a maximum intensity of 120% was carried out. Blood and urine samples were collected in 4 stages including before supplementation, before exercise, immediately, and 24 hours after exercise. For comparison of the results, 3×4 variance analysis was used.

The results showed that different doses of supplementation had no significant effect on blood levels of AST and ALT as well as urine levels of creatinine and urea. However, LDH and CK levels showed significant inter and intragroup differences(p<0.05). Results showed that values of CK and LDH between HMB-1.5 and other groups had significant differences at 24h post-exercise session.

Considering significant differences in enzymatic indices of CK and LDH between 1.5g/d supplementation with 3 and 4 g/d doses, we conclude that 1.5g/d dose should not be considered as an inhibitor of high-intensity exercise-induced muscle damage. Also since 3 and 4 g/d showed no differences in inhibiting muscle and liver damage indices in blood and urine, the lower dose (3g/d) can be our prescription as the optimal dose.

The aim of this study was to investigate the interactive effect of aerobic training and curcumin supplementation on  mitochondrial NRF-1 and NRF-2 gene expression of cardiomyocytes in infarction model male rats.

32 male rats were randomly divided into four groups: control, aerobic training, supplementation, and aerobic training + supplementation.  The training  and training + supplementation groups participated in an aerobic training program for 8 weeks. The training was performed on an intelligent animal electronic treadmill 5 days a week, and at this time the control and supplementation  groups did not have an training program. Also, curcumin supplementation was given to the supplementation and training + supplementation groups five days a week by gavage.  After surgery, the expression of NRF-1 and NRF-2  genes in cardiomyocytes was avaluated using real-time PCR method. Shapiro-Wilk and two-way analysis of variance were used for the analysis of data.

Both training and curcumin supplementation variables significantly increased the expression of NRF-1 and NRF-2 in cardiomyocytes.  The results also showed that there is a positive and significant interaction between two variables, so that the increase in expression of NRF-1 and NRF-2 genes in the training + supplement group was more than the other groups.

 It seems that both training and curcumin supplementation alone and in interaction with each other can increase the gene expression of some factors that stimulate mitochondrial biogenesis in cardiomyocytes of male rats with myocardial infarction.

Some hepatokines e.g. Fetuin-A, ANGPTL4 and FGF21 are considered as potential factors for type 2 diabetes disorders treatment. The aim of this study was to investigate effects of 12 weeks of aquatic exercise on some serum fetuin-A, ANGPTL4 and FGF21 levels in obese women with type 2 diabetes.

For this purpose, 44 diabetic women aged 50-60 years with a body mass index higher than 25 kg / m2 were randomly divided into two groups of control (n = 22) and water exercise (n = 22). The training group performed underwater exercises for 12 weeks three sessions a week at 75-60% of MHR. The control group followed the normal process of daily activities. Blood samples were collected before and after exercise. Fasting serum glucose, insulin, plasma hemoglobin, fetuin-A, angiopoietin-4, fibroblast growth factor-21, and lipid profile to calculate insulin resistance index. Data were analyzed using ANCOA test.

Serum levels of FBS, HbA1C, fetuin-A, ANGPTL4, fat percentage, insulin and insulin resistance in the experimental group decreased significantly after 12 weeks of water training compared to the control group (p<0.05). Also, exercise in water significantly increased FGF21 levels in the experimental group compared to the control group (p<0.05). Exercise in water significantly reduced TC, TG and LDL indices in the experimental group (p<0.05); But the increase in HDL was not significant (p = 0.21).

It seems that aquatic could reduce diabetes complications.

Diabetic cardiomyopathy is a complication of type 2 diabetes that can lead to myocardial cell autophagy through Beclin-1 and light chain 3 proteins. The aim of this study was to evaluate the effects of 8 weeks of continuous and intermittent aerobic exercise with resveratrol supplementation on Beclin-1 and LC3 gene expression in the heart tissue of diabetic male rats.

 For this purpose, 56 male Wistar rats with mean (age 40-50 weeks and weight 430-373 g) were randomly divided into 8 groups (n = 7) control (C), diabetic (D), saline (S), Resveratrol (Sup), Continuous exercise (E), Interval exercise (HIIT), Continuous exercise/Supplement (E+Sup), Intervalt exercise/Resveratrol (HIIT+Sup).  Diabetes was diagnosed by intraperitoneal injection of streptozotocin at a dose of 50 mg / kg body weight. Continuous training rats trained three days a week for 8 weeks at a speed of 15 meters per minute.  The intermittent training protocol also included 10 one-minute sets with an intensity of 50% vo2max on the treadmill and two minutes of rest between sets, starting at 14 meters per minute and increasing rapidly by two meters per minute each week.  Data were analyzed using two-way analysis of variance at the α (α ≥0.05) level.

 The results showed that Beclin-1 and LC3 in the diabetic induction group had a significant decrease compared to the healthy control group (P = 0.001). Compared with the diabetic group, the diabetic + exercise + supplement group showed a significant increase in Bcline-1 and LC3 (P = 0.001).

  Exercise combined with resveratrol supplementation can increase Beclin-1 and LC3 autophagy factors” which inhibit apoptosis and reduce heart tissue damage in diabetics.

Myocardial infarction, in addition to destroying cardiac tissue remodeling, also affects the blood homeostasis system. The purpose of the present study is to investigate the effect of eight weeks of continuous and interval training with warfarin on expression of cardiac osteopontin gene and coagulation indices (PT, PTT, INR) in male rats with myocardial infarction.

In this experimental study, 42 male rats (eight weeks old) were randomly divided to seven groups of (six in each) healthy control, myocardial infarction, myocardial infarction with (interval training, ‌continuous training, ‌warfarin, ‌interval training+‌warfarin, and ‌continuous training+‌warfarin). Duration of incremental interval training (one minute: 16-33, two minute: 10-14) m/min and incremental continues training (14-24 m/min, 10-60 minutes) was eight weeks, five sessions per week. Induction was induced by subcutaneous injection of isoproterenol in two doses of 85 mg/‌kg. 48 hours after the last training session, blood samples and heart tissue were extracted to measure the variables. Independent T-test, one-way ANOVA and Two-way analysis of variance were used to analyze the data (P<0.05).

Induction of myocardial infarction leads to increased expression of osteopontin (P=0.001), PT values (P=0.001), PTT (P=0.001) and INR (P=0.001) compared to the healthy control group. The results of Tukey test showed that PT values in myocardial infarction+warfarin group (P=0.002) and myocardial infarction+warfarin+ECT group (P=0.001) had a significant decrease compared to myocardial infarction group. There was a significant decrease in PTT values in of all groups (P<0.05) and also a significant increase in INR of the experimental groups that had received warfarin compared to the myocardial infarction group (P<0.05).

In myocardial infarction, interval and continuous training along with warfarin can control PT and PTT coagulation factors. Further studies on the replacement of osteopontin with therapeutic modalities of the present study are needed.

Inhibitory and activating mechanisms of interventions such as high intensity interval training and caffeine administration on major pathways of programmed cell death (apoptosis and autophagy) are not well understood. The aim of present study was to evaluate the effects of high-intensity interval training along with caffeine administration on Beclin-1 and Bcl-2 proteins expression in myocardium muscle of type 2 diabetic male rats.

In the present experimental study, 50 male white Wistar rats with an age range of 2-3 months were randomly divided into 5 groups of 10 rats in each group: Healthy control (C), Diabetic control (D), Diabetic with Training (D+T), Diabetic with Caffeine treatment (D+CA), Diabetic with Training and Caffeine treatment (D+T+CA). Western blot analysis was used to evaluate the cardiac muscle proteins (Bcl-2/Beclin-1).

The protein expression level of Beclin-1 was more than the C group, in D group; 201%, D+CA group; 215% and in D+CA+T group; 199% in compared to B-Actin (P=0.001). The Bcl-2 protein expression level in the experimental groups were significantly lower in comparison to the C group (P=0.001, F=73.83). As the expression level of this protein was significantly lower at around 37% in the D group compared to the C group (P=0.001). Whereas the Bcl-2 protein expression levels was significantly lower in the D+CA group and D+T+CA group compared to the C group at about 64 and 70 percent, respectively (P=0.001).

The results indicate that performed high-intensity interval training is effective in modulating the overexpression of Beclin-1 autophagic index and improving expression of Bcl-2 anti-apoptotic index. However, caffeine supplementation alone and along with high-intensity interval training were not effective in modulating of autophagic protein and improving anti-apoptotic protein.

Obesity and metabolic disorders are considered as risk factors for health and both physical activity and herbal supplements have appreciable effects on weight control. Therefore, The aim of present study was to investigate the effect of eight weeks of resistance training with green tea extract supplementation on serum levels of adiponectin and pentraxin-3 in obese men.

In an experimental experiment - with a double-blind design, 30 healthy men with an age range of 26-38 years and a body mass index of more than 30 kg / m2 were randomly divided into three groups of 10, including the green tea extract supplement group, exercise group + Green tea extract supplement and exercise group + placebo were included. The experimental subjects received circuit resistance training, which was performed three times a week. All groups were given 600 mg green tea extract supplements or placebo for eight weeks in two doses of 300 mg daily. Anthropometric indices, and blood sampling were measured before and after eight weeks of circuit resistance training. Data analysis was performed using analysis of variance with cunning measurement as a 3.2 design at a significance level of p≥0.05.

The results showed that 8 weeks of resistance training with green tea extract supplement significantly reduced body weight (p≥0.02), body mass index (p≥0.02) and waist to hip ratio (p≥0.04) in the training group with green tea extract supplement, but a significant change in levels. Serum adiponectin (p=0.06) and pentraxin-3 (p=0.27) were not observed.

It seems that consumption of green tea extract along with resistance training could be beneficial in obese males’ weight control, however; no firm conclusions can still be drawn on their concomitance.

The purpose of present study was investigating the effects of 8 weeks eccentric and concentric resistance training on Action potential conduction velocity of quadriceps muscle fibers.

30 male inactive subjects (age: 22.3±2.1 years; weight 71.3±8.6 kg and height: 1.76±0.1 m) were recruited for this controlled laboratory study. Subjects were randomly divided into two groups: the eccentric training group (No=15) and the concentric training group (No=15).  The maximal voluntary contraction (MVC) of quadriceps muscles and surface electromyography signals were recorded before and after 8 weeks of resistance concentric and eccentric training with 80% of 1RM. The multifactorial variance and Tukey Post hoc tests were used for data analysis.  

The results showed that MVC of knee extension after eccentric resistance training and concentric resistance training significantly increased (P=0.001). Also the increase in the mean power frequency and Action potential conduction velocity of muscle fibers after eccentric resistance training was significantly more than the increase after concentric resistance training (P<0.05).

The higher increase in maximum voluntary contraction of knee extension is associated with increasing the frequency of moderate strength and Action potential conduction velocity of muscle fibers after eccentric resistance training indicates better adaptation and recruitment of fast-twitch muscle fibers to eccentric resistance training.

Considering the role of hormones on depression's levels that caused by Alzheimer's disease, and also the effect of exercise training on hormone secretion levels in the body, the aim of this study was to investigate the effect of 12 weeks of aerobic exercise training on depressive behaviors and hormones levels of testosterone and corticosterone in Alzheimer's male rats.

For this purpose, 40 male Wistar rats with an average age of 8 weeks and average weight of 237±33 g were randomly divided into four groups of 10: control, exercise, Alzheimer's and exercise + Alzheimer's. To induce Alzheimer's, 3 mg/kg streptozotocin in 5 μl of sterile distilled water was injected into the ventricular region. The training protocol was performed for 12 weeks, 5 sessions/week and 30 minutes in each session at a speed of 10 m/min from the first to the 6 weeks and 12 m/min from the 7 to the 12 weeks. At the end of the training period, Sucrose preference and forced swimming tests were performed as tests for estimating depression. After completing the behavioral tests, testosterone and corticosterone levels were measured by ELISA.

The results showed that 12 weeks of exercise training significantly reduced the immobility time in the forced swimming test (P = 0.001)  and significantly increased the sucrose preference test (P = 0.001) in rats with Alzheimer's disease. Also, a period of exercise training has caused a significant increase in testosterone (P = 0.006) and a significant decrease in corticosterone (P = 0.006) in rats with Alzheimer's disease.

Aerobic exercise training on treadmill appears to be effective in treating depressive behaviors in rats with Alzheimer's disease by increasing testosterone levels and decreasing corticosterone.

Hypertensive is among the leading causes of mortality and exploring alternative strategies for its better control has ever had special importance. The aim of this study was to investigate effect of acute resistance exercise session with and without blood flow restriction (BFR) on blood pressure in pre-hypertensive and hypertensive women.

 24 volunteer subjects, were randomized into two groups (n=12) of pre-hypertensive (blood pressure: 12.5-14 mmHg, age: 54.5±1.88 years and BMI 27.0±2.01 kg/m2) and hypertensive (blood pressure: 14.5-16 mmHg, age: 55/25±2.05 years and BMI 27.51±1.93 kg/m2) patients. All three groups experienced three different sessions with a week washout interval including on control, resistance training (3 sets at 20-30% of 1RM) with BFR and resistance training (3 sets at 70% of 1RM) without BFR. Blood pressure and heart rate were recorded at resting condition, between sets rest intervals, at respectively 15, 30, 45, 60 and 120 minutes, post exercise and also at resting condition 24 hours post exercise. Data were analyzed by repeated measures analysis of variance test at the P <0.05.

There were significant falls in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) level as well as heart rate (HR) post exercise in both groups, with sharper drops observed in training with BFR session (P<0.001).

It seems that resistance training with BFR could be more beneficial to lower patients’ blood pressure.