In this study the effect of caffeine (5 mg/kg) on maximal power output, lactate, blood FFA, trigl... more In this study the effect of caffeine (5 mg/kg) on maximal power output, lactate, blood FFA, triglyceride, amylase, prolactin and cortisol hormones was examined during a 20 m. progressive shuttle-run test at the same time of day, one week apart. Subjects were twenty male, elite, long distance athletes aged between 19-30. In each of the trials, solutions were given one hour prior to testing by Appling a single blind experimental design. Statistical analysis was carried out on the relevant data using Student's T-tests. Caffeine trial was compared with the placebo. MaxVO 2 values, which reflects sportive performance of the sportsman, during exercise and all parameters before exercise were not significantly different between caffeine and placebo trials (P>0.05). After exercise (6min.), values were as fallows. Systolic blood pressure values were found to be significantly higher (P=0.02) whereas blood lactic acid values were lower (P=0.01) in the caffeine trials. Heart rate, diastolic blood pressure, FFA, triglycerides, amylase, cortisol, and prolactin concentrations were not significantly different between the trials (P>0.05). As a conclusion these results suggest that orally taken caffeine amounts of 5 mg/kg or less does not affect exercise performance and are not effective as a doping substance.
The mechanisms that regulate the development of human physiological cardiac hypertrophy remain po... more The mechanisms that regulate the development of human physiological cardiac hypertrophy remain poorly understood. The renin-angiotensin system, which is modulated by genetic polymorphism, plays an important role in the regulation of vascular tone and myocardial hypertrophy. Although a few studies have analyzed the association of angiotensin-converting enzyme (ACE) polymorphism and left ventricular (LV) hypertrophy in isotonic exercise-trained subjects who developed
Objectives In this study, we aimed to investigate the relationship between T-786C polymorphism of... more Objectives In this study, we aimed to investigate the relationship between T-786C polymorphism of the endothelial nitric oxide synthase (eNOS) gene and slow coronary flow (SCF). Study design A total of 56 patients with SCF but otherwise normal coronary arteries (mean age 48 ± 9 years) and 37 controls with normal coronary angiograms (mean age 50 ± 12 years) were enrolled in the study. Screening for the eNOS T-786C polymorphism was performed by restriction fragment length polymorphism methodology. Results In normal coronary artery and SCF groups, TT genotype frequency was 23 (62.2%) versus 22 (39.3%), TC heterozygote genotype frequency was 11 (29.7%) versus 30 (53.6%), and CC homozygote genotype frequency was 3 (8.1%) versus 4 (7.1%), respectively (P = 0.07). In dominant model statistical analysis, total CC and CT genotype frequency in control and study groups was found to be 14 (37.3%) versus 34 (60.7%), respectively (P = 0.025). A positive correlation was found between the mean thrombolysis in myocardial infarction frame count and C allele in patients with SCF (r = 0.21, P = 0.043). Conclusion We concluded that the T-786C polymorphism of eNOS gene might be a risk factor for the SCF.
Previous studies examining whether polymorphisms (G894T, 4b/a, and T786C) in the endothelial nitr... more Previous studies examining whether polymorphisms (G894T, 4b/a, and T786C) in the endothelial nitric oxide synthase (eNOS) gene are associated with ischemic stroke have yielded conflicting results. We performed a meta-analysis to investigate the potential association between these three eNOS gene polymorphisms and ischemic stroke risk. We searched databases until April 30, 2012 and used fixed or random effects models to estimate the pooled odds ratios (ORs). We analyzed 34 case-control data sets from 33 publications involving 5261/5823 cases/controls for G894T, 4295/4682 for 4b/a, and 2698/3254 for T786C polymorphisms. For Asian populations, all models showed significantly increased risk of ischemic stroke for the G894T (dominant model: OR = 1.58; 95% CI, 1.30-1.91; P = 0.000) and 4b/a polymorphisms (dominant model: OR = 1.46; 95% CI, 1.25-1.71; P = 0.000), even after Bonferroni correction (because 0.000 < 0.017). In white populations, the aa genotype seemed to be protective for ischemic stroke, as indicated by the recessive model (OR = 0.44; 95% CI, 0.22-0.87; P = 0.019). In Asian populations, the T786C polymorphism was significantly associated with ischemic stroke, as found using the dominant (OR = 1.17; 95% CI, 1.02-1.34; P = 0.025) and additive models (OR = 1.18; 95% CI, 1.05-1.33; P = 0.006). Our comprehensive meta-analysis ascertains that the G894T, 4b/a, and T786C polymorphisms are associated with ischemic stroke risk in Asians. A possible contrasting role of the 4b/a polymorphism in ischemic stroke was indicated in white populations.
Increased coronary artery disease (CAD) risk is well established in diabetes mellitus (DM). Parao... more Increased coronary artery disease (CAD) risk is well established in diabetes mellitus (DM). Paraoxonase (PON) enzyme is known to have protective effects on lipid peroxidation. This study aimed to investigate the changes in PON activity levels with duration of DM as well as the role of PON activity in progression of CAD. Eighty-four consecutive diabetic patients (mean age 58 years, 46 men) who underwent coronary angiography for diagnostic purposes were examined. Before the angiography, fasting venous blood samples were taken for PON enzyme activity, thiobarbituric acid reactive substances (TBARS), and routine biochemical parameters. Severity and extent of coronary atherosclerosis were scored numerically using the Gensini scoring system. The population was divided into three groups according to Gensini score: Group 1, mild CAD; Group 2, moderate CAD; Group 3, severe CAD. Group 1 had higher PON levels and shorter DM duration than those of Group 3. Gensini score was significantly correlated with, PON activity (r = -0.361) and apo-AI (r = -0.375). TBARS (r = -0.290) and the duration of DM (r = -0.336) also showed a significant correlation with PON activity levels. Also, multivariate linear regression and Pearson correlation analyses showed that PON activity (P = 0.04), apo-AI levels (P = 0.01), and the duration of DM (P = 0.003) were significantly associated with Gensini score. Paraoxonase activity decreases parallel to DM duration. The lack of protective effect of PON enzyme on lipid peroxidation may be a factor in acceleration of CAD in DM.
BACKGROUND Physical activity influences energy metabolism in human subjects by increasing activit... more BACKGROUND Physical activity influences energy metabolism in human subjects by increasing activity-induced energy expenditure and resting metabolic rate for several hours after exercise. Effects of exercise on circulating thyroid hormone values remain controversial. We have investigated the effect of acute aerobic exercise on thyroid hormone values. MATERIALS/METHODS The effect of different intensity levels of acute aerobic exercise on thyroid hormones was investigated in 60 male well-trained athletes by performing bicycle ergometer at 45% (low intensity), 70% (moderate intensity), and 90% (high intensity). These intensities were selected according to their maximum heart rate (MHR). At each intensity level, heart rate, blood lactic acid, serum total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) and thyroid stimulating hormone (TSH) values were measured. RESULTS The results of this study show that exercise performed at the anaerobic th...
BACKGROUND Metabolic syndrome (MetS) is a leading risk factor for coronary artery disease (CAD) i... more BACKGROUND Metabolic syndrome (MetS) is a leading risk factor for coronary artery disease (CAD) in women. Reduced paraoxonase 1 (PON1) activity may play a role in the pathogenesis of atherosclerosis through increased susceptibility to lipid peroxidation in patients with MetS. AIM To examine whether there is a relationship between serum PON1 activity and MetS in women. METHOD The study group consisted of 54 women with MetS. The NCEP ATP III guidelines were used to define MetS. The control group consisted of 65 women without MetS and CAD. All patients from the MetS group underwent coronary angiography. RESULTS The PON1 activity and salt-stimulated PON1 activity were not significantly altered in women with MetS when compared to controls (p = 0.902, p = 0.877, respectively). There was no significant difference in PON1 activity (p = 0.159), and salt-stimulated PON1 activity (p = 0.139) between diabetics and non-diabetics. In the MetS group, patients with CAD (n = 16) had significantly re...
Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte... more Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte function. We investigated the NOS3-786T>C polymorphism in chronic heart failure (CHF) and its effects on long-term mortality. Ninety-one patients with CHF who were referred to the Department of Cardiology of Siyami Ersek Cardiovascular and Thoracic Surgery Center for cardiopulmonary exercise testing between April 2001 and January 2004 and 30 controls were enrolled in this study. Patient were followed prospectively for a period of 1 to 12 years. Patients and controls were divided into three groups: TT, TC and CC, according to their NOS3-786T>C polymorphism. We noted that there was no significant difference in the genotype distribution between patients and controls. There was also no significant difference in endothelial nitric oxide synthase (eNOS) gene polymorphism between ischemic HF and nonischemic HF. During the follow-up period, 61 (67%) deaths occurred. The nonsurvivor group ...
The renin-angiotensin system has a very important role in coronary thrombosis and restenosis. Pla... more The renin-angiotensin system has a very important role in coronary thrombosis and restenosis. Plasma angiotensin converting enzyme (ACE) activity is associated with an insertion/deletion polymorphism in the gene coding for ACE. It is known that there is a strong correlation between ACE DD and atherosclerosis. However, little has been documented about its role in venous graft failure. The objective of this study was to investigate the relationships among the ACE gen polymorphism and long-term vein graft occlusion. The study population consisted of 87 consecutive white patients with symptomatic coronary artery disease in the previous month, who had had aorto-coronary bypass surgery (ACBS) more than 5 years back and who underwent coronary angiography for diagnostic purposes. On the same day of angiography, 10 mL whole blood was taken for ACE gene insertion/deletion (I/D) polymorphism. Mean age of the patients was 64.4 +/- 8.6 years, and 71 (82%) of the patients were men. The average AC...
The aim of this study was to investigate the effects of acute or habitual exercise on visual evok... more The aim of this study was to investigate the effects of acute or habitual exercise on visual evoked potentials (VEP). The study group consisted of 9 female and 7 male volleyball players and the control group contained 9 female and 7 male students who were not involved in any sportive activity. The N75, P100, and N145 latency and amplitudes were measured before and after exercise. Intragroup comparison was made to evaluate the acute effects and intergroup comparison for the chronic effects of exercise. Significant differences were noted between athletes and the sedentary subjects in terms of pre-exercise left-N145 latencies and amplitudes and left-P100 amplitudes. Right-eye N145 latencies of inactive female subjects obtained before and after exercise were also statistically different. The results suggest that acute and habitual exercise affects the VEP responses independent from the body temperature and other physiological parameters. Small sized pre-exercise P100 amplitudes in the athletes can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system. Visual evoked potentials maybe used as neurophysiological criteria in defining the performance of an athlete.
Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography hav... more Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography have been used widely to predict functional capacity but diastolic filling is affected by various factors. Tissue Doppler imaging (TDI) that records systolic and diastolic velocities within the myocardium and at the corners of the mitral annulus, has been shown to provide additional information about regional and global LV function. The goal of this study was to examine whether TDI-derived parameters add incremental value to other standard Doppler echocardiographic measurements in predicting exercise capacity. The study enrolled 59 consecutive patients with stable congestive heart failure (CHF). The etiology of heart failure was coronary artery disease in 42 patients and dilated cardiomyopathy in 17. Twenty-three age-matched healthy subjects were recruited as controls. Conventional echocardiographs and TDI were obtained. Early (Ea) and late (Aa) diastolic and systolic (Sa) mitral annulus velocities, the Ea/Aa and E/Ea ratios, were measured by pulsed wave TDI placed at the septal side of the mitral annulus and results were compared with results of cardiopulmonary exercise testing. Systolic and early diastolic velocities of mitral annulus were decreased and the E/Ea ratio was increased in the restrictive group as compared to controls (P = 0.02, P = 0.03, P < 0.001, respectively) but there was no significant difference in late diastolic velocity and the Ea/Aa ratio between the restrictive group and controls. The average peak VO2 of the patients were 14.9 +/- 4.9 ml/min per kg. Achieved peak VO2 of the patients with E/Ea ratio <or=7.5 was 17.4 +/- 5 vs 12.2 +/- 3 ml/min per kg for those with E/Ea >7.5 (P < 0.001). Interestingly, the patients with the nonrestrictive pattern and E/Ea ratio >7.5 had reduced exercise capacity, as did the group with restrictive LV filling patterns (12.8 +/- 3.3 vs 12.9 +/- 4.0 ml/min per kg, P = 0.9). Similarly, there was no significant difference in the mean exercise capacity between the patients with a nonrestrictive pattern vs restrictive pattern with E/Ea ratio <or=7.5 (16.1 +/- 5.0 vs 15.4 +/- 5.1 ml/min per kg, P = 0.78). Univariate analysis demonstrated that the peak Sa (r = 0.30, P = 0.03), peak Ea (r = 0.38, P = 0.004) and peak Aa (r = 0.35, P = 0.009) correlated significantly with maximum exercise capacity. No relationship was observed between the Ea/Aa ratio and peak VO2 (r = -0.09, P = 0.48). By multivariate analysis, including age and heart rate, the E/Ea ratio was found to be an independent prognostic factor at peak VO2 (P < 0.001. In contrast, the comparison of the maximum transmitral early diastolic velocity and the mitral annulus TDI velocity, that is E/Ea ratio, had strong correlation with peak VO2 (r = -0.46, P < 0.001). Receiver operating characteristic (ROC) analysis was performed for prediction of limited exercise capacity from the E/Ea ratio. An E/Ea ratio <or=7.5 was able to predict peak VO2 <or=14 ml/min per kg with a sensitivity of 84% and a…
BACKGROUND: Physical activity influences energy metabolism in human subjects by increasing activi... more BACKGROUND: Physical activity influences energy metabolism in human subjects by increasing activity-induced energy expenditure and resting metabolic rate for several hours after exercise. Effects of exercise on circulating thyroid hormone values remain controversial. We have investigated the effect of acute aerobic exercise on thyroid hormone values. MATERIALS/METHODS: The effect of different intensity levels of acute aerobic exercise on thyroid hormones was investigated in 60 male well-trained athletes by performing bicycle ergometer at 45% (low intensity), 70% (moderate intensity), and 90% (high intensity). These intensities were selected according to their maximum heart rate (MHR). At each intensity level, heart rate, blood lactic acid, serum total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) and thyroid stimulating hormone (TSH) values were measured. RESULTS: The results of this study show that exercise performed at the anaerobic threshold (70% of maximum heart rate, lactate level 4.59 ± 1.75 mmol/l) caused the most prominent changes in the amount of any hormone values. While the rate of T4, fT4, and TSH continued to rise at 90% of maximum heart rate, the rate of T3 and fT3 started to fall. CONCLUSIONS: Maximal aerobic exercise greatly affects the level of circulating thyroid hormones.
In this study the effect of caffeine (5 mg/kg) on maximal power output, lactate, blood FFA, trigl... more In this study the effect of caffeine (5 mg/kg) on maximal power output, lactate, blood FFA, triglyceride, amylase, prolactin and cortisol hormones was examined during a 20 m. progressive shuttle-run test at the same time of day, one week apart. Subjects were twenty male, elite, long distance athletes aged between 19-30. In each of the trials, solutions were given one hour prior to testing by Appling a single blind experimental design. Statistical analysis was carried out on the relevant data using Student's T-tests. Caffeine trial was compared with the placebo. MaxVO 2 values, which reflects sportive performance of the sportsman, during exercise and all parameters before exercise were not significantly different between caffeine and placebo trials (P>0.05). After exercise (6min.), values were as fallows. Systolic blood pressure values were found to be significantly higher (P=0.02) whereas blood lactic acid values were lower (P=0.01) in the caffeine trials. Heart rate, diastolic blood pressure, FFA, triglycerides, amylase, cortisol, and prolactin concentrations were not significantly different between the trials (P>0.05). As a conclusion these results suggest that orally taken caffeine amounts of 5 mg/kg or less does not affect exercise performance and are not effective as a doping substance.
The mechanisms that regulate the development of human physiological cardiac hypertrophy remain po... more The mechanisms that regulate the development of human physiological cardiac hypertrophy remain poorly understood. The renin-angiotensin system, which is modulated by genetic polymorphism, plays an important role in the regulation of vascular tone and myocardial hypertrophy. Although a few studies have analyzed the association of angiotensin-converting enzyme (ACE) polymorphism and left ventricular (LV) hypertrophy in isotonic exercise-trained subjects who developed
Objectives In this study, we aimed to investigate the relationship between T-786C polymorphism of... more Objectives In this study, we aimed to investigate the relationship between T-786C polymorphism of the endothelial nitric oxide synthase (eNOS) gene and slow coronary flow (SCF). Study design A total of 56 patients with SCF but otherwise normal coronary arteries (mean age 48 ± 9 years) and 37 controls with normal coronary angiograms (mean age 50 ± 12 years) were enrolled in the study. Screening for the eNOS T-786C polymorphism was performed by restriction fragment length polymorphism methodology. Results In normal coronary artery and SCF groups, TT genotype frequency was 23 (62.2%) versus 22 (39.3%), TC heterozygote genotype frequency was 11 (29.7%) versus 30 (53.6%), and CC homozygote genotype frequency was 3 (8.1%) versus 4 (7.1%), respectively (P = 0.07). In dominant model statistical analysis, total CC and CT genotype frequency in control and study groups was found to be 14 (37.3%) versus 34 (60.7%), respectively (P = 0.025). A positive correlation was found between the mean thrombolysis in myocardial infarction frame count and C allele in patients with SCF (r = 0.21, P = 0.043). Conclusion We concluded that the T-786C polymorphism of eNOS gene might be a risk factor for the SCF.
Previous studies examining whether polymorphisms (G894T, 4b/a, and T786C) in the endothelial nitr... more Previous studies examining whether polymorphisms (G894T, 4b/a, and T786C) in the endothelial nitric oxide synthase (eNOS) gene are associated with ischemic stroke have yielded conflicting results. We performed a meta-analysis to investigate the potential association between these three eNOS gene polymorphisms and ischemic stroke risk. We searched databases until April 30, 2012 and used fixed or random effects models to estimate the pooled odds ratios (ORs). We analyzed 34 case-control data sets from 33 publications involving 5261/5823 cases/controls for G894T, 4295/4682 for 4b/a, and 2698/3254 for T786C polymorphisms. For Asian populations, all models showed significantly increased risk of ischemic stroke for the G894T (dominant model: OR = 1.58; 95% CI, 1.30-1.91; P = 0.000) and 4b/a polymorphisms (dominant model: OR = 1.46; 95% CI, 1.25-1.71; P = 0.000), even after Bonferroni correction (because 0.000 < 0.017). In white populations, the aa genotype seemed to be protective for ischemic stroke, as indicated by the recessive model (OR = 0.44; 95% CI, 0.22-0.87; P = 0.019). In Asian populations, the T786C polymorphism was significantly associated with ischemic stroke, as found using the dominant (OR = 1.17; 95% CI, 1.02-1.34; P = 0.025) and additive models (OR = 1.18; 95% CI, 1.05-1.33; P = 0.006). Our comprehensive meta-analysis ascertains that the G894T, 4b/a, and T786C polymorphisms are associated with ischemic stroke risk in Asians. A possible contrasting role of the 4b/a polymorphism in ischemic stroke was indicated in white populations.
Increased coronary artery disease (CAD) risk is well established in diabetes mellitus (DM). Parao... more Increased coronary artery disease (CAD) risk is well established in diabetes mellitus (DM). Paraoxonase (PON) enzyme is known to have protective effects on lipid peroxidation. This study aimed to investigate the changes in PON activity levels with duration of DM as well as the role of PON activity in progression of CAD. Eighty-four consecutive diabetic patients (mean age 58 years, 46 men) who underwent coronary angiography for diagnostic purposes were examined. Before the angiography, fasting venous blood samples were taken for PON enzyme activity, thiobarbituric acid reactive substances (TBARS), and routine biochemical parameters. Severity and extent of coronary atherosclerosis were scored numerically using the Gensini scoring system. The population was divided into three groups according to Gensini score: Group 1, mild CAD; Group 2, moderate CAD; Group 3, severe CAD. Group 1 had higher PON levels and shorter DM duration than those of Group 3. Gensini score was significantly correlated with, PON activity (r = -0.361) and apo-AI (r = -0.375). TBARS (r = -0.290) and the duration of DM (r = -0.336) also showed a significant correlation with PON activity levels. Also, multivariate linear regression and Pearson correlation analyses showed that PON activity (P = 0.04), apo-AI levels (P = 0.01), and the duration of DM (P = 0.003) were significantly associated with Gensini score. Paraoxonase activity decreases parallel to DM duration. The lack of protective effect of PON enzyme on lipid peroxidation may be a factor in acceleration of CAD in DM.
BACKGROUND Physical activity influences energy metabolism in human subjects by increasing activit... more BACKGROUND Physical activity influences energy metabolism in human subjects by increasing activity-induced energy expenditure and resting metabolic rate for several hours after exercise. Effects of exercise on circulating thyroid hormone values remain controversial. We have investigated the effect of acute aerobic exercise on thyroid hormone values. MATERIALS/METHODS The effect of different intensity levels of acute aerobic exercise on thyroid hormones was investigated in 60 male well-trained athletes by performing bicycle ergometer at 45% (low intensity), 70% (moderate intensity), and 90% (high intensity). These intensities were selected according to their maximum heart rate (MHR). At each intensity level, heart rate, blood lactic acid, serum total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) and thyroid stimulating hormone (TSH) values were measured. RESULTS The results of this study show that exercise performed at the anaerobic th...
BACKGROUND Metabolic syndrome (MetS) is a leading risk factor for coronary artery disease (CAD) i... more BACKGROUND Metabolic syndrome (MetS) is a leading risk factor for coronary artery disease (CAD) in women. Reduced paraoxonase 1 (PON1) activity may play a role in the pathogenesis of atherosclerosis through increased susceptibility to lipid peroxidation in patients with MetS. AIM To examine whether there is a relationship between serum PON1 activity and MetS in women. METHOD The study group consisted of 54 women with MetS. The NCEP ATP III guidelines were used to define MetS. The control group consisted of 65 women without MetS and CAD. All patients from the MetS group underwent coronary angiography. RESULTS The PON1 activity and salt-stimulated PON1 activity were not significantly altered in women with MetS when compared to controls (p = 0.902, p = 0.877, respectively). There was no significant difference in PON1 activity (p = 0.159), and salt-stimulated PON1 activity (p = 0.139) between diabetics and non-diabetics. In the MetS group, patients with CAD (n = 16) had significantly re...
Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte... more Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte function. We investigated the NOS3-786T>C polymorphism in chronic heart failure (CHF) and its effects on long-term mortality. Ninety-one patients with CHF who were referred to the Department of Cardiology of Siyami Ersek Cardiovascular and Thoracic Surgery Center for cardiopulmonary exercise testing between April 2001 and January 2004 and 30 controls were enrolled in this study. Patient were followed prospectively for a period of 1 to 12 years. Patients and controls were divided into three groups: TT, TC and CC, according to their NOS3-786T>C polymorphism. We noted that there was no significant difference in the genotype distribution between patients and controls. There was also no significant difference in endothelial nitric oxide synthase (eNOS) gene polymorphism between ischemic HF and nonischemic HF. During the follow-up period, 61 (67%) deaths occurred. The nonsurvivor group ...
The renin-angiotensin system has a very important role in coronary thrombosis and restenosis. Pla... more The renin-angiotensin system has a very important role in coronary thrombosis and restenosis. Plasma angiotensin converting enzyme (ACE) activity is associated with an insertion/deletion polymorphism in the gene coding for ACE. It is known that there is a strong correlation between ACE DD and atherosclerosis. However, little has been documented about its role in venous graft failure. The objective of this study was to investigate the relationships among the ACE gen polymorphism and long-term vein graft occlusion. The study population consisted of 87 consecutive white patients with symptomatic coronary artery disease in the previous month, who had had aorto-coronary bypass surgery (ACBS) more than 5 years back and who underwent coronary angiography for diagnostic purposes. On the same day of angiography, 10 mL whole blood was taken for ACE gene insertion/deletion (I/D) polymorphism. Mean age of the patients was 64.4 +/- 8.6 years, and 71 (82%) of the patients were men. The average AC...
The aim of this study was to investigate the effects of acute or habitual exercise on visual evok... more The aim of this study was to investigate the effects of acute or habitual exercise on visual evoked potentials (VEP). The study group consisted of 9 female and 7 male volleyball players and the control group contained 9 female and 7 male students who were not involved in any sportive activity. The N75, P100, and N145 latency and amplitudes were measured before and after exercise. Intragroup comparison was made to evaluate the acute effects and intergroup comparison for the chronic effects of exercise. Significant differences were noted between athletes and the sedentary subjects in terms of pre-exercise left-N145 latencies and amplitudes and left-P100 amplitudes. Right-eye N145 latencies of inactive female subjects obtained before and after exercise were also statistically different. The results suggest that acute and habitual exercise affects the VEP responses independent from the body temperature and other physiological parameters. Small sized pre-exercise P100 amplitudes in the athletes can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system. Visual evoked potentials maybe used as neurophysiological criteria in defining the performance of an athlete.
Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography hav... more Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography have been used widely to predict functional capacity but diastolic filling is affected by various factors. Tissue Doppler imaging (TDI) that records systolic and diastolic velocities within the myocardium and at the corners of the mitral annulus, has been shown to provide additional information about regional and global LV function. The goal of this study was to examine whether TDI-derived parameters add incremental value to other standard Doppler echocardiographic measurements in predicting exercise capacity. The study enrolled 59 consecutive patients with stable congestive heart failure (CHF). The etiology of heart failure was coronary artery disease in 42 patients and dilated cardiomyopathy in 17. Twenty-three age-matched healthy subjects were recruited as controls. Conventional echocardiographs and TDI were obtained. Early (Ea) and late (Aa) diastolic and systolic (Sa) mitral annulus velocities, the Ea/Aa and E/Ea ratios, were measured by pulsed wave TDI placed at the septal side of the mitral annulus and results were compared with results of cardiopulmonary exercise testing. Systolic and early diastolic velocities of mitral annulus were decreased and the E/Ea ratio was increased in the restrictive group as compared to controls (P = 0.02, P = 0.03, P < 0.001, respectively) but there was no significant difference in late diastolic velocity and the Ea/Aa ratio between the restrictive group and controls. The average peak VO2 of the patients were 14.9 +/- 4.9 ml/min per kg. Achieved peak VO2 of the patients with E/Ea ratio <or=7.5 was 17.4 +/- 5 vs 12.2 +/- 3 ml/min per kg for those with E/Ea >7.5 (P < 0.001). Interestingly, the patients with the nonrestrictive pattern and E/Ea ratio >7.5 had reduced exercise capacity, as did the group with restrictive LV filling patterns (12.8 +/- 3.3 vs 12.9 +/- 4.0 ml/min per kg, P = 0.9). Similarly, there was no significant difference in the mean exercise capacity between the patients with a nonrestrictive pattern vs restrictive pattern with E/Ea ratio <or=7.5 (16.1 +/- 5.0 vs 15.4 +/- 5.1 ml/min per kg, P = 0.78). Univariate analysis demonstrated that the peak Sa (r = 0.30, P = 0.03), peak Ea (r = 0.38, P = 0.004) and peak Aa (r = 0.35, P = 0.009) correlated significantly with maximum exercise capacity. No relationship was observed between the Ea/Aa ratio and peak VO2 (r = -0.09, P = 0.48). By multivariate analysis, including age and heart rate, the E/Ea ratio was found to be an independent prognostic factor at peak VO2 (P < 0.001. In contrast, the comparison of the maximum transmitral early diastolic velocity and the mitral annulus TDI velocity, that is E/Ea ratio, had strong correlation with peak VO2 (r = -0.46, P < 0.001). Receiver operating characteristic (ROC) analysis was performed for prediction of limited exercise capacity from the E/Ea ratio. An E/Ea ratio <or=7.5 was able to predict peak VO2 <or=14 ml/min per kg with a sensitivity of 84% and a…
BACKGROUND: Physical activity influences energy metabolism in human subjects by increasing activi... more BACKGROUND: Physical activity influences energy metabolism in human subjects by increasing activity-induced energy expenditure and resting metabolic rate for several hours after exercise. Effects of exercise on circulating thyroid hormone values remain controversial. We have investigated the effect of acute aerobic exercise on thyroid hormone values. MATERIALS/METHODS: The effect of different intensity levels of acute aerobic exercise on thyroid hormones was investigated in 60 male well-trained athletes by performing bicycle ergometer at 45% (low intensity), 70% (moderate intensity), and 90% (high intensity). These intensities were selected according to their maximum heart rate (MHR). At each intensity level, heart rate, blood lactic acid, serum total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) and thyroid stimulating hormone (TSH) values were measured. RESULTS: The results of this study show that exercise performed at the anaerobic threshold (70% of maximum heart rate, lactate level 4.59 ± 1.75 mmol/l) caused the most prominent changes in the amount of any hormone values. While the rate of T4, fT4, and TSH continued to rise at 90% of maximum heart rate, the rate of T3 and fT3 started to fall. CONCLUSIONS: Maximal aerobic exercise greatly affects the level of circulating thyroid hormones.
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