تاثیر تمرینات ویبریشن کل بدن بر فشار خون، ضربان قلب و عوامل خطرزای قلبی- عروقی در دختران دارای اضافه وزن

زمینه و هدف: تمرینات ویبریشن کل بدن سازوکار جدیدی است که سبب افزایش قدرت عضلانی و متابولیسم می‌گردد. با این حال تاثیر این نوع تمرینات برعوامل خطرزای قلبی- عروقی در افراد چاق و دارای اضافه وزن به خوبی مشخص نیست. هدف از این بررسی تاثیر تمرینات ویبریشن کل بدن بر فشار خون، ضربان قلب و عوامل خطرزای قلبی عروقی در دختران دارای اضافه وزن بود.روش کار: در این مطالعه نیمه تجربی، 40 دختر دارای اضافه وزن به صورت در دسترس انتخاب و به طور تصادفی در دو گروه تجربی (تمرینات ویبریشن کل بدن) و کنترل قرار گرفتند. تمرین ویبریشن کل بدن در 30 جلسه و هر روز انجام شد. متغیرهای بیوشیمیایی در دو مرحله قبل و بعد از تمرینات اندازه گیری شد. جهت تجزیه و تحلیل داده ها از تحلیل کوواریانس (ancova) در سطح 0.05> p استفاده شد.یافته ها: نتایج نشان داد تمرین ویبریشن کل بدن موجب کاهش معنی دار میزان قند خون ناشتا (0.001=p)، کلسترول تام (0.006=p)، لیپوپروتئین کم چگال (0.000=p)، ضربان قلب (0.028=p)، شاخص توده بدنی  (0.002=p)، لیپوپروتئین پر چگال (0.047=p) و نسبت دور کمر به لگن (0.000=p) در دختران دارای اضافه وزن شد اما بر تری گلیسرید (0.852p=) و فشار خون (0.189p=) ‌تاثیر معناداری نداشت.نتیجه گیری: با توجه به نتایج، به نظر می‌رسد تمرینات ویبریشن کل بدن می‌تواند به کاهش عوامل خطرزای قلبی- عروقی در افراد دارای اضافه وزن کمک کند.

the effect of whole-body vibration on blood pressure, heart rate and cardiovascular risk factors in overweight girls

background & aims: overweight and obesity is a serious and growing health problem, that is associated with the risk of disability and increased morbidity (1). in obese people, hypertriglyceridemia and insulin resistance lead to impaired fasting glucose, hypertension, inflammation, and accumulation of visceral adipose tissue (2). these factors contribute to adverse cardiovascular outcomes due in part to cardiac autonomic dysfunction (3-5). thus, hypertension increases sympathetic balance and arterial stiffness, decreases heart rate variability, endothelial dysfunction, and ultimately increases the risk of coronary heart disease, stroke, and cardiovascular death (6). recently, whole-body vibration has been considered a potential alternative or adjunct to exercise (10). evidence suggests that whole-body vibration is associated with decreased fat accumulation and fat reduction in rats (13). these results suggest the use of wbvt in the treatment of obesity. in fact, wbvt improves body composition, muscle strength and cardiovascular function in a variety of populations, including obese people (14). in general, physical activity may reduce cardiovascular risk factors and thus reduce mortality by improving the lipid profile and thus obesity (18). therefore, there is a strong rationale for the importance of exercise in improvement programs of lifestyle to prevent or treat overweight and obesity. whole body vibration training has been suggested as a useful protocol to increase metabolism (19). however, the effect of whole-body vibration training on cardiovascular risk factors in obese and overweight people is not well understood. therefore, the present study aims to investigate the effect of whole-body vibration training (wbvt) on blood pressure, heart rate and cardiovascular risk factors in overweight girls.methods: in this semi-experimental study, 40 overweight girls were selected and randomly divided into experimental (whole-body vibration training) and control groups. whole body vibration training was performed in 30 sessions every day. biochemical variables were measured before and after training. data were analyzed with covariance analysis (ancova) at the p<0.05.results: the results showed that wbvt significantly reduced fasting blood glucose (p=0.001), total cholesterol (p=0.006), low-density lipoprotein (p=0.000), heart rate (p=0.028), bmi (p=0.002), high-density lipoprotein (p=0.047) and waist-to-hip ratio (p=0.000) in overweight girls but had no significant effect on triglyceride (p=0.852) and blood pressure (p=0.189).conclusion: the results of the present study showed that whole body vibration training significantly reduced fasting blood glucose, total cholesterol, low-density lipoprotein, heart rate, bmi, high-density lipoprotein and waist-to-hip ratio in overweight girls but had no significant effect on triglycerides and blood pressure. the findings of this study were consistent with the results of previous research (16, 20, 21). wbvt increases glycemic control by improving insulin action and regulation of glucose. it seems that lowering blood glucose following whole body vibration training is associated with increasing muscle mass. in fact, these training increase the volume of lean muscle mass, and this increase in volume by increasing glucose storage in muscle and facilitating glucose metabolism (20). the mechanism of significant changes in blood pressure and heart rate following whole-body vibration training is still unclear. in some previous findings it has been reported that significant changes in systolic blood pressure have been achieved and a significant improvement in diastolic pressure is achieved when these training are combined with other forms of training (24). increased local blood flow immediately after vibration training as well as neurophysiological changes following tonic reflection of vibration may increase elasticity and facilitate increased flexibility (30). the mechanism that reduces body fat percentage and fat profile by whole body vibration is still unknown. however, there are potential contributing factors; whole-body vibration training increase the concentration of serum free fatty acids during the recovery period (33), in addition, activate the central sympathetic nervous system (34); the key role of this system is to stimulate lipolysis in white adipose tissue. there is relationship between the activity of the central sympathetic nervous system and fat oxidation, and hypofunction of this system is a risk factor for weight gain in humans (35). also, the catabolic effect of vibration on adipose tissue can be explained by converting kinetic energy to thermal energy under friction forces (36). the present study had limitations such as lack of control over physical activity of research groups outside the study time, lack of control of genetic and congenital characteristics that affect obesity, lack of complete control of mental health conditions and lack of precise control of fatigue and sleep quality of the subjects was mentioned during the study. according to the results, it seems that wbvt can help reduce cardiovascular risk factors in overweight people.