Investigating the effect of four weeks of isometric handgrip exercise on changes in blood flow-related vasodilation and blood pressure in women with hypertension

Master's Thesis in

Field of Physical Education and Sports Sciences - Physiology

Abstract

Investigation of the effect of four weeks of isometric handgrip sports activity on changes in blood flow-related vascular dilation and Blood pressure in women with hypertension

Hypertension plays a significant role in cardiovascular diseases and mortality of these types of diseases in the world. It seems that hypertension has a complex relationship with endothelial dysfunction. High blood pressure is significantly associated with disorders in cardiovascular function and structure, which causes damage to the heart, kidneys, brain, vessels and other organs and leads to premature death. The purpose of this research was to investigate the effect of four weeks of isometric handgrip exercise on changes in blood flow-dependent vascular dilation (FMD) and blood pressure in women with hypertension. For this purpose, in this study, 14 women with the age range of 30 to 55 years were selected based on body fat mass and the type of blood pressure medication used. The participants performed the isometric handgrip training program in 4 weeks, 3 sessions per week. Before starting the exercises and 24 hours after the last session, blood pressure and Doppler ultrasound were taken from the right brachial artery of the subjects. Data evaluation was done using the dependent T-test of the pre-test-post-test design at a significance level of P<0.05. According to the obtained results, significant changes were observed in the amount of FMD and systolic and diastolic blood pressure in the subjects group (p < 0.001, p = 0.006 and p < 0.001, respectively). In the end, the results of this study showed that handgrip isometric exercise with a positive effect on endothelial function can potentially reverse endothelial dysfunction in hypertensive individuals.

Key words: isometric exercises, changes in vasodilation dependent on blood flow, systolic and diastolic blood pressure

It is estimated that hypertension affects 1 billion people worldwide, which increases the risk of cardiovascular diseases (CVD) [1] and Increased mortality is associated, especially in the elderly, and it is well established that blood pressure increases with age. (Rafael Das Reis et al. [2], 2013). In the United States of America, there are about 77.9 million adults with hypertension, according to the statistics of the National Health and Nutrition Examination Survey (NHANES) [3] in 2007, 81.5% of these people are aware of their disease, 74.9% are under treatment, 52.5% are under control, and 47.5% are not under control. Predictions show that hypertension will increase by 7.2% from 2013 to 2030 (American Heart Association[4], 2013). Modification of lifestyle, including increasing exercise activity is recommended for the prevention and treatment of high blood pressure (Cherry Lee et al. [5], 2007).

Decreasing physical activity and excessive consumption of fats, meat, sugar, salt and smoking along with stressful life in the past decades have increased the incidence of major non-communicable diseases in human societies. Almost two-thirds of deaths in developed countries are due to these diseases. And in the countries of the Middle East, cardiovascular diseases, chronic lung diseases and diabetes form three of the first six causes of death. In Iran, these diseases are one of the main causes of death and disability. The risk factors for the occurrence of these diseases include high blood pressure, high blood fats, glucose metabolism disorders, overweight and obesity, and smoking, which is common in our country, especially in big cities.

According to the statistics listed in the list of deaths in 29 provinces of the country in 2013, the ten main causes of death in Iran were, respectively, cardiovascular diseases, accidental accidents, cancers, respiratory diseases, perinatal disorders, gastrointestinal diseases, general accidents, urinary and reproductive system diseases, endocrine and metabolic disorders, and congenital anomalies. Although this ranking will undoubtedly change in our country by 2030, the accuracy, precision and methodology of collecting national statistics is worthy of consideration (Azizi, Jangharbani, and Hatami, 2019).

In adults, systolic blood pressure of 140 mmHg or higher or diastolic blood pressure of 90 mmHg or higher is considered high blood pressure. High blood pressure is the most common cause of failure and stroke in many countries and the most common cause of kidney failure. Currently, blood pressure-lowering drugs are among the most common drugs prescribed by doctors, however, more than half of patients with high blood pressure are not treated, and blood pressure is not optimally controlled in most of those who are treated. Nevertheless, high blood pressure in the United States has decreased significantly in the past decades, which can be due to more accurate measurement and diagnosis of high blood pressure or the result of extensive measures taken for the primary prevention of cardiovascular diseases in this country. The prevalence of high blood pressure in European countries is also mentioned in the same range. The studies conducted in Iran also indicate a high prevalence of hypertension. In the latest survey of Tehran city in the Healthy Heart Project (2016), the prevalence of high diastolic blood pressure in the age range of 25 to 65 years is about 23% and high systolic blood pressure (without high diastolic blood pressure) is about 10%. This statistic emphasizes the need to pay more attention to cardiovascular risk factors and the importance of primary prevention in the country (Hatami, Razavi, Ardabili, Majlesi, Seydonuzadi and Perizadeh, 2013).

Following the development of blood pressure, controlling high blood pressure is also of particular importance so that the chance of developing complications due to blood pressure reaches its minimum value. Despite the fact that the prevention and treatment of high blood pressure has been taken into consideration and specific solutions have been provided for its treatment, which can be pointed to the availability of more than a hundred different types of blood pressure drugs, all of which have been proven to be effective, but still the reported levels for blood pressure control are disappointing. The success rate for controlling blood pressure in the United States is only 27%, which is even lower in England, France and Germany. Medical reports show that failure to control blood pressure is rooted in medication non-compliance. Unfortunately, most of the researches are limited to the inquiry in medication adherence and the findings about the decision process in the field of self-regulation of blood pressure by the patient are very few. Clearly, blood pressure control requires a certain degree of self-regulation. Self-regulation includes regular control of blood pressure, reducing salt intake, not smoking, exercising, avoiding psychological stress, eating healthy, losing weight, and regularly taking medicine as prescribed by the doctor (Brati et al., 1389).

As mentioned, one of the most important risk factors for cardiovascular diseases, It is hypertensive. The reduction of resting blood pressure in normal individuals [6] and especially in hypertensive individuals [7] is very important in terms of reducing the risk of cardiovascular problems. Sports activity can be one of the non-drug ways to prevent, reduce and treat blood pressure problems in general (Mohbi et al., 2018).

Disruption in endothelial function is one of the main factors in the development of atherosclerosis, high blood pressure and vascular disease. Coronary (CAD) [8] is considered. This case has been seen in high-risk people prone to atherosclerosis and in hypertensive patients. Also, endothelial dysfunction is an important predictor of cardiovascular events in the long term (Chang Hong et al. [9], 2012)

The endothelium of blood vessels plays an important role in regulating vessel tonicity and maintaining cardiovascular homeostasis. Dysfunction of the endothelium is related to the pathogenesis of atherosclerosis, vascular diseases and acute cardiovascular events. Blood flow-induced dilation (FMD) [10] occurs following the release of nitric oxide (NO) [11] from endothelial cells. FMD is also recently used to study the endothelial function of blood vessels as a non-invasive method.