Table of Content - Volume 14 Issue 1 - April 2020
Cardiovascular responses to isometric hand grip exercises between dominant and non-dominant hand in young males
Vanajakshi B J1, Suma H P2*
Abstract Background: Isometric hand grip exercises using hand grip dynamometer where voluntary muscle activity is associated with sympathetic outflow to cardiovascular system to increase the heart rate and blood pressure. The rise in heart rate is also due to parasympathetic withdrawal and activation of other central command. Muscles which are used frequently in daily functional activities are the forearm muscles. Handgrip strength is used as an indicator of overall muscle strength. Aims And Objectives : 1. To determine the cardiovascular responses to hand grip exercises between dominant and non dominant hand in young healthy males. 2. To observe the changes in parameters (pulse rate, systolic blood pressure and diastolic blood pressure) after doing hand grip dynamometer exercises between dominant hand and non dominant hand. Methods: 100 healthy young male medical students of age 18 -20yrs studying at, Raichur Institute of Medical Sciences, Raichur, were taken for the purpose of the study. After taking consent, linear height, Weight, Blood pressure, Pulse rate was recorded. Statically analysis was done by using mean, standard deviation, student’s t test and studied the differences of cardiovascular responses to hand grip dynamometer between dominant and non dominant hand. Base line blood pressure and pulse rate were recorded in both the arms in right handed dominant subjects. Subject was asked to grip the hand grip dynamometer using maximum force with their dominant hand for few second. The procedure repeated for three times, the maximum value of three readings was taken as the maximal voluntary contraction. Blood pressure and pulse rate were recorded. Same procedure was repeated on non dominant hand and responses were noted down. Results: 100 healthy medical students were taken for the study. Basal values of pulse rate (81.81±8.31). Systolic blood pressure (120.3±8.36). Diastolic blood pressure (78.45±6.02) in dominant hand and non dominant hand were recorded. After exercises pulse rate value was 91.05±9.02). Systolic blood pressure value was (125.5±8.13). Diastolic blood pressure value was (81.9±5.69) in dominant hand. In non dominant hand after exercise pulse rate value was (88.89±9.86). Systolic blood pressure value was (127±7.64). Diastolic blood pressure value was (80.11±5.65). There were no much significant values observed pulse rate, systolic blood pressure and diastolic blood pressure between dominant and non dominant hand. Conclussion: Study revealed that there was significant increase in systolic blood pressure and increase in diastolic blood pressure and increase in heart rate in dominant hand after handgrip exercises; however there was also significant increase in all the parameters in non dominant hand of the same individuals. When compared the parameters between dominant hand and non dominant hand there was no much change observed in all the parameters. Key Words: Isometric exercises. Blood pressure, Dominant and Non dominant hand.Dynamometer.
INTRODUCTION Hand grip strength, which can be measured easily and objectively using a dynamometer is a predictive of multiple outcomes among variety of subjects1. Isometric hand grip exercises are a form of static resistance exercise. Such exercises are characterized by a change in muscle tension while muscle length remains constant. They induce different circulatory and metabolic adjustments in the body, depending upon their types of action. As contrast to isotonic exercises, in isometric exercises, only small groups of muscles remains in contracted state, throughout the exercises, resulting in compression of blood vessels and occlusion of blood flow to the active muscle2. When creating an isometric tension there will be increase in pulse rate, systolic blood pressure and diastolic blood pressure3,4.Mitchell and associates5 and Seals et al.6 suggested that cardiovascular responses to isometric exercises are greater when larger muscle groups are involved. Blood pressure responses to isometric hand grip exercises are significantly elevated after exercises. The power of hand grip is the result of forceful flexion of all finger joints with the maximum voluntary force that the subject is able to exert under normal biokinetic conditions. Strong correlations between grip strength and various anthropometric traits, (weight, height, hand length etc.) were reported earlier(Malina et al.. 1987; Ross and Rosblad 20027). In fact, the grip strength is reported to be higher in dominant hand with right handed subjects, but no such significant differences between sides could be documented for left hander people (Incel et al.. 20028). Right and left hand grip strength was positively correlated with weight, height and body surface area (Chatterjee and Chaudhuri 19919). Studies have done to know the hand dominance on grip strength and to calculate the endurance time, however no studies have done to know the effect of isometric exercises on cardiovascular responses between dominant non dominant hands. The present study was done to assess the cardiovascular responses to handgrip exercises on dominant and non dominant hand of right handed dominant healthy medical students.
MATERIALS AND METHODS 20 healthy Medical students were analysed. 16(80%) students have shown significant differences so sample size is calculated by using the formula 4PQ/L2.Students studying at Raichur Institute of Medical Sciences were taken for the purpose of the study. The study was conducted in department of physiology during the period of October 2015 – December 2015. After informed consent, the students were asked to report to the department at morning hours. Anthropometry was conducted using standard protocol. The subject was asked to sit comfortably in a chair. The subjects were explained about the test and procedure. The base line blood pressure and pulse rate were recorded. Then the subject was asked to grip the handgrip dynamometer using maximum force with their dominant hand for a few second. The value was noted and the procedures were repeated thrice. The maximum value of the three readings was taken as the maximum voluntary contractions (MVC). Blood pressure and pulse rate was recorded. Same procedure was repeated on non dominant hand and responses were noted down. The blood pressure response was calculated as highest diastolic blood pressure during the test – Baseline diastolic blood pressure. Blood pressure response to sustained handgrip test>= 16mmhg was taken as normal. >=11-15mmhg as borderline and <=10mmhg as abnormal. Statistical analysis was carried out using GraphPad Prism software. Paired t test was carried out for before and after hand grip dynamometer exercises and unpaired t test was carried for dominant and non dominant hand. Mean values, Standard deviation of Pulse Pressure(PR), Systolic Blood Pressure(SBP), Diastolic Blood Pressure(DBP) before and after hand grip dynamometer exercise of dominant and non-dominant hand were assessed. Analysis was done at p < 0.05 with CI 95%.
RESULTS 100 healthy medical students were taken for the study. Table 1: Mean values of PR, SBP, DBP of individuals before and after exercise with Dominant Hand.
Note: (S)- Significant, (HS)- Highly Significant.
Table 2: Mean values of PR, SBP, DBP of individuals before and after exercise with Non-dominant Hand.
Note: (S)- Significant, (HS)- Highly Significant.
Table 3: Comparison of mean values PR, SBP, DBP after exercise with dominant and non-dominant hand.
Note: (S)- Significant, (HS)- Highly Significant.
Basal values of pulse rate (81.81±8.31). Systolic blood pressure(120.3±8.36). Diastolic blood pressure (78.45±6.02) in dominant hand and non dominant hand were recorded. After exercises pulse rate value was ( 91.05±9.02). Systolic blood pressure value was (125.5±8.13). Diastolic blood pressure value was (81.9±5.69) in dominant hand. In non dominant hand after exercise pulse rate value was (88.89±9.86). Systolic blood pressure value was (127±7.64). Diastolic blood pressure value was (80.11±5.65). There were no much significant values observed in pulse rate, systolic blood pressure and diastolic blood pressure between dominant and non dominant hand. Results showed that there was significant changes observed in cardiovascular responses to hand grip dynamometer exercises in both dominant hand and non dominant hand but when compared the changes between dominant and non dominant hand, there was no such statistically difference observed.
DISCUSSION Exercise is a common physical stress that can elicit cardiovascular abnormalities that are not present at rest, and it can be used to determine the adequacy of cardiac function. Human physical activity involves a combination of dynamic and static exercises. Static exercise can be characterized by increase in muscle tension with little or no change in the length of the muscle10. Isometric exercises may be used to evoke or accentuate indirect physical evidence of cardiac dysfunction due to left ventricular myocardial diseases11. Studies have shown that the magnitude of hemodynamic changes occurring during static exercise seems to depend upon the relative strength of contraction i.e. the proportion of maximal effort employed12.Therefore, the purpose of this study was to document the cardiovascular responses of subjects to different isometric handgrip exercises and hopefully to provide guidelines for safe evaluation and prescription of isometric exercises for patients suffering from cardiovascular diseases and to note any changes seen when compared between their dominant and non dominant hand.In the present study we found increase in systolic blood pressure and diastolic blood pressure and even increase in pulse rate in dominant hand of right handed person after doing isometric exercises by using hand grip dynamometer, however in left arm also the responses were increased after isometric exercises.When we compared the values of after exercises between dominant and non dominant hand there was no such significant difference was observed in systolic blood pressure and pulse rate, there was statistically significant value was observed in diastolic blood pressure. The increase in blood pressure at the onset of exercise may be due to increase in sympathetic flow. Mean arterial pressure increases suggests significant changes in either cardiac output or total peripheral resistance at the onset of isometric exercises. Increase in diastolic pressure suggests a lesser decrease in arterial pressure during diastole as the aorta supplies blood to the systemic vascular beds. There are many possible explanations for such responses. According to Sanchez et al.13 increase in sympathetic flow increases the level of circulating catecholamine’s. This study investigated changes in blood pressure and catecholamine’s response to isometric hand grip exercise at 30% MVC.Similar study was done by Saito M, Kato M, Mano T. In their study blood pressure increased significantly during MVHG(maximum voluntary handgrip) . Although the heart rate rose during MVHG, it returned to resting level during PEI. The increased MSNA(muscle nerve sympathetic activity) was less in DA exercise than the NDA, while no significant differences in heart rate and blood pressure response were observed. The results suggest that handedness seems to influence reflex sympathetic activation during muscular contraction, but has no significant effect on heart rate or blood pressure.
CONCLUSSIONS In conclusion the present study showed that 1: cardiovascular and hemodynamic responses to isometric exercises do increase in systolic blood pressure, diastolic blood pressure, and pulse rate in both dominant and non dominant hand. 2: There are no significant differences observed in cardiovascular responses when compared between dominant and non dominant hand.
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