How Does Isometric Handgrip Exercise Affect Blood Pressure Recordings And If Gender Influences The Response To Isometric Handgrip Test In Normotensives?

Abstract

Introduction: Isometric Handgrip Test is a physiological test which causes contraction mainly resulting in change in tension of the muscle with little change in the length. Earlier studies have shown that blood pressure and heart rate responses to isometric exercises are influenced by the force of contraction, the size of contracting muscle and the length of time contracted. Despite the pattern of cardiovascular response to most forms of exercise remaining similar in both genders, the magnitude of response varies.
Aim: This present study was done to see the blood pressure changes after isometric hand grip exercise and also to evaluate if the changes were different in both the genders.
Materials and method: 75 healthy normotensive students, 39 males and 36 females were selected after obtaining informed consent from them from Silchar Medical College and Hospital, Assam, and the ethical clearance from the Institutional Ethics Committee was obtained. The present study was a cross sectional study. The instrument used was a metallic hand grip dynamometer for Isometric Hand Grip test. Inclusion criteria -Age group between 18-35 years of both genders, blood pressure less than or equal to 120/80 mm Hg, females non pregnant and with regular menstrual history. Blood pressure was recorded in non dominant arm in seated position at rest. MVC (maximum voluntary contraction) was obtained by asking them to exert a maximal effort on hand grip dynamometer. Three such readings were taken after three minutes rest in between. The greater of the three was taken as MVC. They were asked to grip the dynamometer and maintain the pressure on dynamometer for 2 min at 30% of maximal voluntary contraction (MVC) and the blood pressure was recorded from the nonexercising arm just prior to release of hand grip at 2 minutes. Then the recordings were compared and analysed with the resting blood pressure in both the genders.
Statistical analysis: it was done using Ms Exel and SPSS.
Results: the mean age of males was 21.68yrs and mean age of the females were 20.78 yrs. The data indicate significant height and weight differences between males and females, while BMI and age are similar. A highly significant change in SBP is observed from baseline to 2 minutes after IHG indicating that IHG has a strong effect on increasing SBP. There is also a highly significant change in DBP and MAP after 2 minutes of IHG showing a significant rise in DBP and MAP due to IHG. Also it was found that a statistically significant higher resting SBP in males compared to females. After 2 minutes of Isotonic Hand Grip exercise, gender-based differences in the hemodynamic parameters are evident primarily in SBP (highly significant p= 0.002) and MAP (p=0.01).
Conclusion: This study indicated the existence of gender differences in the blood pressure responses to isometric handgrip exercise. A highly significant change in SBP is observed from baseline to 2 minutes after IHG. Further studies can be done for early detection of risk of hypertension from the blood pressure response to IHG.