Abstract
Background: Chronic pain of musculoskeletal origin can cause severe and prolonged pain which, in turn, can alter the autonomic outflow and thereby cardiovascular system. Various studies have been done on this issue but the same study has not been conducted yet in the population of Eastern Uttar Pradesh, India.

Aims and Objective: This study was conducted to assess the effects of chronic pain on cardiovascular autonomic control using isometric handgrip test (IHGT) and deep breath test (DBT).

Materials and Methods: The patients (50 males of the mean age of 38 ± 2.2 years and 28 females of the mean age of 40.5 ± 2.0 years) having the pain of musculoskeletal origin with chronicity of >6 months duration and severity of >3 on visual analog scale were included in the study. The age-sex matched controls (58 males of the mean age of 35 ± 2.2 years and 28 females of the mean age of 39.6 ± 1.2 years) were also selected. The DBT and IHGT were performed, blood pressure (BP) and electrocardiography were recorded, and the heart rate (HR) was calculated.

Results: During DBT, there is a significant difference in the HR changes in the male cases versus male controls (P < 0.05), but expiration: inspiration (E: I) ratio did not show any significant changes among various groups. In IHGT, BP changes in female cases versus female controls and male cases versus female cases were found significantly different (P < 0.05) and HR changes were also significantly different in all the three groups (P < 0.05).

Conclusions: The results indicate the parasympatholytic responses in the male and female cases which are further supported by the HR changes in the IHGT. The BP responses indicate the normal sympathetic response in the female cases and subnormal response in the male cases.

Key words: Isometric Handgrip Test; Deep Breath Test; Pain; Blood Pressure; Heart Rate; Sympathetic; Parasympathetic Reactivity