The Reference Values for Muscle Mass and Strength in Healthy Indian Adults Using Whole-Body Potassium Counter and Isokinetic Dynamometer

The study aims to define the sex‑based reference data for muscle mass and strength among healthy young Indians and to compare the data from the present study with available literature. Healthy Indian adults (n = 100) aged between 18 and 40 years were recruited. The assessment of muscle mass and strength was performed. The body cell mass (BCM), fat‑free mass, and muscle strength parameters were significantly higher among males compared to females (P < 0.001). A comparison of the current study data with the available literature showed that though BCM was comparable, Indians demonstrated a significantly lower isometric peak torque (P < 0.001 for both sexes). These findings suggest that Indians tend to have a lower muscle strength compared to the Western population, despite having a comparable BCM content.

VO2 Max in an Indian Population A Study to Understand the Role of Factors Determining VO2 Max.

VO2 max is the maximum amount of oxygen a person can consume and the value does not change despite an increase in workload. There is lack of data evaluating the impact of factors, which could affect VO2 max measurement, particularly in Indian population. The objectives of the present study were (i) to estimate VO2 max in a young healthy Indian population and to compare it with available prediction equations for Indian population (ii) to correlate time to achieve VO2 max with the relative VO2 max (iii) to assess the factors affecting the time to achieve VO2 max measurement (body composition and physical activity level). Twenty healthy adult males (18-30 years) underwent detailed anthropometry, physical activity level and modified Bruce protocol for VO2 max assessment. Breath by breath VO2, VCO2, oxygen saturation, heart rate, blood pressure were measured continuously and following exercise protocol. There was an internal validity between the estimated VO2 max and the maximum heart rate (MHR) (r=0.51, P<0.05). Respiratory rate and tidal volume significantly correlated with VO2 max P<0.01). Linear regression analysis indicated physical activity level (PAL) was a strong predictor of time to reach VO2 max. Out of the 3 prediction equations computed to estimate VO2 max, 2 equations significantly overestimated VO2 max. In Conclusion, physical activity level emerged to be a strong predictor of time to VO2 max. Time to achieve VO2 max is an important factor to be considered when determining VO2 max. There was an overestimation in the VO2 max values derived from predicted equations.

A study of stress and autonomic nervous function in first year undergraduate medical students.

Psychological stress is a risk factor for hypertension and coronary artery disease. The purpose of this study was to assess the impact of real life stressor, that of stress among first year medical students on cardiac autonomic regulation. Stress levels in 36 non-smoking, healthy first year medical students of either gender were assessed on a self-rating scale. Cardiac autonomic regulation was tested using both conventional tests and spectral analysis of heart rate variability (HRV). Nine subjects who obtained scores on the stress scale in the upper quartile were classified as the "stress" group and the rest constituted the "no stress" group (n = 27). There were no significant differences between the two groups on any of the conventional tests of autonomic nervous activity. The low frequency power in normalized units and low frequency high frequency ratio of heart rate variability in supine posture was significantly higher in the "stress" group compared to the "no stress" group. The low frequency power in normalized units was significantly positively correlated with total stress score. The changes were suggestive of a tilt in the resting cardiac autonomic balance towards increased sympathetic activity.

Effect of age and nutritional status on heart rate responses to cough and maximum handgrip.

Autonomic nerve activity can be assessed using simple bed side tests such as cough and maximum hand grip (MHG). The alterations in these tests are, however, poorly documented in physiological states. The present study aimed to uncover the effect of nutritional status and age on these tests. 93 male adults were divided into normal body mass index (BMI) (BMI; 18.5 to 25 kg/m2; young 18-30 yrs, n=28; old >60 yrs, n=25) and low BMI (BMI; <18.5 kg/m2; young 18-30 yrs, n=19; old >60 yrs, n=14) groups. The younger subjects showed a significantly higher heart rate response to cough and MHG in both normal and low BMI groups as compared to the older subjects (P<0.01). However, there were no significant differences for the heart rate responses to cough and MHG between the low and normal BMI groups either in the young or in the elderly. The data suggest that while the heart rate response to cough and MHG are useful tests of vagal activity to the heart when expected differences are large, they may be of limited use in uncovering more subtle changes.