Biomedical subjects

Y Bhambhani

Publications and source records attributed to Y Bhambhani.

7 recordsLinked to original sources

PubMed1991

Physiological effects of hydrogen sulfide inhalation during exercise in healthy men.

Occupational exposure to hydrogen sulfide (H2S) is prevalent in a variety of industries. H2S when inhaled 1) is oxidized into a sulfate or a thiosulfate by oxygen bound to hemoglobin and 2) suppresses aerobic metabolism by inhibiting cytochrome oxidase (c and aa3) activity in the electron transport chain. The purpose of this study was to examine the acute effects of oral inhalation of H2S on the physiological responses during graded cycle exercise performed to exhaustion in healthy male subjects. Sixteen volunteers were randomly exposed to 0 (control), 0.5, 2.0, and 5.0 ppm H2S on four separate occasions. Compared with the control values, the results indicated that the heart rate and expired ventilation were unaffected as a result of the H2S exposures during submaximal and maximal exercise. The oxygen uptake had a tendency to increase, whereas carbon dioxide output had a tendency to decrease as a result of the H2S exposures, but only the 5.0 ppm exposure resulted in a significantly higher maximum oxygen uptake. Blood lactate concentrations increased significantly during submaximal and maximal exercise as a result of the 5.0 ppm exposure. Despite these large increases in lactate concentration, the maximal power output of the subjects was not significantly altered as a result of the 5.0 ppm H2S exposure. It was concluded that healthy young male subjects could safely exercise at their maximum metabolic rates while breathing 5.0 ppm H2S without experiencing a significant reduction in their maximum physical work capacity during short-term incremental exercise.

Administration, Inhalation↗

PubMed1991

The effects of task preference on performance during purposeful and nonpurposeful activities.

This study examined the number of repetitions, increase in heart rate, increase in blood pressure, and rating of perceived exertion of subjects performing the most-preferred and least-preferred tasks from a predetermined list under purposeful and nonpurposeful conditions. Twenty healthy women completed the four experimental tests in random order for a period of 10 min each. The results indicated that there was no significant interaction (p greater than .05) between task choice and condition, thus implying that the subjects' performance was not influenced by task preference regardless of whether the activity was purposeful or nonpurposeful. Comparisons between the purposeful and nonpurposeful conditions revealed that the increase in heart rate and rating of perceived exertion were significantly higher (p less than .05) during nonpurposeful activity for both the most-preferred and the least-preferred tasks. On the basis of these results, it is recommended that therapists use purposeful, or goal-directed, activities in their practice, even if they are unable to provide their patients with a choice of therapeutic tasks.

Adult↗

PubMed1989

The effects of acute exercise on pulsatile LH release in high-mileage male runners.

Evidence suggests that acute exercise and endurance training has a suppressive effect on the hypothalamic-pituitary-gonadal (HPG) axis in men and women. To determine if training and acute exercise influence the neuroendocrine regulation of the HPG axis in men we examined pulsatile LH release in six male endurance runners with a training volume of at least 80 km per week, and compared this with values in six age-matched sedentary controls. Blood samples were obtained through an indwelling i.v. cannula from the subjects at 15-min intervals for 6 h following 24 h without significant physical activity and again in the runners, following 60 min of running at a speed equivalent to 5% below the anaerobic threshold. Mean LH pulse frequency and amplitude, as well as areas under the LH pulses and total LH curve, were calculated but only the mean post-exercise area under the total LH curve area was significantly lower than basal values (P less than 0.05) following exercise compared with the resting values in runners. Other measures of LH release did not change with acute exercise. Basal and pre-exercise testosterone levels were also measured and found to be at the lower end of normal men. The mean pre-exercise serum testosterone levels were significantly higher than basal levels. Mean testosterone levels, mean pulse amplitude, and mean area under the LH curve were significantly lower in resting runners than in the controls. The data suggest that exercise induces a general lowering of LH levels but does not inhibit LH pulsatile release. An anticipatory increase in serum testosterone occurred before exercise.

Exercise↗

PubMed1989

Ankle and wrist weights: their effect on physiologic responses during treadmill running.

This study examined the effects of ankle and wrist weights on acute physiologic responses during treadmill running. Eight physically active young men completed eight running tests at their predetermined "most comfortable" speeds with zero, 1.6, 3.2, and 4.8 kg of additional weight equally distributed on the ankles or wrists. Energy expenditure and heart rate increased as a linear function of the additional weight placed at both anatomic locations. The magnitudes of these responses were significantly higher with the weights at the ankles than at the wrists, and were independent of the strength and endurance of the pertinent muscle groups involved in overcoming the additional weight. Blood lactate concentrations tended to increase during the loaded runs. However, the values were not significantly different from those observed during control (zero load) runs. Perceived exertion increased significantly over the control value when the heaviest weights were placed at the ankles and wrists. Since ankle and wrist weights increase training intensity and energy expenditure during treadmill running, they may result in greater increases in cardiovascular fitness and greater weight loss than would be realized by training without their use.

Adult↗

PubMed1985

Ventilatory thresholds during a graded exercise test.

38 healthy male volunteers were administered a graded exercise test during which selected respiratory gas exchange variables were monitored. In each case, two distinct ventilatory thresholds were observed. The first threshold was detected by the power output at which the VE/VO2 ratio and FEO2 reached a minimum. The mathematical relationship between these two variables was such that at power outputs above this threshold, hyperventilation with respect to oxygen consumption had to occur. The second threshold was detected by the power output at which the VE/VCO2 ratio reached a minimum and the FECO2 reached a maximum. These two variables were related in a manner such that at power outputs above this threshold, hyperventilation with respect to carbon dioxide production had to occur.

Differential Threshold↗

PubMed1985

The effects of three training intensities on VO2 max and VE/VO2 ratio.

This study examined the effects of three training intensities on the maximum oxygen uptake (VO2 max) and ventilatory equivalents for oxygen (VE/VO2 ratio) and carbon dioxide (VE/VCO2 ratio) at submaximal and maximal workloads. Forty males, classified as high or low fit according to their relative VO2 max, were assigned to one of four subgroups: a control group that did not train; a continuous training group that trained at an oxygen uptake that was 10% above that at which the VE/VO2 ratio reached a minimum; another continuous training group that trained at an oxygen uptake that was mid-way between that at which the VE/VO2 ratio reached its minimum and maximum; and an interval training group which trained at 100% VO2 max. The work:rest intervals were one minute each. Initial fitness level and total training power output for the eight week program was equalized in each group in the two fitness categories. The results indicated that both fitness categories responded similarly to the three training intensities. The training groups showed significant but equivalent increases in the VO2 max, but no significant changes in the max VE/VO2 or max VE/VCO2 ratios. The submaximal VE/VO2 and VE/VCO2 ratios were significantly lowered, primarily as a result of a significantly lowered, primarily as a result of a significant decrease in the ventilation volume. It was concluded that continuous and interval training programs wee equally effective in improving VO2 max and submaximal ventilatory efficiency, regardless of initial fitness level, provided the total amount of work completed was equalized. Such training programs, however, were unable to modify the maximal ventilatory efficiency in either fitness category.

Carbon Dioxide↗

PubMed1985

Metabolic and cinematographic analysis of walking and running in men and women.

The purposes of this study were to compare the total metabolic costs and gait patterns of walking and running at self-selected, comfortable speeds in males and females. Total oxygen consumption was used to determine the metabolic cost, and cinematographic analysis was used to study the gait patterns of walking and running a distance of 1 km in 12 male and 12 female subjects. No significant sex difference was observed for the speed, vertical lift per stride, and total vertical lift per km of distance walked. Females ran at a significantly slower speed than males (P less than .01), but no significant sex difference was observed for the vertical lift per stride or total vertical lift per km of distance run. In both sexes, the gross and net energy costs of running were significantly greater (P less than .001) than those of walking when values were expressed as kcal . kg-1 . km-1 or cal . kg-1 . stride-1. No significant sex difference was observed in the gross or net metabolic cost of walking, whereas during running, the gross and net metabolic costs in kcal . kg-1 . km-1 were significantly higher (P less than .05) in females than in males. It was hypothesized that this sex difference was due to the cumulative effect of several factors which were biomechanical and metabolic in nature.

Adult↗