Biomedical subjects

Viswanath Unnithan

Publications and source records attributed to Viswanath Unnithan.

3 recordsLinked to original sources

PubMed2004

Responses of children with cerebral palsy to arm-crank exercise in the heat.

PURPOSE: In response to passive heating, adults with hemispheric brain infarction demonstrate lower skin temperatures (Tsk) and higher sweating rates (SR) on the affected side. It is unknown whether children with similar conditions demonstrate a similar response and whether this response is advantageous to defending body temperature during exercise in the heat. The purpose of this study was to determine whether children with spastic cerebral palsy (CP) demonstrate less thermal strain than healthy peers during short (10 min each) bouts of arm cranking, a mode of exercise where metabolic rate can be matched between the two groups. METHODS: Eleven young people (8.3-18.3 yr) with spastic CP and 11 individually matched (body size, age, and maturity) healthy controls (CON) performed 3 x 10-min arm-cranking bouts (40 rpm) in 35 degrees C, 50% RH. Body mass, metabolic and heart rate (HR) responses, and body temperatures were periodically measured. Individuals within each CP-CON pair worked at the same intensity (0.55 +/- 0.18 W.kg-1 body mass). Data were analyzed using a repeated measures ANOVA (alpha = 0.05). RESULTS: Subjects with CP showed no difference from CON in metabolic and HR responses, or SR (as inferred from body mass changes corrected for fluid intake and output). There were also no differences between the groups in the rectal temperature change from room temperature (21-23 degrees C). The increase in Tsk from room temperature, however, was slightly (0.6 degrees C) but significantly lower (P < 0.0001; 95% CI = 0.5-0.7 degrees C) in the subjects with CP compared with CON. CONCLUSION: Subjects with CP demonstrate thermal strain responses similar to CON during upper-body exercise at relatively low intensities for short duration in a warm climate.

Adolescent↗

PubMed2004

Responses of children with cerebral palsy to treadmill walking exercise in the heat.

PURPOSE: When metabolic rate during arm-cranking in the heat is equated between children and adolescents with cerebral palsy (CP) and matched controls (CON), there are no relevant intergroup differences in heat strain. The metabolic rate, however, is known to be higher in CP during treadmill walking. The purpose of this study was to determine if during treadmill walking in the heat, the higher oxygen uptake (VO2), and thus greater metabolic heat production in those with CP would result in greater heat strain compared with able-bodied, matched CON. METHODS: Ten boys and girls (10.3-16.3 yr) with spastic CP and 10 individually matched (age, body size, biological maturity, gender, race) healthy CON performed 3 x 10-min treadmill walking bouts in 35 degrees C, 50% RH. Body mass, metabolic variables, heart rate (HR), body temperatures, and rating of perceived exertion (RPE) were periodically measured. Individuals within each CP-CON pair walked at the same speed and slope (0.9 +/- 0.4 m x s(-1), 3.3 +/- 0.6%). RESULTS: Steady-state VO2 during walking, body temperatures, and HR were all higher in the CP group compared with CON. VO2 was on average 40% higher, rectal temperature was 0.4 degrees C (99% CI = 0.1-0.6 degrees C) higher and HR (during the final minute of each exercise bout) was 37 beats x min(-1) (99% CI = 19-56 beats x min(-1)) higher. There were no differences between the groups in sweating rate (as inferred from body mass changes corrected for fluid intake and output) or in RPE. CONCLUSION: The subjects with CP demonstrated greater thermal strain than CON during treadmill walking where they require more metabolic energy and thus produce more metabolic heat than CON.

Adolescent↗

PubMed2002

Left ventricular response to dynamic exercise in young cyclists.

PURPOSE: The purpose of this study was to compare cardiac physiological and dimensional responses to exercise in highly trained young male cyclists (mean age 13.7 +/- 1.0 yr) with those of nontrained boys. METHODS: Ventricular systolic and diastolic dimensions were measured by two-dimensional echocardiography, and stroke volume was estimated by Doppler echocardiography during a progressive maximal upright cycle test. RESULTS: At rest, the cyclists demonstrated larger left ventricular dimensions relative to body size than the nonathletes. Maximal stroke index and cardiac index were significantly greater in the cyclists. The pattern of stroke volume response to exercise was similar in the two groups, with an early rise and then plateau to exhaustion. Left ventricular diastolic dimension increased slightly at onset of exercise and then gradually declined as workload increased in both groups. CONCLUSION: Factors responsible for the greater maximal stroke volume in young endurance athletes involve those variables that contribute to resting left ventricular diastolic filling (preload).

Adolescent↗