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Biomedical subjects

G R Cumming

Publications and source records attributed to G R Cumming.

At least 73 records · Page 4Linked to original sources
PubMed1970

Heart rate and haemodynamics after autonomic blockade in infants and children.

In order to assess the role of the autonomic system in the age differences in heart rate, propranolol 0.2 mg./kg. and atropine 30 micrograms/kg. were given to 103 infants and children during the course of heart catheterization. Mean control minute heart rate varied from 118 at age 1 year to 81 at age 16 years. Heart rate after drugs was termed intrinsic heart rate after Jose, and the mean varied from 139 at age 1 to 102 at age 16 years. After propranolol alone, mean heart rate was 120 at age 1, 71 at age 16, and after atropine corresponding rates were 162 and 128. The scatter in predicting heart rate from age was not lessened by autonomic blockade, suggesting that inter-individual variations in heart rate are not entirely dependent on different levels of autonomic function. The inverse relation between heart rate and age persisted after autonomic blockade, indicating that different levels of autonomic function are not responsible for the age differences in heart rate. The most important determinant of the heart rate after blockade was the initial control heart rate. Increases in cardiac index followed autonomic blockade in patients over 4 years of age and in patients without intracardiac shunts, while stroke index decreased, and femoral artery pressure increased 2/7 mm. Hg.

Adolescent↗
PubMed1967

A fitness performance test for school children and its correlation with physical working capacity and maximal oxygen uptake.

The Canadian Association for Health, Physical Education and Recreation fitness test (CAHPER test) composed of six items was compared to two laboratory tests of endurance fitness, physical working capacity at a minute pulse rate of 170 (PWC(170)) and maximum oxygen uptake (Vo(2) max.) in over 500 Winnipeg school children of both sexes aged 6 to 17 years. CAHPER test results were similar to the national average published by CAHPER in a test booklet. Correlation coefficients (r) of Vo(2) max. for boys with the CAHPER tests were: sit-ups .42, broad jump .69, shuttle run .50, arm hang .43, 50-yard dash .60, 300-yard run .65; for girls the r values were about half the values for the boys. Much of the correlation between CAHPER tests and Vo(2) max. or PWC(170) depended on the association of each test with body size. When multiple correlations were obtained including surface area as the first variable, the only significant factor correlating with the endurance tests was the arm hang; none of the other tests showed a significant correlation. "Physical fitness" is task-specific, so that a subject's position in the scoring scale of a fitness test depends entirely upon the test. The CAHPER test for physical fitness shows little or no correlation with standard laboratory measures of endurance in average children.

Adolescent↗
PubMed1966

Radio telemetry of the electrocardiogram, fitness tests, and oxygen uptake of water-polo players.

During competitive water polo, heart rate in six subjects was monitored by cupped plastic and silver electrodes glued to the skin. Minimum rates during the game averaged 156 beats/min.; maximum rates averaged 186 beats/min. Mean maximum rate with bicycle exercise was 188 beats/min. Maximum oxygen (VO(2) max.) with bicycle exercise of 14 water-polo players was 53.3 ml./kg. Physical working capacity (PWC 170) was 1310 kilopond metres per square metre (k.p.m./sq.m.). PWC 170 correlated well with VO(2) max. in this small group (r = 0.77).Oxygen uptake was measured at three speeds of swimming and four levels of work on a bicycle ergometer. VO(2) max. of swimming was 88% of that obtained on bicycle exercise. The slope of the oxygen uptake vs. pulse rate curves was less for the swimming than for cycling, so that for a given oxygen uptake below the maximal, pulse rate was less in the swimmers. At near-maximal swimming, respiratory quotient was 0.95 compared with 1.27 for cycling, suggesting that the swimmers were underbreathing.

Adult↗