RESPIRATORY FUNCTION, CARDIOVASCULAR DIMENSIONS AND WORK CAPACITY IN BOYS WITH BRONCHIAL ASTHMA

Abstract. Twenty boys with bronchial asthma, aged 8-13 years, were studied with regard to the size of their respiratory and circulatory organs and to their exercise tolerance. The boys were divided into two groups (A and B) depending on the severity of their subjective symptoms. Normal values were found for TLC, VC and FRC in both groups, whereas the group with the most severe asthma had a slightly increased RV. In both groups THb, blood and heart volumes were normal. A quite normal relationship between these variables was observed as well as with work capacity (W₁₇₀ and V _O2 max) with no intergroup differences. Respiratory rate was lower and ventilation was increased in group B, both in submaximal and maximal exercise. Thus, tidal volume in maximal exercise exceeded 50 per cent of vital capacity in this group. These boys also had the highest blood lactate concentration at submaximal and maximal exercise. In half of the boys asthma-like attacks were elicited by the exercise. The symptoms subsided without treatment shortly after work. The frequency and intensity of attacks were similar in the two groups.     

TOTAL BODY POTASSIUM FAT FREE WEIGHT AND MAXIMAL AEROBIC POWER IN CHILDREN WITH ANOREXIA NERVOSA

ABSTRACT. Body Composition and aerobic work performance have been studied in 5 boys and 10 girls suffering from anorexia nervosa. The average ages of the two groups of children were 15.4 (boys) and 15.2 (girls) years respectively. Measurements of body composition included height, weight ( W ), body potassium (⁴⁰K), skinfold thickness (SFT) at triceps and subscapularis, blood volume (BV) and femoral condylar and radioulnar breadths. From these measurements estimates of fat free weight (FFW), skeletal weight (S) and lean body mass (LBM) were made. Work performance was assessed by measurement of the maximal aerobic power (V_O2 max). The patients had lost on average 26 % of their former body weight. The boys had on average >7 % of their body weight as fat compared with >9 % in the girls. However, the loss of weight was not solely due to loss of body fat, but could also be ascribed to a decrease in soft fatfree tissue. LBM or FFW could be estimated as well from SFT as from ⁴⁰K. V_O2 max averaged 1.43 1/min (35.1 ml/kg/min) in the anorexic boys and 1.24 1/min (33.2 ml/kg/min) in the girls and was associated with FFW and LBM. However, Vo, max was lower in relation to LBM than in healthy children of the same age. Thus it was suggested that the emaciation in anorexia is directly attributable to loss of both fat and muscle and accounts in part for the reduction of aerobic power observed. However, an important factor may be the debilitating effect of starvation on the patient, particularly in its advanced and later stages, which reduces his/her level of habitual physical activity.     

LIMB CIRCULATION IN ANOREXIA NERVOSA

ABSTRACT. Blood flow, skin temperature and blood pressure of the lower limbs and the effect of indirect, radiant heat on calf blood flow and leg skin temperature was determined in sixteen children with anorexia nervosa (group A) and fourteen healthy children (group H) of the same age and body height. Calf blood flow was measured by venous occlusion plethysmography. Arm blood pressure was obtained by tourniquet and toe pressure and digital plethys-mograms by a strain-gauge. Skin temperature was measured with a thermocouple. In group A calf blood flow was about 50–60 % lower than the mean values observed in group H and a marked difference was maintained after the heat load. Skin temperature of the knees and toes were higher in group H. Systolic arm blood pressure and toe pressure were on the average 20 mmHg and 13 mmHg lower in group A. It is suggested that there is a heat-conserving, selective peripheral vasoconstriction in the anorexic patients.     

LONG-TERM EFFECT OF PREVIOUS SWIMTRAINING IN GIRLS. A 10-YEAR FOLLOW-UP OF THE "GIRL SWIMMERS"

ABSTRACT. Thirty girls, studied in 1961 after 2.5 years of intensive swimtraining, were the subject of a follow-up for ten years. When last examined, seven and ten years after the original study, all the girls had given up swimtraining. The increased values for vital capacity observed in 1961 remained unchanged, but residual volume, functional residual capacity and total lung capacity showed small increases even after corrections for body growth. Such increases are, however, normal in these years. Heart volume which was high originally, was found to be lower ten years later, although mean values were still higher than normal. The decrease seen from 1961 to 1971 could mainly be ascribed to a decrease in the subjects with the largest hearts originally. Both total hemoglobin and blood volume decreased to normal values in relation to body size. Maximal oxygen uptake, though, fell from 2.80 1/min (51.4 ml/kg × min) to 2.18 1/min (36.4 ml/kg × min) ten years later. It is suggested that the functional capacity of the cardiovascular system declined more markedly than its dimensions.     

CIRCULATORY ADAPTATION IN THE THERMOREGULATION OF FULLTERM AND PREMATURE NEWBORN INFANTS

Blood flow measurements by venous occlusion plethysmography were performed on 131 sleeping healthy fullterm newborns at various external temperature conditions. The peripheral circulation varies among different individuals, but a definite relationship between ambient temperature and the rate of peripheral circulation could, nevertheless, be established. Different series of observations on exposure to acute changes of temperature conditions on a further 46 newborn infants allow the following conclusions: The control of peripheral circulation in relation to the temperature of the surroundings is reflex in nature and independent of the local effects of a cold stimulus. Circulatory changes are quantitatively prominent and do not support the view that thermolability in the newborn is due to a deficient thermocontrol of the cutaneous circulation. The circulatory thermoreflex operates even during the first day of life and is as prominent in premature infants as in fullterm infants. The importance of these observations in relation to other mechanisms deciding heat loss and thermogenesis in the newborn is briefly discussed.     

CARDIORESPIRATORY FUNCTION IN COMPETITIVE ENDURANCE RUNNERS AGED 12-16 YEARS COMPARED WITH ORDINARY BOYS

ABSTRACT. Thirty-four male elite endurance runners aged 12-16 years and 56 ordinary boys of the same age were studied in cross-sectional age group. At the age of 12-14 years, there were only a few differences between the runners and the controls: the runners weighed less, were leaner and had higher V0₂ max/kg body weight. The runners' good competitive performance could not be explained by a superior aerobic power at that age. In the age group of 16-year-olds, additional major differences were found: significantly higher VO₂ max (4.05 I/min, 66 ml/min/kg), W₁₇₀ (214 W, 3.5 W/kg), vital capacity (5,31 I), maximal expiratory volume (153 I/min), lower resting heart rate (62 beats/min) and larger heart volume (792 ml and 453 ml/m² BSA) in the runners. In this respect our runners resembled adult endurance athletes. No differences could be observed in any age group as to height, hemoglobin concentration, blood pressure and maximal heart rate. The differences at the age of 16 years are either training effects or due to a selection of certain "endurance runner types".     

A FIVE-YEAR FOLLOW-UP STUDY ON CARDIORESPIRATORY FUNCTION IN ADOLESCENT ELITE ENDURANCE RUNNERS

ABSTRACT. It is not known whether the superior cardiorespiratory function in adolescent athletes is attributed to the effects of training or to genetic disposition. We re-examined 6 elite endurance runners and 7 boys with ordinary physical activity 5–6 years after the first examination. At the age of 14 years the two groups did not differ as regards height, weight, percent body fat and lean body mass (LBM). The runners had slightly superior cardiorespiratory characteristics but, with the exception of lower resting and maximal heart rates (HR) in the runners, the differences were not statistically significant. At the age of 19–20 years the runners had significantly higher maximal oxygen uptake (VO₂ max) per kg body weight (74 vs. 61 ml/min/kg), VO₂ max/LBM (85 vs. 74 ml/min/kg LBM), calculated work at a heart rate of 170 beats/min (W₁₇₀) per kg body weight (3.9 vs. 2.7 W/kg), W₁₇₀/LBM (4.5 vs. 3.3 W/kg LBM), larger relative heart volume (HV) (472 vs. 369 ml/m²) and lower resting HR (52 vs. 68 beats/min) than the controls. The runners also displayed greater increases in the growth-corrected percentage changes in cardiorespiratory variables, but the differences did not reach statistical significance. We conclude that the relative VO₂max, W₁₇₀ and HV values in the runners had increased as a result of a prolonged endurance training.     

BICYCLE ERGOMETER TESTS ON BUILDING APPRENTICES AGED 15–19

A work test on a bicycle ergometer was carried out on 82 Swedish boys aged 15 to 19. The heart rates were recorded, both at the submaximal loads of 600 and 900 kpm/min and at the maximal work load. Maximal aerobic power was predicted from submaximal work loads and maximal heart rate. The heart rates obtained show decreasing values with increasing age at a given work load. This is partly ascribed to physical growth, and partly to some training effect noticeable in the older boys who have completed one year of building apprenticeship.     

EFFECT OF PHYSICAL TRAINING ON ADOLESCENTS WITH SEVERE MOTOR HANDICAPS

The case material consisted of 17 pupils at the Norrbacka Institute Schools. Cerebral palsy (CP) was present in 7 cases (mediam age 19 years), and paraplegia of other origin-chiefly myelomeningocele-in 10 (median age 17 years). All had severe motor but not mental handicaps, and had to use a wheel-chair for their daily activities. Physical training was carried out for 30 minutes twice a week for 6 weeks, concurrently with the ordinary gymnastics. It consisted of fast wheel-chair driving, exercising with medicine balls and dumb-bells, and levering movements in a wheel-chair and on parallel bars. Exercise tests were made on an ergometer bicycle for arm work; the loads were submaximal for all pupils, and also maximal for 8 in the paraplegia group. Identical submaximal tests were carried out before and after the training period, together with determination of the oxygen uptake, heart rate, blood lactate concentration and roentgenological heart volume. In the CP group, the blood lactate concentration was lower after training than before it. In the paraplegia group, significantly lower values were recorded after training for oxygen uptake, heart rate and blood lactate. No change in heart volume was detected in either group. In the 8 pupils in the paraplegia group who could perform maximal work, a 40% increase was noted after training. The better training results in the paraplegia group can be explained by the more severe handicap in the CP group, in which the arms were also involved in most cases. The heart rate during training was an average 140 beats/min in the paraplegia group, but only 115 beats/min in the CP group. The results show that these severely handicapped adolescents were able to improve their working capacity, despite training being of fairly mild intensity and carried out during a relatively short period. This implies that the ordinary gymnastic lessons were inadequate for improving the pupils' working capacity, and should therefore be complemented by a training programme of the type described. A better working capacity is highly desirable for their performance at school, as well as during their activity of daily living. It is concluded that this type of training should be included in the conventional habilitation programme for children and adolescents with motor handicaps of this type.