Kjell Myhre

Effects of physical training in intermittent claudication

Mechanisms for increased claudication distance following physical training were studied in ten patients with peripheral arterial insufficiency. The exercise capacity on a bicycle ergometer increased by an average of 26% after 3--4 months of training (P less than 0.05). Neither maximum lower leg blood flow during the exercise test nor oxygen uptake at exhaustion changed significantly after training (-8% and +5%, respectively), whereas popliteal-venous O2-saturation was lower at exhaustion after the training than before (8.5 +/- 3.2 and 11.4 +/- 4.6, respectively, P less than 0.05). Anaerobic glycolysis, as evidenced by the lactate release, was also lowered after the training (P less than 0.05). In conclusion, the present study shows that the increased exercise capacity following physical training in claudicants is associated with an increased local aerobic working capacity despite a virtually unchanged blood flow. This increased aerobic exercise capacity might partly be explained by an increased O2 extraction in the lower leg during exercise.

Lower leg blood flow in intermittent claudication

Lower leg blood flow was measured at rest and both during and after graduated bicycle exercise in five healthy men and in seventeen patients suffering from various degrees of obliterating arteriosclerosis of the lower limbs. A thermodilution technique was used for flow determinations. The subject exercised in the sitting position and the work load was increased stepwise from a starting load of 100 kpm/min (100 kpm/min load increment every second minute until exhaustion). Three flow phases were depicted during and after the exercise: the aerobic phase, the phase of relative ischaemia and a postexercise phase. During exercise, lower leg blood flow increased approximately twenty times in healthy subjects, while in the arteriosclerotic subjects there was a two-fold to ten-fold increase in flow. In patients with serious distal and proximal stenoses a proximal steal phenomenon was demonstrated during submaximal and maximal exercise. A close correlation was found between maximum individual work load capacity and maximum lower leg blood flow (r = 0.71, P less than 0.001). In the patient group lower leg blood flow at a certain work load was 45% (P less than 0.001) higher in the sitting than in the supine position.

Body temperature and aspects of behavioural temperature regulation in some neonate subarctic and arctic birds

Body temperatures were measured and aspects of behavioural temperature regulation studied in neonate birds of several species brooded in subarctic/arctic areas. The studies were performed during field and laboratory conditions. Subadult body temperatures were found in all chicks in the field and also in the chicks allowed to select ambient temperatures in a thermal gradient box. It is suggested that subadult neonate body temperature in birds is a normal physiological condition connected to a lowered thermoregulatory set-point. The observation that motor coordination was not impaired even at severe hypothermia is suggested to favour survival of the chicks in cold climates.

Determination of lower leg blood flow in man by thermodilution

A thermodilution method for measuring distal femoral vein flow in man is presented. The catheter is introduced percutaneously in central direction into the popliteal vein. Tests for accuracy in vitro (r = 0.999, range of true flow 63–2600 ml/min) and in dog experiments (r = 0.994, range of electromagnetic flow measurements 110–780 ml/min) are presented and discussed in relation to the anatomical (dissections on corpses) and functional conditions in the popliteal/distal femoral vein of man. A group of normal persons [7] and of patients suffering from ischaemic lower limb disease [17] were studied at rest and during exercise on an ergometer in supine and sitting positions. In all but two, reliable measurements were obtained. In the normals, a mean resting flow of 114 ml/min (range 82–140 ml/min) was found. The individual coefficient of correlation between load and flow measurements in the normals varied from 0.80 to 0.94 during stepwise increasing load exercise. No serious complications occurred. The method...

Exercise-and post-exercise metabolism of the lower leg in patients with peripheral arterial insufficiency.

Exercise- and post-exercise metabolism were studied in the lower legs of six subjects without known arterial insufficiency and in sixteen claudicants. Lower leg blood flow was measured with a thermodilution catheter in the popliteal vein. The catheter allowed blood sampling from the calf before, during and after an exhaustive, stepwise increasing load exercise on a bicycle ergometer. A higher oxygen extraction and higher lactate release during exercise in claudicants than in normal subjects persisted in the post-exercise period (P less than 0.05). Leg arteriopoplitealvenous differences of free fatty acids (FFA) showed an inverse intergroup relationship to that of glucose. Being higher in claudicants than in normal subjects during exercise (P less than 0.05). However, net uptake of FFA was not significantly different in the groups of legs although it appeared increased relative to glucose in claudicants both during and after the exercise. Thus no statistically significant substrate preference was detected although the results suggests a preference for FFA relative to glucose in legs with arterial insufficiency. The study furthermore demonstrated the lag of exercise metabolism into the post-exercise period in such legs and a close relationship between this metabolic delay and the severity of the disease.