MUSCLE BLOOD-FLOW DURING INTERMITTENT EXERCISE - COMPARISON OF THE MICRODIALYSIS ETHANOL TECHNIQUE AND XE-133 CLEARANCE

1. Local skeletal muscle blood flow was monitored using the microdialy sis ethanol technique and Xe-133 clearance during intermittent isometr ic contractions (5s on/l0s off) of the thigh at 0-60% of the maximal v oluntary isometric contraction force. 2. A linear increase in blood fl ow over a 25-fold range was detected using both Xe-133 clearance and t he microdialysis ethanol technique. 3. The median correlation coeffici ent between percentage maximal voluntary isometric contraction force a nd the ethanol outflow/inflow ratio, a marker of blood flow, was r = - 0.98 (-0.94 to -0.99) (median and range, n = 6). The corresponding cor relation coefficient for Xe-133 clearance was r = 0.97 (0.92-0.98), th e correlation coefficient between the ethanol outflow/inflow ratio and Xe-133 clearance being r = -0.92 (-0.89 to -0.94). 4. Dialysate gluco se concentration, although affected by blood flow, was not always sign ificantly correlated with blood flow changes (r = 0.70; 0.51-0.95). 5. It may be concluded that the ethanol technique provides a valid measu re of changes in local skeletal muscle blood now. The data furthermore show that a linear increase in thigh skeletal muscle blood flow exist s during the studied protocol of intermittent isometric contractions.