Changes in femoral artery blood flow during thermoneutral-, cold-, and contrast-water therapy.

Aim. The purpose of this study was to examine the changes in femoral artery blood flow during cold water immersion (CWI), contrast water therapy (CWT) and thermoneutral water immersion (TWI). Methods. Ten athletes came to the laboratory three times, to complete a 20-min procedure in upright position: 4 min in air (baseline), then 16-min full leg TWI (similar to 35 degrees C), CWI (similar to 12 degrees C) or CWT (2:2 similar to 12 degrees C to similar to 35 degrees C) min ratio, in a random order. Blood flow was measured every 2 min: baseline (Le. min 3 and 1) and throughout water immersion (i.e. min 1, 3, 5, 7, 9, 11, 13 and 15), using Doppler ultrasound in the superficial femoral artery, distal to the common bifurcation (similar to 3 cm), above the water and stocking. Results. Compared with baseline, blood flow was significantly higher throughout TWI (min 1 to 15: P<0.001; +74.6%), significantly lower during CWI (from min 7 to 15: P<0.05; -16.2%) and did not change during CWT (min 1 to 15). No changes in blood flow occurred between the hot and cold transitions of CWT. Conclusion. This study shows that external hydrostatic pressure (TWI similar to 35 degrees C) significantly increases femoral artery blood flow. We also show that associating hydrostatic pressure with cooling (CWI similar to 12 degrees C) decreases femoral artery blood flow after a sufficient duration, whereas associating hydrostatic pressure with alternating brief exposures to contrasted temperatures does not change femoral artery blood flow under resting conditions.