Accumulation of Fluid in Exercising Skeletal Muscle

Lymph flow from, and volume changes in, muscles during exercise were recorded simultaneously. During exercise there occurs an outward filtration at an initially steady rate. This filtration gradually diminishes and finally ceases. Under the experimental conditions used lymph flow was very small compared with the rate of outward filtration. The capillary filtrate accumulated in the muscle. The amount of fluid accumulated varied with the work load. The factors limiting outward filtration are discussed. The most important limiting factors seem to be gradually rising tissue pressure, and to some extent changes in colloid osmotic pressure on either side of the capillary wall.