Intramuscular oxygen partial pressure in the healthy during exercise.

The oxygen partial pressure (pO2) in the anterior tibial muscle was measured in n=12 (6 physically active and 6 sedentary) apparently healthy subjects. This was the first time a flexible micro catheter with an outer diameter of 0.45 mm was used during skeletal muscular activity in men. A two level tread mill test which is used in the diagnosis of peripheral arterial occlusive disease was chosen to induce physical stress. In the healthy volunteers a pO2 increase was noted at the beginning of exercise. This was followed by a pO2 decrease because of an increased O2 demand in the working muscle. The initial pO2 increase was thought to be due to the recruitment of capillaries and not the subsequently increased heart rate. At rest and during activity pO2 values were higher in physically active subjects than in the sedentary and the exercise induced decrease of pO2 values was slower and in addition to this the compensation to baseline values quicker.