The oxygen partial pressure (pO
_2
) 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 pO
_2
increase was noted at the beginning of exercise. This was followed by a pO
_2
decrease because of an increased O
_2
demand in the working muscle. The initial pO
_2
increase was thought to be due to the recruitment of capillaries and not the subsequently increased heart rate. At rest and during activity pO
_2
values were higher in physically active subjects than in the sedentary and the exercise induced decrease of pO
_2
values was slower and in addition to this the compensation to baseline values quicker.
