The effects of upper and lower body exercise on blood supply to the lower extremities were investigated in patients with peripheral arterial occlusive disease (PAOD) by measurements of transcutaneous oxygen tension (tcPO2) and Doppler ankle pressure (DAP). Twenty patients with PAOD (PAOD group) and 10 subjects without PAOD (control group) performed treadmill test (TT), recumbent cycle ergometry (CE), and rowing ergometry (RE) with a fixed seat. The tcPO2 was registered on the calf and DAP was measured at the end of each step of CE and RE. The walking distance in TT of the control group was not limited (> 1000 m), whereas that of the PAOD group was 161 m in median. In the control group there was no significant difference of performance between CE (125 +/- 33 W) and RE (111 +/- 24 W), whereas in the PAOD group, performance was lower in CE (72 +/- 31 W) than in RE (102 +/- 28 W) (P < 0.01). DAP of controls increased during both CE (136 to 165 mmHg) and RE (170 to 213 mmHg), whereas the DAP of the PAOD group decreased during CE (from 85 to 44 mmHg) and remained relatively constant during RE (113 to 101 mmHg). In controls, tcPO2 did not distinctly change during TT (70 to 66 mmHg) and increased during CE (58 to 73 mmHg) and RE (69 to 82 mmHg), whereas in the PAOD group, tcPO2 decreased during TT (66 to 33 mmHg) and CE (50 to 22 mmHg) and remained almost unchanged in RE (64 to 60 mmHg). A hyperbolic relationship was found between tcPO2 and DAP. In conclusion, during upper body exercise, blood supply to the lower extremities in patients with PAOD was not affected, whereas lower body exercise led to exhaustion of the functional reserve of blood supply. Because of a hyperbolic relationship between tcPO2 and DAP, tcPO2 remained relatively constant if blood supply was sufficient, but in disturbed blood supply a small change of DAP was accompanied by a great change of tcPO2. Therefore, in critical ischemia the change of tcPO2 was more sensitive than that of DAP.