Purpose: The purpose of this study was to simultaneously measure time course changes in pressure of compression stocking and oxygenation state of the gastrocnemius muscle (MG) during passive dorsiflexion in patients who admitted to the ICU after surgery. Methods: Participants comprised five patients in post-surgical state of esophageal cancer (mean age, 59.4±6.1 years). Patients were performed exercise consisted of 10 cycles involving passive dorsiflexion and release until a few hours after surgery. Changes in oxygenated hemoglobin (oxy-Hb), deoxygenated hemoglobin (deoxy-Hb) and total hemoglobin (t-Hb) of medial belly of the MG were measured by near infrared spectroscopy. Changes in pressure of compression stocking was simultaneously measured at the lateral side of the MG. Results: The compression pressure was 20.4±1.6 mmHg at rest and increased up to 4.2±3.2 mmHg during dorsiflexion. oxy-, deoxy-, and t-Hb decreased during dorsiflexion, and recovered during release. t-Hb after 5-min passive exercise significantly decreased as compared with those before exercise. Conclusions: Increase in compression pressure during dorsiflexion may induced by changes in shape of calf. Passive exercise for 5 min might decrease muscle blood volume in patients while wearing compression stockings studies.