Objective Post exercise hypotension (PEH) is well known, but the locals PEH and its mechanism for PEH is unclear at present.

Methods Twenty young males were enrolled to explore the mechanism of post exercise hypotension (PEH) after 3 min elbow flexion and extension exercise of right arm. The bilateral arm blood pressure (BP) and heart rate (HR) were measured with two electronic BP monitor (Omron HEM-7112) before and immediately (0), 5, 10, 15, 20 and 30min after exercise. The bilateral brachial artery internal diameter (ID) and peak systolic flow velocity (PSV) and end diastolic flow velocity (EDV) were measured by Doppler techniques before, immediately and 10min after exercise.

Results The baseline BP, ID, PSV and EDV were similar between two arms. The SBP and DBP significantly increased immediately after exercise in the left arm, however, significant DBP decrease was seen in the right arm. During the recovery duration, bilateral SBP curves overlapped well, but the DBP curve of right arm kept lower than that of left arm. Although the bilateral PSVs significantly increased immediately after exercise, the PSV was significantly higher in right arm than in left arm (164.1 ± 54.3 vs 123.3 ± 33.4 cm/s, p < 0.05). No significant change on diameter and EDV was observed after exercise in the two arms.

Conclusions Post exercise hypotension on DBP only occurs in the exercised arm. The resistance decline of local vascular bed is the responsive factor for the DBP decrease in the exercised arm.