Reversible impairment of forearm vasodilation after forearm casting

To examine whether the resumption of normal physical activity after forearm immobilization would reverse impaired vasodilation, the minimal vascular resistance was examined in six subjects who had forearm casts placed for broken forearm bones. Each subject was examined twice, once within 48 h after forearm cast removal and again approximately 29 days later. The formerly casted forearm and the opposite forearm (noncasted) were examined. Minimal vascular resistance decreased in the casted forearm from 3.0 +/- 0.4 to 2.6 +/- 0.5 mmHg.ml-1.min.100 ml (P less than 0.014). There was no change in the noncasted forearm: 2.5 +/- 0.3 vs. 2.5 +/- 0.3 mmHg.ml-1.min.100 ml. This study shows that maximal vasodilation improves with the resumption of normal physical activity and therefore demonstrates that immobilization is associated with a reduced forearm vasodilator capacity.