In 2004, a study in patients with chronic stable congestive heart failure (CHF) showed that supplementation with l-arginine taken by mouth prolongs exercise duration. It was thought this might be due to nitric oxide-induced dilation of blood vessels in peripheral areas of the body.
L-arginine is a dietary supplement that may improve the physical fitness of people with CHF. Under normal conditions, l-arginine is metabolized to nitric oxide, which helps blood vessels dilate and supply more oxygen-carrying blood to tissues. Dysfunction of the “l-arginine-nitric oxide” pathway in CHF leads to lower blood flow that partly accounts for the limited ability of these patients to exert themselves.
Now, a study published last month supports these findings. Patients with CHF who took l-arginine supplementation by mouth for 6 weeks showed the following improvements during exercise compared with CHF patients who did not.
- Average heart rate decreased during exercise and during recovery
- Blood pressure and respiratory parameters stayed constant
- Peak increase in plasma lactate was blunted (ie, more efficient energy metabolism)
These findings support ongoing l-arginine supplementation to improve patients’ physical fitness. Patients most likely to respond to l-arginine supplementation have elevated blood levels of asymmetric dimethylarginine, which acts opposite to l-arginine to inhibit nitric oxide formation.
8/2/06 21:45 JR