Could a red light boost blood flow in leg arteries?

This study is testing whether shining a red light (670 nm) on the calf muscle for 5 minutes can increase blood flow in people with peripheral artery disease (PAD). Forty adults with PAD will receive the light treatment and an ultrasound contrast injection to measure blood flow. Two blood samples will also be taken to check for nitric oxide, a molecule that helps blood vessels widen. The goal is to see if light can trigger vasodilation, which might lead to new ways to ease leg pain during walking.