This study found that shining red light on the abdomen was “able to induce a long lasting hypotensive effect in hypertensive rats and vasodilation by a NO dependent mechanism.” This means their blood pressure regulated and they had increase flow in their vascular system due to nitric oxide induction with red light exposure. Great reasons to shine red light into the body.
https://www.ncbi.nlm.nih.gov/pubmed/28414077