Red Light Therapy for Coronary Bypass Recovery: Scientific Evidence

Whether light delivered both into a vein and through the skin could reduce complications after heart bypass surgery was tested in a 2021 randomized controlled trial. 192 patients were randomly assigned, of whom 170 finished, split into a treated group of 82 and a control group of 88, most of them men (73 of 82 and 82 of 88), with both groups averaging 60 years of age. The skin treatment used near-infrared light at 980 nm and 200 mW, delivering 6 J/cm², while a second device sent blue light at 405 nm and 1.5 mW into a vein in the arm for 30 minutes, given 6 times across 6 days. Only the treated group showed falling blood markers of heart muscle damage over the 6 days after surgery, along with changes on heart tracings pointing to less strain on the heart muscle. Fluid around the heart, readmission, heart failure, and chest infection were all less common in the treated group, which also appeared to report less pain, though the control group had started out with more smokers and more people with high blood pressure.

Comparing 32 patients given laser treatment after heart bypass surgery against 28 who were not, a 2014 observational study tracked blood markers of heart muscle damage. A diode laser at 810 nm and 500 mW was applied on 3 successive days after surgery, over the cut through the breastbone and at points on the chest above the heart. Blood was drawn before surgery and across the 5 days afterwards, 1 hour and 12 hours after each daily treatment. Researchers found that immune cell counts and blood markers of heart muscle damage in the laser group differed meaningfully from the control group by day 5. The study authors concluded that the treatment may reduce damage to heart cells and speed tissue repair, which could shorten bed rest and disability after surgery.

90 people undergoing heart bypass surgery took part in a 2014 randomized controlled trial of LED therapy for pain and wound healing. They were split into 3 equal groups receiving LED light, a placebo device, or no device at all. The light was delivered at 620 to 660 nm and 70 mW in contact with the cut through the breastbone, at 39 mW/cm² and 1.2 J/cm² for about 2.53 minutes per session during their hospital stay. Only the LED group appeared to report meaningfully less pain when coughing on days 6 and 8 after leaving hospital, measured on both a rating scale and a pain questionnaire. 3 researchers who examined photographs of the wounds without knowing the group assignments found less redness and fewer cases of bleeding or the wound opening back up in the LED group.