Researchers studied about 600 patients by following their recovery from open heart surgery for 17 months after their operations. Afternoon surgery produced fewer major complications such as acute heart failure. In a follow up study patients were divided into 2 groups. Some to receive morning, others to receive afternoon surgery. They discovered that the level of troponin, a measure of heart muscle damage, was significantly different in the afternoon group. Conclusion is that the genetic mechanism that protects tissue under stress functions differently in the afternoon and may prove to be more beneficial for the patient.