The in vivo effect of low-intensity optical radiation (LIOR) on the blood of patients with unstable angina (UA) was studied. The integration of LIOR in the combined therapy of patients with UA proved to result in positive changes in the oxygen uptake system. Changes in the absorption spectra of the patients' blood samples, blood oxygenation characteristics, and the proportion of metabolic products were studied at all stages of light exposure. The absorption of LIOR by the blood was found to lead to its photomodification, which was manifested in changes of the partial pressure of blood gases, the content of oxyhemoglobin and the degree of saturation of hemoglobin with oxygen. LIOR affects the oxygen exchange in the body of patients with UA, changes the delivery and consumption of oxygen by tissues, initiates positive changes in the balance between the production of reactive oxygen intermediates, acting as physiologically active compounds, and their inhibition by antioxidant systems.
