The objective of this study was to investigate the extent to which internal risk factors for the development of decubitus ulcers are related to the blood flow response following the relief of a pressure load. There were 122 nursing home patients (43 men, 69 women, mean age: 81 ± 8 years; range: 60-97). The following potential, internal risk factors for the development of decubitus ulcers were assessed: chronic disorders (diabetes mellitus, cardiovascular disease [congestive heart failure, history of myocardial infarct or angina pectoris] and cerebrovascular accident), fever, blood pressure, nutritional status, serum hemoglobin concentration, and serum urea and serum creatinine concentrations. Skin temperature response (latency time and total response time) was measured following relief of a 100 kPa test pressure. The presence of cardiovascular disease, cerebrovascular accident, poor nutritional condition, high serum urea and male gender showed a significant relationship with an impaired blood flow response. The delayed latency found showed a similarity to the so-called "no-reflow phenomenon." The association of cardiovascular disease and a cerebrovascular accident with a delay in the blood flow response may result from endothelial damage. A poor nutritional condition may be associated with a deficit of scavengers of oxygen-derived free radicals. The presence of free radicals may damage endothelium during reperfusion, thus influencing the blood flow response. The association of high serum urea with delayed vasodilatation may theoretically be explained by the association of serum urea and impaired kidney functioning, since the kidney is an important organ in the production of vasoactive substances. Serum urea can also be considered a measure for nutritional condition. Gender may function as a substitute for other, unmeasured factors that are related to blood flow response.