Medical science holds that the speed of blood circulation throughout the body is inversely proportional to the speed of muscle movement. Muscle and nerves are tense and blood vessels are squeezed, which will reduce blood flow and cause local ischemia and hypoxia. When the tension of muscle and brain nerve increases by more than 60% than usual, the local blood flow can be completely interrupted. Of all diseases today, 60% to 80% can be traced back to the excessive tension of modern life.
 The option 'Many diseases of modern people are related to the tense state of life' is intended to be explained in this passage.