题目

Have you ever considered starting a fitness program? Since exercise can reduce the risk（风险） of diseases, improve balance, help lose weight, better sleep habits and even make you confident, you can start a fitness program in the following steps.Test your fitness levelHow many meters can you walk or run in one minute? How much time does it take you to swim 50 meters? What is your heart rate(心率)? The data(数据) of your fitness level can help you know what activities you need.Design your fitness programYou may have begun your daily exercise. But a personal plan helps more. First, you简述医学上治疗由肾功能衰竭等疾病引起的血液中毒时，所进行的血液透析的原理。