Unit 7 HealthPersonal viewBody mattersFitness trainer and writer Frank Sutton sees a lot of unfit people at the fitness centre where he works — and many of them are people in their teens or even younger. Here, he has some advice for his younger readers, and their parents.It’s Monday morning. At school, you’re walking upstairs to your first lesson. You are talking with two of your friends about a good Clint Eastwood film you saw on TV last night, but after you climb the stairs to your classroom, you’re out of breath and have to stop talking. You’re so glad to reach your classroom on the third floor.What’s going on? You don’t smoke, you don’t drink alcohol, you’re not really overweight, and you always thought you were fit and healthy, but obviously you’re not. What is the problem? Research in the UK shows that you’re not getting enough “extreme exercise,” especially if you’re a girl. The average 50-year-old British man is probably fitter than the average 15-year-old British girl.What is “extreme exercise”? It’s any activity that increases your heart rate and the amount of oxygen that your muscles burn. Fitness experts say that just twenty minutes of extreme exercise a day is enough. It improves your health, keeps your weight down, reduces stress and makes you sleep better. Of course, you still have to eat the right amount of the right food to keep fit.Now, don’t think that this means that you must become a fitness fanatic and give up everything you enjoy in life. You don’t have to do a sport like long-distance running or mountaineering, and you really do not have to buy an expensive fitness machine. You don’t even need to go to a fitness centre. Instead, here are three simple activities that anybody can do.Firstly, cycle to school. If this is not possible, then try to use your bike whenever you can. Secondly, if you go to school by bus, why not get off the bus two or three stops early and walk the rest of the way? Finally, never use lifts or moving staircases; use the stairs.The alternative — minimal activity — is not good. Although teens think they’ll live for ever, experts say that young people who are unfit may have serious health problems like a bad heart in later life.So, when are you going to get active? Today?