It is undeniable that exercise is very beneficial for our daily lives. There are a lot of benefits you can take from it and also from physical fitness articles in the book Physical Fitness. Exercise is able to ensure all your body systems to work properly. People who do not have an exercise routine have greater risk to suffer from some different ailments and diseases as they are getting older. However, establishing a exercise routine is very hard to start. Scientist have come up with target heart rate zones that can tell people whether they are at the level of exercise that is beneficial for health. These charts are based on age and are helpful but the most important thing a person can do is listen to their body. To force yourself into the pain zone because you "should" be able to do it is dangerous. If one feels they are working hard, they are. If they can't carry on a conversation without gasping for breath, they may be working too hard. The biggest downside of going at it too hard is that no one voluntarily continues a program of misery. If they want to make exercise a practical and consistent part of their life, then it needs to be enjoyable-well, at least not miserable! Exercise needs to be sustained, not sporadic, to produce the benefits of exercise. Some, who are just starting out on the adventure of exercise, may not be able to exercise for more than a few minutes at a time. This is OK. Over a few weeks they can gradually build up their exercise duration until most will be able to exercise for at least an hour at a time. Beyond intensity, the most important thing about reaping the benefits of exercise is that it needs to happen every day.