A lot of time people are looking for a way to stay active without running a marathon or becoming a gym rat. They want something nice and easy that they can sustain for a long period of time. There are also those who need something with less impact due to past injuries. The three man fitness alternatives that constantly get brought up are walking, swimming and cycling. They all hold health benefits, compared to being sedentary, whether minor or major.
Walking can burn approximately 255-390 per hour depending on your pace and size. Swimming can burn approximately 540-890 per hour depending on the same criteria. Finally cycling can burn approximately 360-650 per hour. Now the major caveat is the actual hour. Most people will struggle to do a full hour or even form the habit needed to make this alternative activity a benefit to one's health and fitness. For those who do use this method of training it is important that even if you begin this program only doing 15 minutes at a slow pace, you can still progress by pushing yourself to go further and faster each time.