New research revealed on a BBC TV Horizon programme broadcast in February 2012, suggests it is possible to improve some measures of fitness with just 3 minutes of exercise a week. Medical journalist Dr Michael Mosley, like many people, is not a great fan of exercise for its own sake, and set out to find how little he would need to do to get fit. And he discovered some surprising facts about health benefits of HIT, or High Intensity Training. Challenging Current Thinking \"It goes against everything I was taught in medical school, and everything I have ever read since\", gasps Mosley to camera, as he completes a vigorous bout of pedalling on a stationary exercise bike while scientists look on. Mosley, who trained as a medical doctor before moving into journalism and broadcasting, introduces the one-hour programme, \"The Truth About Exercise\", by saying that what he discovered about exercise, thanks to the latest research, has challenged his view, and altered the way he lives his life. High Intensity Training A main theme of the TV programme is High Intensity Training (HIT), where you do a number of shorts bursts of intense and effortful exercise with short recovery breaks in between. HIT is not new, but has come to prominence in recent years as more researchers have looked into and measured its health benefits. There are various forms of HIT, depending on the intensity and duration of the effortful bursts, and your fitness goals. (The HIT in this article is not to be confused with another type of workout also called HIT: a strength-training made popular in the 1970s by Arthur Jones, now practised by many bodybuilders, where you work with weights and perform sets of repetitions to the point of momentary muscle failure.) Recent HIT research shows, for example, that doing ten-minute sprints on a stationary exercise bike with about one minute of rest in between, three times a week, is as good for improving muscle as many hours of less strenuous conventional long-term biking. Professor Martin Gibala and his team at McMaster University, Hamilton, Ontario, Canada, carried out a study on college students, and discoverd HIT delivers the same physical benefits as traditional endurance training, even though it takes considerably less time, and surprisingly, involves doing less exercise. Types of HIT In Gibala \'s student study, the participants had to pedal at their maximum possible effort level on a specially adapted lab bike. The thinking then was that \"all out\" was an important part of the HIT method. But then, in 2010, Gibala and colleagues published another study in The Journal of Physiology, where they showed how a less extreme form of HIT worked just as well for people whose doctors might be a bit worried about them adopting the \"all out\" method, for instance those who might be older, less fit and overweight.