If you can't face the gym more than once a week, the latest research could be welcome news.

Experts say that intense exercise sessions could equate to the same as a whole week's worth of exercise... in just one hour.

Known as interval training, this high-intensity exercise was originally developed for Olympic athletes and was thought to be too strenuous for ordinary folk.

But recent studies of older people and those with health problems have suggested that thousands more could benefit from such an exercise regime.

Jan Helgerud, from the Norwegian University of Science and Technology, told The Telegraph: "High-intensity interval training is twice as effective as normal exercise.

"This is like finding a new pill that works twice as well... we should immediately throw out the old way of exercising."

Interval training involves working hard but for only a few minutes at a time, with regular rest periods between 'intervals'.

Research has shown that, when compared to those with a normal exercise routine, interval training can double endurance, improve oxygen use and strength and even increase speed.

However, experts advise that people should consult a doctor before trying a new fitness regime, since much of the research has involved young, healthy adults.

But, as Jan Helgerud, says: "I'm much more afraid of people not exercising at all. Inactivity is what's killing us."

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