Get fit in four minutes - could this be the answer to fitness for busy people?

Experts just can't make up their minds on how to keep us fit and healthy. It seems every week there's a new and usually contradictory theory on how we can boost our health and slim our waistlines.

But a new study out today has some findings we could really get behind - as it suggests we could shave our workout times from hours in the gym to just four minutes, three times a week, and still get all the same health benefits.

Researchers at the Norwegian University of Science and Technology in Trondheim found that 12 minutes of high intensity exercise a week, split over three sessions, had almost the same benefits as longer workouts in term blood pressure and glucose levels.

Experts have suggested this could be a way to encourage overweight couch potatoes to get fit, but it struck a cord with us as four minutes seems like a much more managable amount of time to give up three days a week than the 30 minutes a day we're usually recommended. For those of us juggling busy jobs, social lives and family commitments - could this be the answer?

[Walking vs HIIT - which is better for your health?]

Possibly. But, and there's always a but, in the study, cholesterol and body fat levels were found to respond better to those put on a longer exercise programme - of 16 minutes three times a week. So if you're also looking to lose weight and tone up you might have to give up a little more time.

Perhaps a bigger but is that high intensity workouts were recently blamed by Andrew Marr for the stroke he experienced in January, after he overdid it on the rowing machine.

So which is better? Long walks or short bursts of extreme activity?

For a start, Andrew Marr's stroke was due to a combination of factors, not, as he glibly put it, a single workout. He was overworking and overcompensating with irregular but very strenuous exercise, and hadn't noticed the warning signs of two mini-strokes that had occurred earlier. He also may have been predisposed to stroke genetically or have been affected by stress and high blood pressure.

There is enough evidence to suggest that actually, high intensity exercise really does help keep us healthy, but diving straight in when you're out of shape or not used to working out really isn't advised.

It's all just so confusing!

But back to these mystical four minute. If you're young, healthy and failing to fit in workouts to your busy life, these sound like a genuinely healthy backup.

[The surprising health benefits of walking]

Try our top five instant fit exercises:

- Walk up the stairs (a few times over if you're on a low floor).
- Skip - invest in a skipping rope and find a quiet corner to skip for four minutes. Smokers take a fag break, you can take a skip break.
- If you cycle or walk to work change your route to put a hill between you and the office. Or, if that's not possible, challenge yourself to power walk or cycle for four minutes along a particular stretch.
- Dance. Get up four minutes early and put on your favourite music for a few minutes before breakfast to get your heart rate up and ready for the day ahead.
- Run. You don't have to go on a five-miler in your lunch break. Just swap your heels for trainers and do a lap of the block at high speed.