The Cardio Cocktail -Interval Training

You've probably heard of exercises being either aerobic or anaerobic...but they can be both. Blend the two together and you get a cardio cocktail that burns calories and can help push you through an exercise plateau.

Aerobic exercise is all about getting air into the body and getting the oxygen from it pumped around as efficiently as possible. Anaerobic exercise is the stuff that happens so fast, so intensely, that the body can't supply the oxygen needed and your muscles have to do without. Anaerbbic exercise is all about short sharp shocks. Intense bursts of sprinting are anaerobic, gentle jogging is aerobic. Left to our own devices in the gym most of us settle into aerobic workout after aerobic workout.

Aerobic exercise is a great fat burner. Anaerobic exercise pushes your muscles harder, though only for short periods of time not least because it produces a by­product, lactic acid, which leaves you tired and uncomfortable. One of the best ways of getting rid of lactic acid is gentle aerobic exercise - what's called active recovery - which is why cool-downs are so important. Mix aerobic and anaerobic and you have a number of benefits:

• Your normal workout becomes more challenging for your muscles promoting strength.
• You get a more intense workout out of a shorter period of time than you would do just working away steadily.
• It makes a change from a routine - whatever your preferred cardio exercise.
• It can help give you that little bit of extra push to get through a performance plateau.
• There is evidence that anaerobic exercise increases HGH (human growth hormone) levels, and HGH has anti-ageing properties.

So what do I do?

Pick a cardio machine, any machine. Now start off with a nice easy pace and if you or your chosen machine happen to be sporting a heart monitor try and keep your heart rate at a nice gentle 55-70 per cent of your maximum. After a good 10 minutes of warm-up you're ready to up the level to 70-85 per cent of your maximum heart rate. This is the optimum for developing cardio efficiency. Five minutes of that and you can go for it with an anaerobic sprint. This means taking it up to a level of effort so intense that 20 seconds is enough to wipe you out. It's up to you to define intensive, by the way. By the end of it you should feel that your performance is dropping off as your muscles simply can't keep contracting at that intensity any longer. At which point you drop back to your nice easy level for 5 minutes of active recovery which gives you time for your heart rate to drop and for your body to eliminate the lactic acid. This is the one time that the phrase 'going for the bum' has some meaning because in true anaerobic exercise the build-up of lactic acid causes that burning in your muscles. When you feel the burn it's time to slow down.