Stand about 30cm away from a step, stair or bench. Make sure the step is strong enough to take your weight. The step height should be about 25 cm.

Step up and down (right foot up, left up, right down, left down) as fast as you can comfortably for three minutes. The ideal rate is 24 'full' steps per minute, and you should change your leading leg after one and a half minutes (left foot up, right up, left down, right).

After three minutes, sit down on the step, time 30 seconds then take your pulse for a full minute (see the Exercise Intensity article elsewhere in this section).

MEN - here's how your pulse reading rates:

WOMEN - here's how your pulse reading rates:

Always warm up before exercise. When stepping, place hands on hips, keep back straight and chest high. Place heel down first when stepping up, then ball of foot, don't lean forward. Always cool down after exercise. Always check with your doctor before starting any new exercise programme.

Chris Williams is an exercise physiologist and former Great Britain triathlete - check out his columns in www.Channelhealth.tv for more information.