A heart rate monitor is a useful tool for longer distance runners. This is particularly true if you can map it against your performance or have had VO2 or Lactate Threshold testing done.

It is often of use as well as a measure of when you are not quite right and it might be a good idea to call it a day on a session. Many athletes will take their pulse first thing in the morning (obviously this doesn't need a monitor!) as an elevated pulse is a sign that you may be suffering from an infection and resting would be better.

So - what should you look for in a heart rate monitor?

As well as reading current heart rate, it is useful to know maximum and average heart rates in the course of a piece of exercise.

Will it tell you the time at which your pulse was at a certain reading?

Can it give you an alarm if you pulse is in a particular zone? If so, will it give reading for the amount of time in this zone?

Can you track your speed of recovery after sessions?

Does it have a GPS built in to give speed and distance as well, maybe an altimeter as well?

Can you download the information to a PC?

Clearly, there is plenty to think about here and as with other gadgets the more components you want to more it will cost. As a rough guide the very cheapest monitors start at about £30 and go up to about £300.