Power meters measure the amount of power you are producing in order to move you and your bike forwards, in watts.

• You can determine if you are training in the right ‘zone’ for your given goal
• You know when you are improving, and when you are not
• You can pace yourself during a race very well

Training with power is more reliable than training with heart rate. This is because your heart rate is influenced by other factors, such as heat and fatigue. This could cause a problem, for example, if you were racing on a hot day – your heart rate might be much higher than normal, causing you to slow your pace for fear of going too hard at the start.

Not only that, but heart rate does not react immediately – it increases over time and drops over time. For example, when a rider sprints for 20 seconds, there will be an immediate increase in power, but this won’t show on their heart rate data.

In the same way, if you want to produce the same effort over an extended period of time (for example, a 10 mile time trial), a power meter will show you exactly how much power you are producing, whilst your heart rate will climb steadily throughout the effort.

Both methods beat training using average speed – because this is hugely affected by wind direction, strength and even air pressure.

Power meters aren’t cheap – and if they’re out of your grasp, heart rate and speed are effective – so don’t feel you can’t train well without watts – they just help.