Factors such as hydration, energy levels, overall muscle fatigue and temperature can have a huge impact on heart rate, so you can never really be sure if there is more to give or if you should back off to conserve your energy,” explains Sharples.
Unlike a heart-rate monitor, a power meter shows the work you’re doing right now: “This gives riders huge pacing benefits as they will know the numbers they can ride at for a set distance and stick to them. This is without doubt the most efficient way to tackle long distances.