Why are Heart Rates important for runners?

Your heart is like the engine of your body, it can idle along, accelerate quickly, and operate at a very fast speeds. As a runner, how well it does these things depends primarily on four things:

1. The condition of your body (i.e. your general health and fitness).
   
   
2. How hard you run.
   
   
3. Your running style.
   
   
4. The environment around you.

How conditioned is your body to exercise?

The job of the heart is to pump blood around the body. If your body is well-conditioned, the heart can do its job with less effort than if your body were in bad shape, and so it beats fewer times per minute and recovers more quickly to normal levels after intense exercise. This means that you can get more output for less input, i.e. you can run faster or longer.

An excellent indicator of your fitness level and the health of your heart is how quickly your heart rate recovers after exercise.

When you are most rested, your heart beats at its slowest rate. This is known as your Resting Heart Rate (RHR) and is good guide to your overall level of fitness. Generally, the lower your RHR, the fitter you are, although, as always, there are exceptions so you should only use this as a guide and should not be interpreted in isolation.

Another excellent indicator of your fitness level and the health of your heart is how quickly your heart rate recovers after exercise. When you finish exercising, your heart rate should reduce a lot during the first minute. It then enters the "resting plateau" where it reduces more slowly to normal levels, typically after around 30 minutes. The reduction in your heart rate during the first minute after exercise is known and your Heart Rate Recovery (HRR) - the higher your HRR, the fitter you are.

Your heart rate is also affected by other factors related to your general health. These include:

• caffeine
• some medications
• stress
• fatigue / over-training
• poor sleep
• poor hydratrion

You can assess your RHR and HRR using the Good Run Guide Fitness Gauge.

How hard should I run?

When you exercise or do any activity, your heart has to work harder to deliver more blood to the working muscles and therefore your heart rate rises. Your heart has a maximum speed though and this is known as your Maximum Heart Rate (MHR). This is the hardest you can train and you should only train near your MHR for a few minutes at a time.

The difference between your RHR and MHR is known as your Heart Rate Reserve. This is effectively your capacity for training and where you train within your Heart Rate Reserve is known as the Intensity Level. As any activity will increase your heart rate above its RHR you will find that your heart beat probably doesn't rise above 50% Intensity (i.e. over 50% of your Heart Rate Reserve) until you are doing some brisk walking or gentle jogging. Training for running generally starts at an Intensity Level of about 60%.

By training at different Intensity Levels, often known as Heart Rate Zones, you can condition your body in different ways depending on your goals.

As the Intensity Level increases and your heart works harder, it has differing effects on your body. At low Intensity Levels your body develops endurance and aerobic capacity. Also a high proportion of the calories burnt are fat. As the Intensity Level rises, your body burns less fat and focuses more on developing the muscles.

So, by training at different Intensity Levels, often known as Heart Rate Zones, you can condition your body in different ways depending on your goals. However, if you are unfit you should start off slowly and build up your training as you feel fitter. Whatever your fitness level, if you find your RHR is rising you may be over-training so ease back a bit.

To monitor your heart rate accurately during your training you will need a simple heart rate monitor. These are relatively inexpensive to buy and certainly help you to train within your target zones. However, a Heart Rate Monitor is not essential for the everyday runner, as you can still achieve good results by judging for yourself how hard you are running.

You can find out more about the benefits of training in different Heart Rate Zones and can calculate your own Personal Heart Rate Zones using our Heart Rate Tracker.

How does my running style affect my heart rate?

To avoid uneccesarily raising your heart rate you should try to run in a relaxed style. In particular:

• avoid tight fists or tight shoulders
• avoid shallow breathing
• on sunny days wear sunglasses to avoid squinting

How does the environment affect my heart rate?

Aside from your health and fitness, the level of effort you are putting into your runs and the style of your running, your heart rate can also be affected by some environmental factors. The following factors can cause you to run slower than normal for the same amount of effort:

• Altitudes above 1500m
• Hot weather