Thursday, April 19, 2007

Using a heart rate monitor

The first accurate wireless heart rate monitor was invented by Polar Electro in 1977 as a training tool for the Finnish National Cross Country Ski Team. 30 years later, heart rate monitors are used by the majority of serious athletes in a wide range of sports.

A typical sports heart rate monitor consists of a chest strap containing electrodes that contact the skin and detect the tiny electrical signals produced by the heart. When a heart beat is detected a radio signal is sent out to a receiver (usually wrist-mounted) which calculates and displays the current heart rate.

If you are engaged (or plan to engage) in regular cardio-vascular exercise (running, swimming, stepper machines, rowing etc...) a heart rate monitor will help you make sure you are exercising at the optimum intensity for the goals you are seeking to achieve.

Commonly quoted heart rate zones are:

Maintain Healthy Heart: 50-60%

Weight Management: 60-70%

Increase Stamina: 70-80%

Serious athlete: 80-90%

Elite athlete: 90-100%

There are a number of ways of calculating your personal heart rate zones, the simplest one is

223 - your age

However, this can be out by as much as 15 beats per minute.

A more accurate formula is:

205.8 − (0.685 x age)

This is accurate within 6 beats per minute, which is plenty good enough to get you started (I'll outline a more accurate method in a later blog).

Cardio-vascular fitness relies on you keeping your heart beating at an elevated rate for over 20 minutes. If your heart isn't beating fast enough, you won't be getting any benefit. If it is beating too fast, your body will grind, puffing and wheezing to a halt, and if this happens too quickly, your cardio-vascular system won't benefit.

Using a heart rate monitor aids my training in a number of ways:

1. It lets me know when I'm exercising too hard. Once I see the numbers going above a certain level, I can slow down, or even stop, without being worried that I'm cheating. It has helped me not hate running, allowing me to exercise at a much lower (and yet still beneficial) level.

2. Exercise can be monotonous. Having a heart rate monitor allows you to vary the intensity of your sessions in a manageable and quantifiable manner.

3. It lets me know when I've rested for long enough. When the numbers go below a certain figure, I know I've got to up the pace.

Heart rate monitors are available from a wide range of retailers, including Amazon and Argos, from around £25 upwards. Don't buy one that doesn't employ a chest strap, they are unlikely to be accurate. The more expensive devices will have more features and functions, but won't be any better at monitoring your heart rate.

In a future blog I'll explain how you can use a heart rate monitor to measure improvements in cardio-vascular fitness.