Hale and hearty

Every turn of your pedal helps keep your magnificent little engine in great shape, writes Stephen Huntley.

The scientific research proves it beyond a doubt; those seemingly trite utterances found in self-help books, song lyrics and motivational calendars have been right all along; you are amazing.

Take your heart as one of many examples. It has been busily firing away every second of every day from just 22 days after your conception, and will beat over 3 billion times in your lifetime.

Your ultra-reliable motor is part of an intricate system that, among other things, ensures every one of your trillions of cells are constantly bathed in a clean and well protected environment full of fresh energy and nutrients.

Its work rate is staggering. Your complete blood supply (about 5 litres) is pumped through your body every sixty seconds through your web-like cardiovascular system that, laid end to end, stretches to 86,500km.

Given its important job description, it is unsurprising that the health of your heart is closely linked to your general health. In fact, many long-term scientific studies have shown, with amazing consistency, that resting heart rate, and how the heart recovers after exercise, are incredibly accurate predictors of mortality; and not just from heart-related conditions, but from all causes.

As scary as that might sound, it is a valuable insight, allowing you to focus on a strategy to attain and maintain robust health throughout your life; respect your heart, get it fit and strong, and keep it in great shape.

Pulsating

Your heart is a muscular pump that beats, for the average resting adult, between 60 and 80 times a minute. Each beat simultaneously pushes oxygen-depleted blood to the right side of your heart, from there to the lungs, sends oxygen-enriched blood from the lungs to the left side of your heart, and from there to the rest of the body.

Each side of your heart has two chambers – an ‘entrance’ chamber (the atrium), above, and a big, pumping chamber (the ventricle), below – connected by a valve. There is also a valve controlling the blood leaving each ventricle, making four chambers and four valves in total.

If you are lucky enough to be able to hold your ear against someone’s chest you’ll hear the heart’s hypnotic lub-dub beat that doctors also detect using a stethoscope. This is the sound of the atrium valves closing (lub) followed soon after by the closing of the ventricle valves (dub), coinciding with the heart muscle contracting (it contracts top to bottom) and pushing blood through the system.

The simplest way to measure your own heart rate is to feel the rhythmic surges of blood through an artery. You need one close to the skin surface, and probably the easiest to locate is the pulse in your wrist, the radial artery pulse.

To get a resting beat, make sure you have been seated for about five minutes, and are feeling very relaxed. Expose your wrist, palm-side up. Use the top pads of your index and middle fingers from the opposite hand to feel for the pulse (don’t use your thumb; it has its own pulse and that may confuse the reading).

Press very lightly down on the fleshy gap between the tendons that run along the middle of your wrist, and the outside of the wrist on the thumb side, just under the hand. Hold the tips of your fingers together, and parallel to the tendons.

One you’ve located the beat, you’re ready to take a reading. Set a clock with a second hand nearby, count how many times your heart beats in 30 seconds, then double that figure.

If your heart rate is below 60, don’t panic. It is most likely a sign that you are pretty fit (Miguel Indurain, the Tour de France champion, famously had a resting heart rate of 28). If you aren’t fit but have a low rate, or you have a high rate (above 80), it would be sensible to book in for a check-up with your doctor.

Fit heart

Your heart can, like other muscles, become stronger and more efficient, resulting in improved health for your entire body. And bike riding is an ideal way to get, and keep, your heart fit.

One of the standard measures of fitness is how quickly your heart rate recovers after strenuous exercise. It means taking a quick pulse reading immediately after a hard ride, then taking another reading a minute later.

Normally you would want your heart rate to drop by at least 15 beats after the first minute.  As you get fitter, you will notice it will drop by even more. Some fit riders will see a drop of 30 beats or more.

A recovery of 12 beats or less is cause for concern. Consult your doctor and get your heart tested.

If taking your pulse by the traditional method seems inconvenient, you might like to try the Instant Heart Rate app for iPhone and Android. It’s free, east to use and very accurate. You hold your finger up to the phone’s camera and it sees the change in colour of your fingertip between heartbeats. It sounds improbable but you will be surprised how well it works.

Don’t stop

Heart disease causes about a third of all Australian deaths each year. The good news is that riding just 35 kilometres a week can reduce your risk of heart disease by 50% compared to those who don’t ride at all.

So whether you wish to monitor your heart rate or not, the most important lesson is this; keep on riding!

Taking it further

You will find that measuring your heart rate immediately after exercise, and a minute later, isn’t easy. Heart rate monitors can be a boon here. They constantly measure heart rates, and using a wireless feed, display the results on a watch, or cycle computer.

You have to wear a band around your chest, which relays the findings, but the belts are well-designed, unobtrusive, and comfortable (it is not uncommon for wearers to sleep with them on so they get a heart rate reading on waking).

Not only will a heart-rate monitor aid in determining resting and recovery rates, it can also be a valuable aid during a ride, when trying to improve fitness.

Professional bike riders constantly monitor their heart rate while riding, using pre-determined zones to help gauge effort level, and pushing on or easing off according to their readings.

The generally accepted way of setting zones is to first determine maximum heart rate (the highest rate your heart can safely reach). A medically supervised cardiac stress test can accurately determine this maximum rate, but a variety of rule-of-thumb formulas are also commonly used.

Subtracting your age from 220 was the standard formula, but its reliability has been questioned. A 2007 study found 206.9– (0.67 x age) was more accurate, while a 2010 study concluded 206 – (0.88 x age) was the best for women. Note that all formulas are based on averages only, and don’t take into account individual fitness or health.

Training zones are worked out based on a percentage of maximum heart rate. Once again, there are a variety of suggested zones, but typically 50%-60% is set as a comfort zone, 60%-70% is good for fat burning and building endurance, 70%-80% is aerobic and good for high-end endurance, 80%-90% is anaerobic and builds intense effort fitness, and 90%-100% (the red zone) is an area you can go to briefly for absolute maximum effort.