WE LOOK AT what happens why a cyclist's heart ages, and find out what's best for your heart through the years and why for optimum health it is important to just keep on riding your bike.

There is no doubt that cycling is one of the best activities to help you develop and maintain a healthy heart, but how does a cyclist's heart change as he or she gets older and what can we do to help keep that process healthy? 

We were invited by a body with a vested interest, the John Ibbotson Fund, to a heart-screening session at the Olympic Medical Centre in Harrow to find out. 

John Ibbotson was a professional cyclist who died at the age of 27 due to a heart abnormality that showed no previous symptoms.  Cardiac screening could have detected it and when his family set up a fund to support young cyclists wanting to follow in Ibbotson's footsteps, they insisted cardiac screening e part of the process. 

Russell Clarke was Ibbotson's friend and is the driving force behind the fund - it was Clarke who arranged the screening session and he even stepped in as a subject when someone had to pull out a the last minute.  Both of the 2009 Ibbotson recruits, Tom Copeland and Dan Patten, will undergo full tests, and the support the cycling community has for the fund is underlined by the fact that pro Dan Lloyd and Roger Hammond volunteered to act as mentors for Tom and Dan. 

How they were screened  

The screening was carried out by Dr Jim Rawlins who works in the Northwick Park Hospital Olympic Medical Institute, which is also supported by Cardiac Risk in the Young (CRY), a charity who lobby for and underwrite heat screening for all young people wanting to take part in sport. 

We wanted to see how the heart changes in well trained cyclists over time, and to have a look at how at any age cycling will help to protect your heart.  One study Dr Rawlins told us about looked at left ventricular compliance, as this was know to decrease with ageing and may contribute to heart failure in the elderly.  What they found was that where compliance fell in elderly, healthy but sedentary subjects (average age 69.8 years) in comparison with a control group of young (average age 28.9 years) sedentary people, it remained the same as the young group in the masters athletes tested (average age 67.8 years). 

Leaner and Lower

The study also found that the masters athletes were leaner (17.6 per cent body fat versus 28.7 per cent in the sedentary old group and 22.5 per cent in the sedentary young), and that their heart rats and blood were lower (52 beats per minute versus 66 in the sedentary young, and 117.72 in the sedentary young. 

The teenage heart

Subject: Martin Dawkins

Age: 16

Riding history: Martin started racing two years ago and fits his bike training in around his school's physical activities. 

Miles on the clock: 10,000

Palmares: Has progressed from local racing at the Hillingdon circuit to top-10 placing in the national series and is currently competing n the track in the Revolution 'Future Stars' series. 

Current training: Around 10 hours a week.

Test result: Martin's heart is larger than the average 16 year old's, with some of the characteristic patterns, increased speed of contraction and early relaxation typical of a trained athlete's heart. 

Looking after the teenage heart: Everyone taking up a sport at this age should have their heart screened for defects.  This is the central belief of the charity CRY, and of the John Ibbotson Fund.  Once this is done a teenager should build their training slowly and avoid over-racing.  This will give the heart time to adapt to new strains and stresses and allow the athlete to develop their full potential. Plenty of rest, good nutrition and developing good training habits, like adequate warm-ups and cool-down sessions. 

There is no doubt that cardiovascular exercise like cycling helps build and maintain a strong and healthy heart in subjects of all ages, but our subjects had volunteered to help us find out how the trained heart changes over time.  To find this out, Dr Rawlins used two methods: an electrocardiogram (ECG) that records the heart's electrical activity; and what is becoming the gold standard in heart screening, an ultrasound picture of how the heart works. 

The ECG can discover problems with the electrical signals that the heart beats to, but an ultrasound in the hands of an experienced practitioner can discover a multitude of defects, especially structural ones, that could present no symptoms but could cause sudden death in anyone exercising.  And there isn't a more compelling arguments for having a test done than that. 

Getting tested:

CRY runs a programme for testing young people, details are on www.c-r-y.org.uk  Pro athletes like Dan Lloyd are tested regularly, but for the rest of us the first port of call should be your local medical practice.  You will probably have to pay but it will be worth every penny. 

The performance heart

Subject: Dan Lloyd

Age: 27

Riding history: Dan has been racing for 10 years.  He was a mountain biker at first, but after a good deal of success he changed to racing on the road.  He turned pro in 2003 and has been a member of several pro continental squads racing all over the world.  Dan is an all-rounder who can time trial, climb and race well on the flat. .  His abilities have now been recognised with a contract for the new Cervelo team, which includes the 2008 Tour de France winner Carlos Sastre.  In 2009 Dan will ridge the Giro d'Italia, his first three-week stage race. 

Miles on the clock: 160,000

Palmares: Winner of stages in the Tour of Siam and Qinghai Lake in 206.  First overall and stage winner in the Vuelta a Extremadura in 2008. 

Current training: at least 20 hours a week. 

Test results: Dan's heart is large but in proportion. 

Dr Rawlins says that proportion is important.  "A lot of screening is looking at numbers but it is very important to see if the heart looks right while its working, which is why the ultrasound scan is so good.  The chambers of Dan's heart are large, but they are large in proportion to each other.  If one chamber is out of proportion with the others that flags up a problem." 

Overall Dan's heart shows all the characteristics of an athlete's heart.  Its systolic and diastolic functions look right, and his heart's speed or contraction and relaxation is well above normal.  Dan's heart shows the characteristic fast and strong contractions of a top athlete, but it also relaxes and fills very quickly. 

Interesting though, the ultrasound scan also revealed a slight leak between the pulmonary valve, but it's nothing abnormal, so much so that Dr Rawlins would expect to see it in a cyclist of Dan's level.  "Many athletes show that leak.  It's tiny and a consequence of the heart's increased size.  the heart grows and the valves down quite shut fully.  It's definitely nothing to worry about."

Looking after the performance heart: Getting to Dan's level has taken many years of steadily increasing his training and racing volume and intensity.  He is at the point where other limiters other than the size and condition of his heart come into play, and where changes in training and nutrition are what will bring about improvement.  However, Dan still has to look after his heart with good training practices and avoiding this like training with a viral infect8ion such as the flu.  This is often difficult for career athletes, but there is proof that training with a viral infection can lead to an infection in the heart called myocarditis.  This has led to death in some, and ruined the careers of others. 

Effects of exercise

Cardiovascular exercise increases the sixe of the heart's chambers and the thickness of the muscular walls that contract to pump blood around the body.  This results in an increased volume of blood pumped with each beat, which in turn results in the heart needing to beat fewer times per minute at rest than an untrained heart.  A trained athlete will therefore have a lower pulse at rest. 

Dr Rawlins looks at many hearts in individuals from different sports and their characteristics vary.  He says: "Cyclists and rowers have the biggest, weight lifters have the most muscular but the smallest chambers."  In matters of the heart, big is best, so long as all the heart's  chambers are in proportion, so cycling would appear to be one of the best activities you can do to build and maintained a healthy heart.  But is there a characteristic of the heart that separates elite cyclists out from the rest?  Dr Rawlins says there is: "The speed at which the heart relaxes is the key, not just size or muscular development.  If the heart relaxes quickly after every beat it will fill with more blood in time for the next beat, resulting in a bigger total volume being pumped to the muscles."

What is Ultrasound?

Ultrasound is also known as echocardiogram.  The test uses high-frequency sound waves to build up an image of the heart.  A handheld device called a transducer, held to the chest, sends and receives the sound waves, which are then converted into a picture on a screen.   

The keep-fit heart

Subject: Russell Clarke

Age: 37

Riding history: A good amateur road racer in his youth who has experience of racing in France.  Russell hasn't raced seriously since 1994 but still fits in some training around his job as a police officer.  When the tests were done in mid-December, most of his training was gym based.  Russell has aspirations to race again in 2009. 

Miles on the clock: 100,000 plus

Palmares: After 43 victories at schools level, Russell progressed to be a GB international road racer and won a stage of the 1991 Beulta Cadiz

Current training: 10 to 12 hours per week. 

Test results: Russell's heart was slightly bigger and it beat slightly slower than Martin's.  Its relaxation was also more pronounced.  Overall his heart was in very good functional condition.  However, while he was checking it over Dr Rawlins kept going back to one particular area with the ultrasound equipment and asked Clarke some questions he hadn't asked the other subjects. 

What he found was that Clarke had a previously undiagnosed heart condition called Wolff-Parkinson-White syndrome.  Clarke saw Dr Rawlins after the session and he has been referred for further tests to ascertain the extend of any potential problem.  "Dr Rawlins told me had had discovered what he called an accessory pathway," says Clarke.  "This is an abnormal connection between the top and bottom chambers of my heart.  He said I've had it since birth and these pathways are generally benign, but can, under certain conditions, cause problems.  My case just shows how important these tests are because I have never had any symptoms at all." 

Looking after the keep-fit heart: Healthy eating as well as exercise is essential for anyone wanting to keep fit.  The late 30s through to the 50s are when bad eating habits can begin to make themselves felt in the form of things like high levels of bad cholesterol and high blood pressure, even in people who are relatively active.  These things also have a tendency to run in families.  All in this age group should get some basic health checks done, but those which a family history of high blood pressure must and cholesterol must be particularly vigilant.  An ECG test, and ultrasound if possible, is a good idea, and essential for anyone taking up exercise for the first time or returning to it.

The age grouper's heart

Subject: Brian Darcey

Age: 70

Riding history: Brian was an international track racer who had 36 years out of the sport before returning to it seven years ago.  During h is time out of racing he commuted to work on his bike 30 miles every day, so he never lost his basic fitness.  This fact brought him results almost straight away and he is now a national, European and world age-group champion several times over. 

Miles on the clock: Getting on for 500,000. 

Palmares: World age-group  points race and pursuit, Champion 2003 and 2004, European sprint, pursuit and points race champion 2009. 

Current training: 10 to 12 hours per week. 

Test results: Dr Rawlins says there is very limited data to compare the function of trained athletes' hearts of Brian's age.  He noted that the wall thickness, size and healthy action of Brian's heart were well preserved, but that id didn't relax as quickly as the hearts of the other subjects.  Where Dan Lloyd's relaxed at 15cm/sec, Brian's did so at 5-7cm/sec.  "As people age their maximum heart rate slows and we think that this is a safety mechanism in response to the reduction in the speed of its contraction.  If maximum heart rate was preserved the slower relaxation would mean that the heart would not fill properly between beats," says Dr Rawlins. 

Looking after the age grouper's heart: Exercise reduces blood pressure, cholesterol, maintains heart and vascular health and has a positive effect of a number of age-related illnesses, including diabetes.  One problem Dr Rawlins indicated that affects age-group athletes is a tendency over time for heart arrhythmias to develop.  "Regular checks should be made as a matter of course, but if you are riding and your heart Races suddenly increases for no real reason you should get that checked out immediately," he says. 

For the rest it is about maintaining good eating and training habits.  Concentrating on speed rather than distance in training helps maintain heart function, so does getting plenty of rest.  the main thing is keeping active, but to do that as you get older you need to pay more attention to joint and muscle health.  Injuries take longer to heal and because they do your cardiovascular system isn't getting the regular workout it needs, so preventing downtime through injury is critical. 

Getting on? Get checked out

It is not just the young and new to cycling who should get checked out.  At a certain age, and especially when you start hearing of friends who have had health problems, what is happening inside your body can play on your mind when you are hammering along on a bike. 

Getting a thorough physical check-up, including a look at your heart, as well as the practical aspect of flagging yup a potential problem can put your mind at rest and you can add some extra zest to your cycling performance. 

Knowing you have good blood pressure, blood cholesterol figures as well as a strong and healthy heart will help you commit to a training schedule, and it will help when making big efforts in competitive situations. 

How the heart works

The heart has two sides, separated by an inner wall called the Septum.  The heart is made up of four chambers and four valves and is connected to various blood vessels. 

Veins are blood vessels that carry blood from the body to the heart and arteries are vessels that carry blood away from the heart to the body. 

Heartbeat

The atria and ventricles work together by alternately contracting and relaxing to pump blood through the heart.  The heartbeat is triggered by electrical impulses that travel down a special pathway through the heart. 

The SA node (sinoatrial node), also known as the heart's natural pacemaker, is located in a small bundle of cells which are in the right atrium.  Electrical activity spreads through the wall of the atria and this causes them to contract. 

The AV node (atrioventricuarl node) is a  cluster of cells located in the centre of the heart between the atria and ventricles.  It acts like a gate that slows down the signal before entering the ventricles. 

The His-Purkinje network is a pathway of fibres that send impulses to the muscular wall of the ventricles, causing them to contract. 

Right side

Oxygen depleted blood enters the heart through two large veins, the inferior and superior vena cava and then flows into the right atrium.  It then passes through the tricuspid valve and into the right ventricle.  Blood is then pumped through the pulmonary valve and into the lungs (once the blood is in the lungs, carbon dioxide is removed so oxygen can be added to it.)

Left side

The pulmonary vein empties the now oxygen-rich blood (from the lungs) into the left atrium.  the blood then flows through the open mitral valve into the left ventricle.  The final process sees the blood being pumped through the aortic valve and into the aorta (the blood vessel that feeds all other parts of the body.)

ECG and Ultrasound testing policy

In Italy, anyone practising sport must have a yearly ECG test.  Other European cycling federations insist on the same, or at least an extensive medical examination, before granting a licence, but British Cycling doesn't do this.  This is why a BC licence is no longer a passport into some big European cyclo-sportives and you have to have a doctor's fitness certificate. 

But there is debate as to whether the ECG is really effective.  The Italians claim that testing has reduced the number of sudden deaths in sport, but their testing excludes two per cent of the applicants they screen and of that two per cent a subsequent study with more sophisticated testing showed that only 0.2 per cent had life threatening conditions, so they end up excluding a lot of people from exercise who would benefit from it. 

Sports medicine opinion says the ECG should be combined with ultrasound for a conclusive test. 

Currently Dr Rawlins says, "Only Olympic athletes at a high level will receive an ultrasound."  To underline that, Dan Lloyd was tested recently by the Cervelo Team, with an ECG only.