We are all aware of the benefits of an exercise class to an individual’s health and wellbeing. Regular cardiovascular exercise can improve the efficiency of the heart and lungs, some benefits are the lowering of the resting heart rate and increasing the strength of the heart muscles.
However are we putting our lives at risk with excessive amounts of fitness classes?
Is running or cycling for a long duration damaging your heart?
On 22nd April 2012, poor [LINK "http://www.telegraph.co.uk/sport/othersports/athletics/london-marathon/9240908/Claire-Squires-runner-who-died-during-London-marathon-buried-next-to-her-brother.html" "Claire Squires"] died whilst running the London marathon, the 30 year old woman from Leicestershire was less than a mile from the finish line when she collapsed. A tragedy that touched the hearts of a nation and donations to her JustGiving page came flooding in with over £1 million pounds raised.
Just over a week earlier on the 14th April 2012, Italian football club Livorno’s midfielder Piermario Morosini collapsed on the pitch after suffering a cardiac arrest in the 31st minute of a Serie B match against Pescara. Medical workers attempted to resuscitate the 25-year-old on the pitch. The match was abandoned as players left the pitch in tears. He died on the way to hospital.
Fabrice Muamba, collapsed on the football pitch whilst playing in the FA Cup for Bolton Wanderers against Tottenham Hotspurs. He had suffered a cardiac arrest; he was taken to hospital and is now on the road to recovery. Sadly, the only one to have a happy outcome.
One of the worst recent death tolls was in the 2005 Great North Run, where four people died. Claire Squires is the 11th person to die in the London Marathon since 1990. Cardiac arrests are frequently the cause, but hyponatraemia, brought on by drinking too much water, has also been blamed.
[B]Why did these seemingly fit people collapse?[/B]
The most common causes of sudden death in athletes are due to congenital abnormalities of the heart and blood vessels.
Conditions or defects they are born with are usually:
- Hypertrophic Cardiomyopathy (thickening of the heart muscle walls)
- Abnormal coronary arteries resulting in the reduction of blood flow to the heart.
- Heart valve abnormalities
- Abnormal heart conduction function
Sudden death in athletes over 30 years of age, is likely to be caused by a cardiac arrest, due to the blocking of the coronary arteries.
The risks are higher if you are:
- Over 50s
- Smokers
- Overweight
- Diabetics
- High blood pressure sufferers
- Those with elevated abnormal blood lipids
- or a family history of coronary heart disease
[B]Drop and give me 20........miles[/B]
It seems that heart attack risk is higher in athletes that compete in endurance events. In 1996, a study by the Journal of the American College Of Cardiology reported that 1 in 50,000 athletes partaking in fitness classes lasting over 3 hours are likely to suffer from some kind of acute cardiac trauma. The risk can last for up to 24 hours after the event. To put that in to perspective, apparently the risk is higher than a sedentary person sitting and watching TV, whilst drinking beer for the same 24 hours. I guess this is understandable as the heart is hardly under pressure from such little movement.
[B]Can an exercise class damage the heart?[/B]
Researchers from the University of Innsbruck carried out a study on 38 male participants in the 1999 Tyrolean Otztaler Radmarathon, a 230km cycling race which is considered to be just as tough as the mountain stages in the Tour de France. The athletes were experienced and well trained, with low risk and no sign of cardiovascular disease.
The researchers monitored the athlete’s blood for an enzyme called Cardiac Troponin 1. Cardiac Troponin 1 is the most sensitive and specific enzyme for the detection of heart muscle death. It is typically found in those who have had a heart attack, congestive failure or inflammation of the heart muscle.
Values were measured at the beginning of the race and at the end. Observations from the readings had reported levels had risen by 34% at the finish line!!!
And what really made me sit up and take note was that the younger athletes, who had done more training spent more time on the bike and who went the fastest had the highest values.
So, the younger and fitter athletes who went the fastest had the most damage!
Oh, what’s occurring?
The exact mechanism for the cell death is unknown, however one theory is that throughout the race the levels of adrenaline and noradrenaline (one of their functions is to regulate the heart rate) were heightened which could lead to the constriction of coronary arteries, leading to cell death in the heart.
There are a few more studies into endurance training and heart cell death which support the findings above, like the Hawaiian Ironman Triathlon where finishers Cardiac Troponin 1 levels were elevated by 9% and an alpine cross country marathon where levels were elevated in race finishers by 11%.
However, more studies need to be made for a clearer understanding of the risks. For example, do the heart cells regrow after death? Are there other factors which haven’t been considered?
Also in the studies, the heart’s function was never looked at with an electrocardiogram (ECG) so we don’t know whether there was an impairment of the heart’s function during the race. Are there short term effects? Are there long term effects? These are both questions which need to be answered.
[B]There’s no need to hit the panic button yet![/B]
There is at least one study out there which showed no elevation in Cardiac Troponin 1 in a group of runners taking part in a 100 mile Western States endurance run. Also over a year an endurance athlete will have a 40% lower risk of heart failure over a sedentary person (away from the race and 24hrs after the race).
And I’ll say again the majority of sudden death causes are down to congenital disorders which have remained undetected until the heart has been tested in a race.
Lucky for you BMF's outdoor bootcamps are only an hour long which is a mixture of aerobic and anaerobic exercise class, with regular rest periods usually being performed in the plank position!
Consider this though.........
Would a 10k give you the same benefit as a half marathon or marathon but without the risks?