Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High prevalence of AF found among cross-country skiers

10.02.2010
Next month, in the Norwegian town of Rena, 12,000 elite cross-country skiers will line up for this year's Birkebeiner ski marathon, an annual endurance race which will take them through 54 kilometres of snow-covered countryside to the winter sports resort of Lillehammer.

The race has been run almost every year since 1932, and in 1976 almost 150 participants were invited to take part in a long-term study designed to discover the extent of latent heart disease in these elite cross-country skiers. Now, after some 30 years, the results of the follow-up study have been published and suggest that long-distance competition skiers - as well as other endurance athletes - are at an unusually high risk of atrial fibrillation, the most common abnormality of the heart's beating rhythm.(1)

Results showed that participants in the study are at a high risk of atrial fibrillation (AF) without known structural heart disease or other known causes (a condition termed "lone" AF). A prevalence of 12.8% found among the skiers who completed the study's investigations in 1976, 1981 and 2004-2006, when echocardiographic (ECG) and heart rate tests were performed at rest and at exercise. In the general population studies have found the prevalence of AF to be as low as 0.5%, with rates only rising to around 15% in men over the age of 75.

When the study began in 1976 participants were classified according to age - group I 26-33 years, group II 43-50 years, and group III 58-64 years; all had been competing in long-distance skiing events and were in the top 25% for age related performance. When the final follow-up examinations were performed during 2004-2006, a large proportion from group III (28/39) had died, leaving 78 of the original 122 available for further tests and questioning.

This analysis showed that 13 of those 78 skiers (16.7%) had experienced AF at some time during the 28-30 years of follow-up, with a current prevalence of 12.8% AF with no other known heart disease. The latter, say the investigators, "is the highest prevalence yet described in long-term endurance sport practitioners". In age group I the prevalence was found to be 18.2%. The mean age at which the AF occurred was 58 years.

The study also detected two characteristics in the skiers which may predict their risk of AF: a slow heart rate at rest (known as bradycardia) and a large left atrium of the heart.(2) Both have been suggested in previous studies as common findings in the hearts of endurance athletes. However, the study found no association between the years of training in cross-country skiing (an average of 36 years in this study) and the occurrence of AF. As a result, the authors advise that there is "still not enough evidence to recommend a specific age to reduce training volume and/or intensity". However, they do recommend that after the appearance of AF practice should be stopped or reduced "until rhythm control is attained".

Disturbances in heart rhythm, which are the most common cause of sudden cardiac death, represent one of the major cardiovascular reasons for hospital admission. Professor Josep Brugada, President of the European Heart Rhythm Association of the ESC (and Medical Director at the Hospital Clinic in Barcelona), has described their impact as "enormous", noting that around 5% of all medical expenditure in Europe is related to atrial fibrillation, the most common arrhythmic condition.

So far, only three case-control studies have found a higher prevalence of AF in athletes than in controls. However, a population-based study from 2009 showed that those with the highest level of endurance training also had the highest prevalence of AF.

Studies aiming to find an explanation for a higher AF prevalence have also found that the size of the heart muscle and chambers was larger in athletes than in controls, and this seemed a predictor for AF.

Commenting on the findings from the Birkebeiner study, principal investigator Dr Jostein Grimsmo from the Feiring Heart Clinic in Norway, agreed that enlargement of the heart's left atrium - along with bradycardia - appeared to be "an important risk factor for AF among long-term endurance cross-country skiers". This atrial enlargement, he said, is the heart's adaptation to endurance training.

"As many as 20% of young competitive athletes have been found to have an enlarged left atrium in some studies," said Dr Grimsmo. "But we are not aware of any documentation of such a high prevalence as we have found either in athletes or in controls under the age of 75!"

"But despite our findings," he added, "we still can't say why some athletes end up with AF and others don't. Genetic factors predisposing to 'athlete's heart', with enlarged cardiac dimensions and a slow heart rate, may be important as risk factors. And while it may be that prolonged endurance training over many years may not always be good for the heart, we do not yet have sufficient evidence to make specific recommendations."

Notes for editors

1. Grimsmo J, Grundvold I, Maehlum S, Arnesen H. High prevalence of atrial fibrillation in long-term endurance cross-country skiers. Echocardiographic findings and possible predictors. A 28-30 year follow-up study. European Journal of Cardiovascular Prevention and Rehabilitation 2010, 17:100? DOI: 10.1097/HJR.0b013e32833226be

2. The left atrium is one of four chambers of the heart and receives oxgenated blood from the lungs. This blood is pumped into the left ventricle, which in turn supplies this oxygen-rich blood through the aorta to the body.

The Birkebeiner ski race from Rena to Lillehammer will take place on 20th March 2010. All participants carry a back-pack weighing at least 3.5 kg.

The European Journal of Cardiovascular Prevention and Rehabilitation is a journal of the European Society of Cardiology.

Cardiac arrhythmia describes conditions in which heart beat is too fast, too slow, or irregular. The cause is abnormal electrical activity in the heart. Some arrhythmias may be life-threatening and result in sudden cardiac death. The average healthy heart beats 100,000 time per day. The most common arrhythmia (after a skipped beat) is atrial fibrillation, which mainly affects the over-65s.

More information on this press release and a PDF of the paper is available from the ESC's press office press@escardio.org

ESC Press Office | EurekAlert!
Further information:
http://www.escardio.org

More articles from Studies and Analyses:

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

nachricht Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

How gut bacteria can make us ill

18.01.2017 | Life Sciences

On track to heal leukaemia

18.01.2017 | Health and Medicine

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>