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 Antarctic Ice Sheet mass loss has increased
14.06.2018 | Technische Universität Dresden

nachricht WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>