Leisure-time physical activity increases the risk of atrial fibrillation in men
A Norwegian survey carried out between 1974 and 2003 showed that there was a graded independent increase in the risk of AF with increasing levels of physical activity in a population-based study among men with ostensibly no other heart disease. In women the data were inconclusive.
Speaking at a press conference at the ESC Congress in Paris today, Prof Knut Gjesdal from Oslo University Hospital, said that competing athletes seem to be at higher risk of developing atrial fibrillation (AF) than their sedentary mates. Less is known, however, about the training threshold above which the risk for AF increases.
Diseases or life-style factors that influence the development of AF are often present for years before AF appears. Hence the exposition for a risk factor must be recorded at baseline, and the individuals must be followed for several years. Regional large epidemiological studies on individual subjects' cardiovascular risk factors contain such information, including the subjects' self-reported leisure-time physical activity.
"Heavy exercise in leisure-time increases the risk of atrial fibrillation 2 to 3-fold in men. However, the general health benefits from physical exercise certainly outweigh the increased risk of this heart rhythm disorder," explained Prof Gjesdal.
"We had the opportunity to merge data from three population-based Norwegian surveys that used standardized methods and were undertaken during 1974 - 2003. The present analysis comprises 428 519 participants, alive and aged 30-81 years by the end of 2003. The classification of physical activity was:
1. Sedentary: Reading, watching TV, or other sedentary activity.
2. Moderate: Walking, cycling, or other forms of exercise at least 4 hours per week (including walking or cycling to the workplace, Sunday-walking, etc.)
3. Intermediate: Participation in recreational sports or heavy gardening for at least 4 hours per week.
4. Intensive: Participation in hard training or sports competitions, regularly or several times per week. »
The two major challenges were 1) to identify the subjects who later on developed AF, and 2) to exclude from the study all those who had a concomitant cardiovascular disease that could predispose to AF. Such diseases include hypertension, coronary heart disease and heart failure. The ideal group to study would be subjects with "lone AF", that is, subjects whose hearts are normal except for their AF.
Flecainide tablets are mainly used to prevent recurrencies of AF. The drug is fairly efficient and well-tolerated in patients with otherwise normal hearts, but in patients with heart disease beyond AF, serious and even lethal complications occur. Hence flecainide is prescribed only to patients with normal or near-normal hearts, and thus, flecainide users represent lone AF patients. A Norwegian Prescription Database was established in 2004. Without revealing patient identity, flecainide users and control subjects could be linked to information obtained in the health surveys, allowing researchers to compare baseline risk factors to AF.
During the follow-up period from 2004 through 2009, 1183 men and 609 women had a first-time flecainide prescription. They constitute the AF cases. The risk of AF increased with increasing levels of physical activity in men, whereas no such association was observed among women. The majority of the AF cases was 50-69 years old, non-smokers and had higher education. Resting heart rate was inversely related to the risk of having AF. The male cases had also lower levels of the major cardiovascular risk factors.
"We found a strong, statistically highly significant relationship between the level of self-reported leisure-time physical activity and AF, defined as new-onset prescription of flecainide in men. The relationship between physical activity and AF may be clearer than in previous reports since many Norwegian males are physically very active. In women, the number participating in heavy exercise was small, and the study lacks statistical power to answer whether women are running the same exercise-related risk for AF as men.
Since AF is associated with premature death, stroke and heart failure, should we conclude that strenuous leisure-time physical activity is bad for you? "This is definitely not the case. The majority of heavily exercising men have a normal heart rhythm. Our men were more fit, had slower heart rate, lower diastolic blood pressure, lower total cholesterol, they smoked less cigarettes and had more education, all factors that reduce the overall cardiovascular risk," said Prof Gjesdal.
Flecainide is a drug that does not affect physical performance. For this reason it is popular among competitive athletes, and it may be that physically active persons are overrepresented among flecainide users. Due to this concern researchers also analyzed data on sotalol users. Sotalol is an unselective beta-blocker with additional anti-arrhythmic effects. This drug is also used in non-permanent AF, even in patients with coronary heart disease. Reduced endurance capacity is a well-known side effect of sotalol, and athletes tend to avoid this drug. However, in sotalol users, a similar effect of exercise was seen: the more leisure-time physical activity at baseline, the higher was future sotalol use.
"Our selection of cases comprises only a minority of all lone AF patients. Some subjects with infrequent or mild episodes of AF are not included because they do not want long-term drug treatment. In others the AF may have progressed to a permanent, accepted state, and then there is no longer indication for flecainide," explained Prof Gjesdal.
"In conclusion, there was a graded independent increase in the risk of AF with increasing levels of physical activity in this population-based study among men with ostensibly no other heart disease. For women the data are inconclusive."
Provided by European Society of Cardiology
- Having first-degree relative with atrial fibrillation linked with increased risk Nov 14, 2010 | not rated yet | 0
- Kidney disease increases the risk of stroke in patients Mar 04, 2009 | not rated yet | 0
- Avoiding health risks could prevent more than half of all cases of atrial fibrillation Mar 28, 2011 | not rated yet | 0
- Common gene variant may increase risk for a type of cardiac arrhythmia Feb 21, 2010 | not rated yet | 0
- Study finds link between atrial fibrillation and an increased risk of death in diabetic patients Mar 12, 2009 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Dipole term in multipole expansion
3 hours ago Hi. I'm having some difficult in understanding something about the dipole term in a multipole expansion. Griffiths writes the expansion as a sum of...
Bubbles in a Pre-Boiling/Boiling pot of water
5 hours ago How is it that bubbles form on the bottom of a surface of a pot of boiling water? I think that there is probably an elementary answer to this...
Assumptions of Griffith's fracture theory
15 hours ago Any experts on Griffith's fracture theory? I am studying the subject and I am having hard time finding out if the theory is valid for all possible...
Current leading voltage or vice versa concept
17 hours ago Hello, I was wondering if there is a conceptual explanation for when current leads voltage or vice versa for capacitors or inductors with AC...
Angular Frequency of AC voltage
20 hours ago Hello, I am wondering, what is the physical interpretation of the angular frequency of AC voltage? I don't see the physicality of what the angle...
Modeling Rigid Body - Unsure about Euler angles and angular velocity
20 hours ago I'm modeling a single 3D rigid body in preparation for some more complicated modeling in order to gain a better understanding of Euler angles, the...
- More from Physics Forums - Classical Physics
More news stories
The Orsiro stent, which is a novel stent platform eluting sirolimus from a biodegradable polymer, demonstrated non-inferiority to the Xience Prime everolimus-eluting stent for the primary angiographic endpoint of in-stent ...
Cardiology 41 minutes ago | not rated yet | 0
One-year results from SOURCE XT – one of the largest, post-approval transcatheter aortic valve implantation (TAVI) registries to-date – reported today at EuroPCR 2013 show good clinical outcomes in routine clinical practice, ...
Cardiology 52 minutes ago | not rated yet | 0
A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.
Cardiology 2 hours ago | not rated yet | 0 |
(Medical Xpress)—In a recent subgroup analysis of the largest blood pressure treatment trial in history, University of Alabama at Birmingham (UAB) researchers found that women and men react the same to ...
Cardiology 10 hours ago | 5 / 5 (1) | 0
An experimental sleeping pill from US drug company Merck is effective at helping people fall and stay asleep, according to reviewers at the US Food and Drug Administration, which could soon approve the new drug.
18 minutes ago | not rated yet | 0
A paper recently published in the New England Journal of Medicine and co-written by physicians and scientists at the University of Colorado School of Medicine finds that an important genetic risk factor for pulmonary fibros ...
46 minutes ago | not rated yet | 0
Using the Department of Defense Serum Repository (DoDSR), University of Cincinnati (UC) researchers have identified a number of biomarkers for inflammatory bowel disease (IBD), which could help with earlier diagnosis and ...
47 minutes ago | not rated yet | 0
By studying the roles two proteins, thrombospondin-1 and prosaposin, play in discouraging cancer metastasis, a trans-Atlantic research team has identified a five-amino acid fragment of prosaposin that significantly reduces ...
48 minutes ago | not rated yet | 0
Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...
1 hour ago | 5 / 5 (2) | 0 |
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
6 hours ago | 4 / 5 (4) | 0 |