Hearts of Vasaloppet participants hold answers

Picture from the start of the Vasaloppet, lots of skiiers in the tracks,

The faster the race is completed, the lower the risk of high blood pressure, according to a Vasaloppet study from Uppsala University. Photo: Vasaloppet

Vasaloppet participants have strong blood vessels and are much less likely to suffer from high blood pressure. However, they may also develop athlete’s heart. Cardiologist and researcher Kasper Andersen studies Vasaloppet participants to explore the link between hard training and cardiovascular health.

Over the past decade, several articles have been published on the health of Vasaloppet participants. The studies have been enabled by a large register combining the results of Vasaloppet participants with their patient data. In total, almost 210,000 people who took part in Vasaloppet between 1989 and 2011 have been collected, alongside a control group of just under 540,000 people.

“Based on the Vasaloppet participants, we are able to define a group that is very well trained. These individuals can then be compared to the normal population, which enables us to study how performance is linked to the risk of morbidity,” explains Andersen, researcher at the Department of Medical Sciences at Uppsala University and Cardiologist at Uppsala University Hospital.

For example, Andersen has shown that Vasaloppet participants were 40 percent less likely than the general population to develop high blood pressure.

“What was interesting was that we could see that speed mattered – those who skied the fastest had the lowest risk of having the highest blood pressure. We thought it would be more evenly distributed. We therefore believe that the higher the intensity of exercise, the better it is for vascular health.”

Can lead to athlete’s heart

He also examined the risk of atrial fibrillation and stroke. He found that skiers were actually more likely than the general population to suffer from atrial fibrillation. This increased risk can be explained by the fact that those who train very intensively can suffer from what is known as ‘athlete's heart’.

“This means that the heart becomes enlarged in different ways. There may be scarring of the atrium that can lead to atrial fibrillation. Elite athletes also have a slow heart rate, which can trigger atrial fibrillation.”

Atrial fibrillation can lead to stroke, but when investigating whether the Vasaloppet skiers also had an increased risk of stroke, no difference was found compared to the normal population. Andersen says that he interprets the overall evidence on exercise and atrial fibrillation as: you should not avoid exercise just because there may be a small increased risk.

“The overall benefits of exercise are extremely positive. Those who are at the same or slightly higher risk than the general population of developing atrial fibrillation still benefit greatly from exercise in terms of protection against other cardiovascular diseases.”

Lower risk of cancer and depression

The Vasaloppet register has also been used to look at cancer risk. One study found that Vasaloppet participants had a 30-percent lower risk of developing common cancers linked to health and lifestyle. However, the skiers were only 6 percent less likely to develop all cancers.

Another study on the Vasaloppet cohort by Lund University showed that skiers were half as likely to suffer from depression compared to the general population.

None of the studies can confirm that participation in Vasaloppet specifically produces the positive effects. The training required to complete the race and the lifestyle associated with a high level of physical activity, such as less smoking and a healthier diet, are of course also important.

Andersen refers to his own findings when predicting that the picture would be similar in the case of marathon runners.

“I think the effect is the same, as long as you participate in an endurance sport. But we plan to set up a new cohort in which we include competitions like Vasaloppet, Vätternrundan, Göteborgsvarvet and Vansbrosimmet – that will give us a wider population. It will also be possible to see if there is any difference in impact between the different sports.

Another plan is to link the Vasaloppet cohort with the enrolment data. In this way, it will be possible to examine several points during the life of a Vasaloppet participant, which in turn will enable us to see how performance changes over time and how it relates to the risk of different diseases.”

Portrait Kasper Andersen

Our blood vessels thrive when they are under pressure,” says Andersen, explaining why the skiers are less likely to suffer from high blood pressure. Photo: Robert Sevcik

Bild på ben som springer. 

Andersen believes that the results would be similar if they studied athletes from another endurance sport. He wants to investigate whether this is true through a larger cohort including participants in Vasaloppet, Vätternrundan, Göteborgsvarvet and Vansbrosimmet. Photo: Getty Images

At least 150 minutes of exercise per week recommended

For those who are not interested in Vasaloppet skiing, there are other ways to improve cardiovascular health.

“It is best to exercise moderately to intensively several times a week. A total of at least 150 minutes will greatly reduce your risk of cardiovascular disease. If you want to maximise the effect, you can train up to 300 minutes a week. This is the 'sweet spot’ – more exercise than that doesn’t give any extra effect.”

Sandra Gunnarsson

Vasaloppet register

The studies referred to in the article are based on data from the Vasaloppet register. The database was set up by Ulf Hållmarker, Chief Medical Officer for Vasaloppet and Stefan James, professor at Uppsala University.

The Vasaloppet register contains data from just under 210,000 individuals who have run one of the races during the Vasaloppet week between 1989 and 2011. This group has been compared to a control group selected to be as similar as possible, for example by having the same gender and age and living in the same region.

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