Ski touring, cross country skiing, cycling are all endurance sports but is doing too much of them going to kill you? I know one or two Snowheads like "beasting" themselves but are they heading for an early grave?
Below is a Norwegian article which discusses the issues wrt to Cross Country Skiing (via Google translate). Norwegian cross country skier Ole-Einar Bjørndalen was unable to train for the Olympics this year due to an afib he's acquired and has now retired from competitive sport.
-- I've got to go and lie down now after reading all this
Birken-jaget and Heart Fibrillation. Is it healthy to press the body so hard over time? | Tore Austad
Why do practitioners have higher risk of heart failure when we know physical activity is good for our heart?
In order to train in Birken, it is required that you work 3-5 sessions a week for about one year before the race. But is it healthy to press the body so hard over time? asks Tore Austad.
Long-distance skiers like Birkebeinerrennet and Vasaloppet have become more and more popular in recent years, both for the older and younger generation. Birkebeinerrennet, which is 54 km long and has an elevation of over 1000 altitude meters, is considered to be one of the toughest skiers in the world.
To train in form to Birken, it is required that you work 3-5 sessions a week for about one year before the race. Of these, at least two should be interval sessions where you work near your own heart rate. I even went to the Birkebeiner Run for the first time in 2017, and I have to admit I thought it was fun to train targeted at a competition like this.
Nevertheless, the question I have often asked myself is whether it's healthy to push the body so hard over time. To find out, I had to see what the research says.
Increased risk of heart failure
«Birkebeiner Aging Study» is a major Norwegian long-term study conducted on cross-country practitioners over 65 years who participated in the Birkebeiner Run in 2009 and 2010. 509 men aged 65 to 90 were included in the study. The main objective was to look at the relationship between long-term training and health in the elderly.
The results showed, among other things, that the fastest runners in the Birkebeiner Run had an increased risk of developing heart fibrillation compared to untrained men of the same age.
This is partly explained by the fact that 61 percent of skiers reported to be less physically active in the last year before the race than recommended. Light to moderate physical activity the last year before the run seemed to reduce the risk of heart failure. Therefore it is probably of great significance whether you have been in regular training the past year before a competition like this.
Not good with hard pressure over time
In a Swedish study, the risk of heart failure was observed in over 52,000 participants who participated in Vasaloppet from 1989 to 1998. The average age at the start of the study was 38.5. All participants completed a medical check, and participants with a previous cardiovascular disease were excluded from the study.
A higher incidence of heart fibrillation was observed in those who had completed most races and those who had faster end times. A weakness of this study was that they did not measure the participants' level of activity outside of the competition context. Probably, those with the best end times have also trained hard throughout the year, and this may explain the results.
Although this study did not control factors such as smoking, alcohol intake and food intake, it has been seen that participants in Vasaloppet generally are more physically active and are less likely to die from diseases such as cancer and cardiovascular disease compared with the normal population in Sweden.
Thus, one can not say that it is unhealthy in itself to compete in such contests, but you can see trends that last several years in a row and push your body hard over time, probably not so good.
The exercise itself is not a risk factor
A study conducted on about 17,000 healthy men in the United States suggested a dose-response relationship between hard physical activity and risk of heart failure. The risk of heart failure increased by about 50 percent in those who exercised high intensity 5-7 days a week and were under 50 years and in regular jogging. How often you jogged also seems to be directly related to the risk of developing heart flares.
Men who jogged more than 5 days per. week 53 percent increased the risk of developing heart flares compared to those who did not work out.
A major Norwegian long-term study also examined the correlation between heart flare and physical activity over a period of 14 years. 309,540 healthy people between 40-45 years were included in the study. They found that the more physically active men reported to be, the higher was the risk of getting heartburn (???). Lower resting pulse, which is a common effect seen in regular fitness training, was associated with a higher incidence of cardiac drug in both sexes.
This may seem surprising, as physical activity has proven to be among the most preventive measures against cardiovascular disease. However, it is not the training itself that is a risk factor. Physically active individuals appear to live longer than those who are not physically active. What one sees, however, is that those who participate in long-distance racing over several years appear to have a higher risk of heart failure than the normal population.
What increases the risk?
One of the reasons for the increased risk may be that the birmingham enthusiasts do not always work as structured as top athletes, despite a very high level of training.
The exercise can go a little more in jerk and nap, and you do not always have an overview of how much exercise you do each week. An excessive amount of exercise and intensity in a short period of time without sufficient rest can make you more vulnerable to overtraining and increase the risk of illness and injury.
Birken is also a very competitive event, where many people go to notice, and then it's easy to squeeze a bit too hard compared to its own form. The body probably tackles such a load best after training the body gradually over time, and did not start the drive a few weeks or months before.
Should you continue when your workout hurts?
A meta analysis of over 650 practitioners showed that practitioners had a significantly higher risk of heart failure than those who did not work out. Those who train with moderate intensity, on the other hand, appear to have less risk than unpaid. This is especially true in the elderly, which often has an increased risk of heart failure. Thus, it is likely exercise with low to moderate intensity which may be preventative for the elderly.
Why are practitioners at higher risk of heart failure when we know physical activity is good for our heart? According to Calvo and colleagues, hard fitness training over time can lead to increased fibrosis in the heart. Furthermore, this can lead to an increased risk of heart disease, through an increase in biomarkers (troponin T and I). If this is related to minor damage in the heart muscle remains to be investigated.
For hard physical training without enough rest can also lead to tissue injury, which in turn leads to inflammation in the body. An increase in inflammatory markers such as C-reactive protein (CRP) and interleukins (IL-6) is common in patients with cardiac fibrillation, which may mean that inflammation is one of the most important causes. Too much and hard fitness training can potentially create a chronic inflammatory response in exercise and exercise, which in turn can increase the risk of heart failure.
Inflammation is not dangerous as long as you get enough rest between the sessions, but you exercise too hard and too often over time, this response can turn into chronic, thus likely to have negative consequences for cardiac health.
Train the shape gradually
One study showed, among other things, that 30 percent of practitioners experienced fewer episodes of heart failure by reducing the amount of physical activity, and especially training with higher intensities. Training more with lower intensity (less than 75 percent of the pulse) is likely to cause less stress on the heart, less inflammation and thus requiring less recovery.
Surveys from athletes often show that 80 per cent of the training is performed at lower intensity, while only 20 per cent comes from higher intensity training. This is a clear argument for spending more time exercising with lower intensity ahead of the race, and gradually introducing higher intensity training (such as interval training) as it approaches competition.
It is probably not dangerous to compete with the Birkebeinerrennet as long as you have trained the form gradually. By avoiding too rapid increase in amount of exercise and intensity, you can reduce many of the disease and injury risks. Doing a greater part of your lower intensity exercise with short range of interval training is probably one of the best things you can do for your heart health.