Fit vs. AFib

Fitness is key to lowering atrial fibrillation, the importance of physical fitness at a young age, your weekly recommendations.

The Rundown

Fit vs. AFib. Atrial fibrillation or AFib is the most common heart rhythm disorder and people with the condition are five times more likely to have a stroke than those without it. According to a new paper, the key to reducing your likelihood of developing AFib is fitness.

Over 15,000 people, average age 55, who did not have AFib participated in a treadmill test between 2003 and 2012. The protocol used to assess their fitness required them to walk faster and at a steeper grade in successive three-minute stages. The rate of energy expenditure they reached was expressed in metabolic equivalents or METs. The group was divided into three fitness levels according to the METs they achieved: low (at less than 8.57 METS), medium (8.57 to 10.72) and high (over 10.72).

To put METs into perspective: One MET is the rate of energy expenditure or oxygen use, while sitting quietly. Standing or walking slowly uses less than three METs. Brisk walking uses three to six METs and jogging uses more than six.

The team followed the participants for the onset of AFib, stroke, myocardial infarction and death and analyzed the association between fitness and these conditions after adjusting for factors that could influence the relationship, including age, sex, cholesterol level, kidney function, prior stroke, hypertension and medications.

During a median of 137 months, 515 participants developed AFib. Each one MET increase on the treadmill test was associated with an 8% lower risk of AFib, 12% lower risk of stroke and 14% lower risk of MACE, which is a composite of stroke, myocardial infarction and death.

The researchers also found that the probability of not developing AFib over a five-year period was over 97% for all three fitness levels.

The abstract, Exercise performance and the risk of incidental atrial fibrillation, was presented on August 25 at the annual conference of the European Society of Cardiology. ESC Congress 2023

Start Young. A new study published in the British Journal of Sports Medicine has highlighted how physical fitness at a young age can affect health later in life. Specifically, it adds to a growing body of work that shows being in good physical shape lowers your risk of cancer.

The research followed more than one million young men in Sweden over an average of 33 years, starting when they took a military fitness test at age 18. (The test, which involved riding a stationary bike, was legally required until 2010). The scientists then looked at the rates of cancer diagnoses among the men and compared these to their fitness levels as registered on their military tests.

They found that men with higher levels of cardiorespiratory fitness in young adulthood had a lower risk of developing nine forms of cancer years later.

The men with a high fitness level had a 19% lower risk of head and neck cancer and a 20% lower risk of kidney cancer compared to the men in the low fitness level group. The risk for high fitness level participants was almost 40% lower for cancers in the esophagus, liver, bile ducts and gallbladder and about 20% lower for the stomach and the colon.

Some key limitations: The study did not include women. The participants’ lifestyle factors and subsequent fitness levels were not assessed after the initial tests, which raises questions about other mitigating factors that might have affected cancer rates.

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