9 Jun 2021

Irregular heartbeat in endurance exercise – is it something more?

Lisa is a 57-year-old who has been a non-elite, endurance road cyclist for many years, having always been a very fit and active child and teenager.

In the months leading up to her diagnosis, Lisa noticed episodes of irregular heartbeats, but had put it down to the intense exercise and her stress levels. One evening at home, she started experiencing shortness of breath, palpitations and light headedness and was taken to the emergency department to get checked out. Here she was diagnosed with atrial fibrillation (AF) – an irregular and often rapid heart rate that can increase your risk of strokes, heart failure and other heart-related complications.1

AF is the most common cardiac arrhythmia with increasing incidence in Australia,1 and, whilst moderate levels of exercise have been shown to be protective against developing AF, it has been found that there is a U-shaped relationship between physical activity and AF, with increasing prevalence in endurance athletes.2

Those who engage in endurance sports such as running, cycling, and skiing appear most at risk of AF. The specific mechanism that causes it is not clear as athletes who undertake other strenuous sports practices such as wrestling and weightlifting, do not have the same prevalence.2

The most compelling evidence for a dose- and intensity- dependent association between endurance exercise and AF comes from a long-distance competitive skiing event, in Sweden.In the >50,000 skiers involved in the competition, the strongest predictors of AF were the number of races they completed and race times. Further studies then went on to support these findings, confirming a five-fold increase in the risk of developing AF among older endurance athletes than non-athletes.4

To date no meaningful conclusions have been derived to show whether there is a gender-specific difference in the risk of AF in long-term endurance exercise. It is an active area of investigation.

Although intense exercise has many people feeling ‘pumped, energetic and amazing’, that feeling of invincibility should not cloud judgement of getting any irregularity of heartbeat or rate, breathlessness, dizziness, weakness, chest pain, or other unusual symptom checked out by your GP as soon as possible.

References

  1. Australian Institute of health and welfare. Atrial fibrillation in Australia. Available at:  www.aihw.gov.au/reports/heart-stroke-vascular-diseases/atrial-fibrillation-in-australia/contents/what-is-atrial-fibrillation. Accessed on: 25/05/21.
  2. Turagam MK, et al. J Atrial Fib 2015; 8(4):72-78.
  3. Andersen K, et al. Eur Heart J 2013; 34:3624-31.
  4. Abdulla J, Nielsen JR. Europace 2009; 11:1156-9.