The hidden costs of excessive exercise: When fitness becomes a fixation
Blog for Life is a series of opinion pieces from the team at CPC RPA Health for Life Program, our clinical, research, culinary and education experts developing resources for healthy longevity. Kate Hutchinson, exercise physiologist, explores how exercise can become an unhealthy fixation.
‘Exercise is medicine, but like any medicine, the dose matters’: two major studies have revealed a confronting truth: pushing exercise to the extreme can backfire. From disrupted heart rhythms to liver damage, the risks of overtraining may persist long after retirement from elite sport. For lifelong health, it’s time to reconsider how much is too much.
Pushing limits comes at a cost
A study by Flannery et al, which was published in the European Heart Journal, found that former Olympic-level rowers were 6.8 times more likely to develop atrial fibrillation (AF) or irregular heartbeat than non-athletes. Even without typical risk factors, these athletes also faced higher stroke rates, suggesting that long-term, high-intensity endurance training may increase health risks, not reduce them.
The heart remembers
Decades after retiring, these athletes still showed enlarged atria, slower heart rates, and disrupted electrical conduction. These structural changes, remnants of years of intense training, point to long-term cardiac remodelling that isn’t always harmless or reversible.
Genes add fuel to the fire
Athletes with high genetic risk for AF were four times more likely to develop arrhythmias. The takeaway? Genes and training load are both powerful forces. When combined, they significantly raise the chance of developing long-term heart issues even in the fittest bodies.
The liver takes a hit, too
A study by Liu et al, in Cell Metabolism, showed that overtraining can damage the liver. Too much exercise leads to excess lactate buildup, triggering the formation of “lactate bodies”, tiny vesicles that promote liver scarring (fibrosis) and cell death, through a little-known protein called SORBS3.
Overtraining hits more than muscles
The new mechanism shows that exercise-induced metabolic overload doesn’t just wear down muscles; it can impair vital organs like the liver. While liver damage is usually linked to alcohol or obesity, this study links it to overtraining for the first time.
The myth of ‘more is better
This evidence challenges the long-held belief that more training equals more health. While moderate activity improves lifespan and resilience, extreme endurance, especially over the years, can tip the balance from benefit to harm, particularly in genetically susceptible individuals.
Extreme sport, unseen stress
High-performance fitness has become aspirational. But weekend warriors and amateur triathletes often mimic elite routines without the recovery, monitoring, or genetic screening. The risks are rarely discussed. Health professionals may need to rethink how we guide people training at the edge.
The power of a personalised approach
At the Charles Perkins Centre, we support research that recognises no two bodies or life stages are the same. What's right for one person may be risky for another. That’s why a personalised approach to exercise matters. Seeing an ESSA-accredited exercise physiologist can help tailor movement plans that support your unique health needs, whether you're managing chronic conditions, recovering from injury, or training for long-term performance.
What’s next?
Should athletes be screened for AF risk? Can training plans evolve to support both performance and long-term health? These studies open new directions for research, policy, and coaching, reshaping how we define “fit” in the age of personalised medicine.
Train for life, not just the finish line
Exercise is essential, but more isn’t always better. Movement should energise, not erode. With balance, recovery, and tailored plans, we can embrace physical activity not just for medals or marathons, but for health, happiness and longevity. More isn’t always better.