For years, the endurance community has operated under a “more is better” philosophy, often assuming that a high level of fitness acts as a bulletproof vest against cardiovascular disease. However, a new international study suggests that for athletes aged 35 and older, the reality is more nuanced.
The research indicates that long-term, high-intensity exercise – spanning a decade or more – can actually increase the risk of specific heart conditions, most notably cardiac arrhythmias and calcification of the coronary arteries.
The Intensity Threshold
One of the researchers Thijs Eijsvogels addressed these findings in a recent interview with NOS (the Netherlands’ largest and most prominent public news outlet, ed.). He clarifies that the risk isn’t associated with casual jogging, but with “intensive sport.”
“We are talking about exercise where your heart rate and breathing rise to the point that you can no longer hold a normal conversation,” Eijsvogels explains. Crucially, this isn’t a result of a few hard months of training; the study looked at athletes who maintained this level of strain for five to ten years or more.
Finding the “Sweet Spot”
The goal of the study isn’t to discourage movement. On the contrary, exercise remains the most effective tool for lowering the risk of premature death and chronic illness. Instead, the data points toward a “U-shaped” benefit curve:
- 150 minutes per week: The baseline for moderate-intensity movement.
- 3 to 5 hours per week: The “Goldilocks” zone where athletes reach maximum health benefits.
- The Plateau: Beyond five hours, the incremental health gains diminish, and for some, the risk of heart complications begins to rise.
While scientists have yet to determine the exact “tipping point” where sport becomes “too much,” the evidence suggests that the most extreme endurance volumes may have a trade-off.
Monitoring for the Veteran Athlete
For triathletes and endurance enthusiasts over 35, the study serves as a reminder that fitness and health are not always synonymous. Experts recommend that fanatic athletes monitor for “red flags” such as a sudden drop in performance or shortness of breath during efforts that used to feel easy.
Furthermore, the research team suggests that athletes in this age bracket undergo a medical check-up every five years to monitor traditional risk factors like cholesterol, blood sugar, and blood pressure. Even if you can finish a Long Distance triathlon, these internal markers remain the most accurate predictors of heart health.