"I Did the Miles, My Heart Is Fine"

MASTER@HEART compared 191 lifelong endurance athletes with 191 late-onset athletes and 176 healthy non-athletic controls — all male, median age 55 — and looked directly at their coronary arteries.

The lifelong endurance athletes had more coronary plaque, not less. More calcified plaque, more non-calcified plaque, more mixed plaque, more of it in proximal segments, and more lesions causing significant narrowing.

This needs stating carefully, because it is easy to misreport. The finding is not that running causes heart disease, and it is not an argument for training less. Exercise remains one of the best-evidenced things a person can do for long-term health. What the study undermines is a specific belief: that a lifetime of high-volume aerobic training means the coronary question is already answered.

It is not answered. It is unmeasured, which is a different thing, and it is measurable.

The lipid panel is at its least informative in exactly this population, for a mechanical reason.

A routine panel reports an LDL-C figure that is usually calculated rather than measured — an estimate of cholesterol carried inside LDL particles. In a lean, well-trained person with high HDL and low triglycerides, that calculation tends to return a reassuring number. What it does not report is how many atherogenic particles are in circulation, which is the thing that interacts with the artery wall.

Two markers close most of that gap, and the March 2026 ACC/AHA dyslipidemia guideline addresses both. Apolipoprotein B counts the particles directly. Lipoprotein(a) is largely genetically determined, stays stable across a lifetime, and the guideline recommends measuring it at least once in adulthood — elevated Lp(a) is entirely compatible with elite fitness, because training does not move it.

If there is a single unexplained early cardiac event in your family and you have been reassured by your own fitness for twenty years, that combination is worth taking seriously.

Low testosterone in a lean former endurance athlete is one of the most commonly misread findings we see.

Sustained high training volume against inadequate fueling suppresses male reproductive hormones, and that suppression does not necessarily lift just because the racing stopped. A man who spent fifteen years chronically under-fueled and arrives at 49 with a low reading is not automatically a testosterone therapy candidate — he may have a fueling problem wearing a hormone problem's clothes.

Treating the second when it is the first is a real clinical error and it is not a rare one. It also means the underlying issue continues, now with a prescription on top of it. More on under-fueling that carried forward.

Bone is the third item. Impact loading builds bone durably, and non-impact endurance sports — cycling, swimming, rowing — do not deliver that loading. A cycling history is not a bone history. More on conditional bone protection.

Everyone gets the same baseline: metabolic markers, the full lipid picture, liver and kidney function, thyroid, inflammatory markers, nutrient status and hormones. What changes for an endurance history is the reading — a cardiovascular risk conversation that does not begin from the assumption of immunity, fueling addressed before hormones, and bone raised where the sport was non-impact.

What we cannot do: any imaging. No coronary calcium score, no CT angiogram, no echocardiogram, no stress test, no DEXA. If the picture warrants one — and in a strong family history with an elevated Lp(a), it may — that is a referral, and we will say so plainly rather than offering an approximation of it.