Heat work is the cheap version of altitude and almost nobody funds it

A hot room and a bike will buy you plasma volume in ten days without a passport, a tent, or a camp budget.

Every federation with a middle distance squad finds money for altitude. Almost none of them find money for a hot room, which costs a fraction as much, needs no travel, and produces adaptations you can see inside a fortnight.

Here is the mechanism. Train repeatedly in the heat and the body defends its core temperature by moving more blood to the skin. To do that without losing pressure, it expands plasma volume. More plasma means more total blood, better stroke volume, and a heart doing less work at the same pace. You also start sweating earlier, sweat more, and lose less salt doing it. Core temperature at a given effort drops. Perceived effort drops with it.

The catch, and it is real, is that heat adaptations are fast in and fast out. A week or two of consistent exposure gets most of it. Two weeks away and much of it is gone. Altitude adaptations decay too, but more slowly, which is part of why they feel like a more serious investment. Serious feels like value. It usually is not.

There is a second reason heat work gets ignored, and it is cultural rather than scientific. Altitude has photographs. There is a lodge, a lake, a group of athletes looking lean at breakfast, a sponsor post. Sitting on a stationary bike in a converted store room at thirty eight degrees produces no photographs anybody wants. It is miserable, it is boring, and nobody films it.

I would still take it, particularly for anyone racing a summer championship in a hot city, because heat work does two jobs at once. It buys the plasma expansion, and it teaches the athlete what late race heat actually feels like so the first experience of it is not in a final.

Dosing is where programmes go wrong. The temptation is to make every hot session hard, which just wrecks the week. Most of the adaptation comes from time spent with an elevated core temperature, not from watts. Easy riding in the heat after a normal training session does the job and costs the schedule almost nothing.

The federations skipping this are not making a physiological judgement. They are making an aesthetic one, and it is costing their athletes free fitness.