Half your squad gets nothing from an altitude camp

Live high and train low works on average, and the average conceals a group of athletes who come home slower than they left.

Three weeks at two thousand four hundred metres, twelve people, one budget. When they get back, the group mean haemoglobin mass is up by a few percent and the camp is declared a success. Look at the individual numbers and something less tidy is going on.

Some athletes respond strongly. Some barely move. A few come home worse. This is not a rumour, it is one of the more consistent findings in the altitude literature, and it survives all the obvious explanations.

Iron is the first thing to check and the easiest to fix. Making red cells requires iron, and an athlete arriving with low ferritin has no raw material, so the entire hypoxic stimulus produces nothing but fatigue. Any camp that does not screen and supplement in advance is wasting several thousand pounds on some of its athletes before the plane lands.

Dose is the second. The response scales with the number of hours actually spent breathing thin air, and there is a threshold below which very little happens. An athlete who trains at altitude and then drives down for dinner and stays with family in the valley has done a training camp, not an altitude camp.

The third, and the one people underestimate, is the training cost. At altitude you cannot hit the same absolute speeds. Sleep is often worse for the first week. Immune function takes a knock, appetite drops, and the athlete comes home with a slightly better oxygen carrying capacity and slightly worse neuromuscular sharpness. For a marathon runner that trade is usually worth taking. For an eight hundred runner whose event is decided by top end speed and mechanics, I am genuinely not sure it is, and I have seen enough flat autumn seasons following spring camps to be sceptical.

Which is the point. The correct question is never whether altitude works. It is whether this athlete, with this iron status, in this event, at this point in the season, gains more from the blood than she loses from the training.

Test everyone before and after, keep the numbers, and be willing to tell an athlete that the camp is not for her. Nobody does that, because the camp is also a team bonding exercise and a status symbol and a line in a funding report.

It is easier to send everybody and quote the mean.