Thread by @Alan_Couzens

A few brief thoughts on the implementation of #AltitudeTraining 👇

* Up to a limit, providing the right altitude is used and the athlete is healthy, IME, *everyone* is a responder.

* That said, there's large variability in response to a given altitude & elevation must, therefore, be individualized according to resting SpO2 (<95%)

* The required elevation to elicit this drop in SpO2 can change with repeated exposures & even with adaptation during long exposures, therefore it's useful to have various elevation options.

Training tolerance will vary with intensity at altitude, i.e. higher intensity sessions require lower altitudes. Another reason, it's useful to have access to a range.

Altitude exposures need to be multi-week to have a significant impact. It will generally take a week or more to just acclimate to the point that good loading can occur.

The athlete needs to be healthy & relatively fresh to adapt. Ferritin should be >30 going in and no excessively elevated markers of inflammation hs-CRP

⬆️Hydration, ⬆️CHO & Fe supplementation are generally advised.

Therefore, blood should be taken before and after *however* changes in hemoglobin (g/dl) are NOT a measure of effectiveness of the camp.

Changes in plasma volume mask *true* improvement. PV will drop quickly on exposure leading to elevated Hb & bounce back quickly on return..

...making Hb look *lower*, despite maintaining a high Hb mass. This is because the regular hemoglobin blood test is a concentration measure not an absolute mass measure. To accurately assess changes in total mass requires CO rebreathing ($$).

Without CO rebreathing, changes in power/HR are a good proxy of the short term benefit of a camp. These will typically peak out ~3-6wks post camp before returning to pre-camp levels.

/fin