Is there a regulation covering acclamation to elevation?

FM 7-22, Paragraph 4-27

The new Soldier’s threshold level of physical performance may fall below the minimum for his gaining
unit. He may be considered a borderline APFT performer or be borderline overweight. He may be fresh out of BCT, AIT, or OSUT, or may have just completed a permanent change of station move or returned from an extended deployment. These Soldiers are facing new conditions relating to physical performance (acclimatization to altitude, temperature, and humidity), which may take them up to four weeks to adapt. Although Soldiers leave IMT prepared to transition to the sustaining phase, they may de-train due to leave, transit, and in-processing at their new duty assignments just like Soldiers in operational units. New Soldiers need to train in the unit for 90 days before PRT leaders or AIs assess the Soldiers' fitness levels. This timeframe allows them to acclimatize, assimilate into a unit PRT program, and adapt physiologically and psychological