Patients having exercise limiting conditions and those at risk of developing such conditions are exposed to a regimen of hypoxic conditions that simulate various altitude conditions. The exposure is of a temporary nature, being from a few hours to most of a day or night in any one day and repeated on a personally worked out regimen of from a series of consecutive days to a regular number of “on” and “off” days, to a random number of days. An alternate regimen is such exposure for a few minutes at a time followed by normoxic rest period of a few minutes, with the cycle repeated multiple times over the course of a treatment session. The conditioning treatment strengthens the cardiac tissue and skeletal muscle and the results extend beyond the treatment periods whereby the patients condition is substantially improved.
