When i get warmer my oxygen saturation drops as low as 85 - 93% and is harder to raise. why is this? (also become tired with headaches at rest)

Since I don't have: ...any clinical information , I must give general info only. O2 saturation may drop at higher body temperature b/c the metabolic rate may also increase. This can, in theory, increase the demand for O2, causing a relative mismatch between O2 supply & O2 need. Fatigue & headache are common symptoms of a low oxygen level. Symptomatic hypoxemia requires medical evaluation & monitoring. Dr. Anne.