I have noticed that on really humid days, when the dew point is around 70 or higher, just walking around outside slowly gives me a headache after about 15 min. This is the only time that this sort of activity gives me headaches. Ordinarily, I can tolerate moderately paced walks of at least a half mile without any symptoms.

Does anyone know whether high humidity makes PCS symptoms worse, and if so, why? Has anyone else experienced this?