The Relationship between Stroke and Seasonal Variations in Persian Medicine

An investigation of the effects of studies on the effect of seasons and weather on the incidence of stroke indicates a contradiction in their findings.[1] Since the effect of the seasons on stroke has been recognized for centuries, and great physicians such as Rhazes (865-925 AD) and Avicenna (980‑1037 AD) have elaborated on this effect and its contributing factors. The purpose of the present study is to investigate the views of the scholars of the Persian Medicine in this regard. The sages of this doctrine believe that bodily health depends on the balance between the four humours and their unique temperament, viz.: (i) Dam (blood) as ‘hot and moist’, (ii) Safra (yellow bile) as ‘hot and dry’, (iii) Balgham (phlegm) as ‘cold and moist’, and (iv) Sauda (black bile) as ‘cold and dry’. Any factor that can disturb the quantitative and qualitative balance between the above humors causes a disease,[2] one of which is air quality. Therefore, the effects of seasonal weather changes on most diseases, including stroke, have been extensively discussed along with general recommendations to overcome the adverse effects of such seasonal changes. Cold and wet weather with less physical activity and more tendency to sleep in winter were considered to be a reason for the accumulation of waste material in the body. In early spring, gradual warming of the air mobilizes these humors and waste products, which need a way of excretion.