Hot and cold natures and some parameters of neuroendocrine and immune systems in traditional Iranian medicine: A preliminary study

Aim: The purpose of this study was to assess differences in persons of a Hot or Cold nature (according to traditional Iranian medicine), in terms of changes in their neuroendocrine and immune systems. Materials and methods: Thirty-seven (37) male volunteers (20-40 years old) were divided into two groups, by whether they had a Hot or Cold nature. In addition, the Warmth/Coldness ratio of all the volunteers was assessed. Plasma concentrations of epinephrine, norepinephrine and cortisol, and also the concentrations of interferon (IFN)-gamma and interleukin (IL)-4 produced by peripheral blood mononuclear cells stimulated by mitogen were measured. Results: The results showed that norepinephrine/epinephrine and norepinephrine/cortisol ratios were significantly higher, and that there was a borderline significantly increased IL-4/IFN-gamma ratio in the Hot nature group compared with those in the Cold nature group. In addition, there was a significant linear positive correlation between the norepinephrine/epinephrine and Warmth/Coldness ratios and a significant nonlinear association between the IL-4/IFN-gamma and Warmth/Coldness ratios. Conclusions: It can be deduced that the persons of a Hot nature had more sympathetic nervous system activity, less adrenal sympathetic, adrenal corticosteroid, and parasympathetic nervous system activities and more deviation of the immune system toward T-helper (Th)2 responses than the persons of a Cold nature. Moreover, the activity of the sympathetic nervous system was increased and adrenal sympathetic was decreased with an increasing Warmth/Coldness ratio. Furthermore, when the person's nature veered toward extreme Warmth or extreme Coldness, the deviation of the immune system toward Th2-like responses was greater, but this increased deviation was much more marked when veering toward extreme Warmth than toward extreme Coldness.