The effects of EMFs on the cardiovascular system include bradycardia, decreased physiological reserve capacity, and alterations in blood pressure. Heart action may be particularly sensitive to EMF: a decrease in heart-rate was seen after 15 minutes exposure to 50 v/m, 60 Hz (z). The changes in the low-frequency studies were strikingly similar to those reported in humans who were occupationally exposed to power-frequency fields (see chapter 10).
Several studies have reported impacts of EMFs on cellular and noncellular components of blood. As we have seen previously, similar kinds of changes occurred following exposure to widely different EMFs (10, 15), and the direction of the changes differed with each animal. (11). The EMF effects on RBC and WBC were time dependent; in the case of RBC, there is evidence to indicate that animals can respond to a change in electromagnetic environment (13) as well as to the magnitude of the EMF. This is a good agreement with results described earlier showing that intermittent exposure produced different, usually greater, reactions than did continuous exposure to the same EMF.
An organism whose physiological reserve capital is being expended in a process of adaptation to an environmental agent would be expected to exhibit a reduced capacity to deal with a second simultaneous agent. This is exactly what has been seen in the immune-response studies: the fields impaired resistance to infection, decreased phagocytic activity, and altered both cellular and humoral immunocompetence.