It is well known that during intense training and competitions athletes show a remarkable reduction of their immunological responses. As a matter of fact, during these periods athletes very frequently (five to ten times more than average) fall ill. In order to correct this situation, in the USSR immunomodulator drugs are used together with high frequency electromagnetic waves which are applied on the body surface corresponding to the adrenal glands. In this way body desensitisation is accelerated. One hundred high-level athletes received an application of electromagnetic waves on the body surface corresponding to the thyroid gland and thymus, so as to lower glucocorticoid activity and activate lymphoid tissue. Indices of immunologic reactivity and hormonal levels after electromagnetic treatment were measured in all athletes.