RESUMEN
<p><b>OBJECTIVE</b>To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats.</p><p><b>METHODS</b>The study was carried out in 18 male and 18 female rats in good health conditions exposed to 50 Hz magnetic sinusoid fields at the intensity of 1000 microT, 100 microT, and 0 microT (control group) respectively, and in 18 male and 18 female rats in good health conditions exposed to 1.8 GHz electromagnetic fields at the intensity of 50 V/m, 25 V/m and 0 V/m (control group), respectively. Following haematochemical parameters for glucose, triglycerides, and total cholesterol were measured.</p><p><b>RESULTS</b>Different effects of electromagnetic fields on circadian rhythms of both male and female rats were observed. Different changes occurred in some haematochemical parameters for glucose, triglycerides, and total cholesterol (P < 0.05).</p><p><b>CONCLUSION</b>Exposure to different electromagnetic fields is responsible for the variations of some haematochemical parameters in rats.</p>