I have diabetes insipidus. At night, during thrist, my heart rate jump to 140. After drinking water, it dropped to 90. My lipid profile is normal. Total cholesterol is 146,  LDL is 73,  HDL is 65,  trig 50.  CBc is normal,  white blood cells 8.5, hb 13,  palate count 411. ESR 5,  CRP 1.2 , Does dehydration also cause fast heart rate ? Day time heart rate is normal. During brisk walk its in between 105 to 110. Rest time, below 100.