Hello, These are nonspecific signs but may indicate some problems and in most cases is related to physical stress, sudden changes in positions from lying down to standing up, or as a result of consuming caffeine-containing beverages, tobacco, alcohol etc. In this case, they do not have any medical underlying cause, and there is nothing to be worried about. However, if this concerns you and is happening to you repeatedly then some tests should be done which include: - a complete biochemical panel - blood glucose, liver function enzymes, kidney function tests, electrolytes - a complete thyroid panel - TSH, fT3, fT4 - a complete blood count - an EKG Depending on the results of these tests, further tests and treatment may be needed. I hope I have been of help. I am happy to help, if you have follow-up questions. Wish you good health. Regards, Dr. Ivan R. Rommstein, General Surgeon