Heart rhythm is controlled by the sinoatrial node and the atrioventricular node, which reside in the heart. These send out electrical impulses that cause the heart to contract at about 60 to 80 beats per minute. A heart palpitation is an abnormal heart beat that makes you aware of the beating. It can be brought about by overexertion, for example, during intense exercise, or as a result of an impulse that triggers the release of adrenaline, for example, getting a fright. Ingested substances, such as drugs, alcohol, nicotine and some nutritional supplements, can also cause heart palpitations. Always consult a doctor before starting a supplement of any kind.
Vitamin D is synthesized in the skin upon exposure to sunlight; it can also be obtained from foods such as oily fish and eggs, and from supplements. It is essential for proper calcium metabolism and for a healthy immune system, among other functions. However, a vitamin D overdose can cause heart palpitations, according to a March 2011 report from the University of Utah regarding a vitamin solution that contained toxic levels of vitamin D as well as A. Other symptoms of vitamin D toxicity include fatigue, headaches, nausea and altered mental status. You do not need to worry about getting too much vitamin D from the sun, however; the "Manual of Dietetic Practice" reports that it is not possible to get too much vitamin D this way.
Caffeine is generally obtained from the beans of the coffee plant, but it's also found in tea and can be obtained in caffeine supplements. Caffeine is also present in supplements containing guarana and in most energy drinks. Caffeine acts as a stimulant, delaying fatigue and improving mental alertness. However, too much caffeine can cause heart palpitations, reports the Harvard Medical School. According to the American Heart Association, though, up to two cups of coffee a day is not harmful.
Yohimbe is a nutritional supplement obtained from the yohimbe plant. It is used as an aphrodisiac and as a weight-loss aid; but scientific evidence of its efficacy is conflicting. Yohimbe is associated with a number of side effects including heart palpitations as well as headaches, nausea and anxiety, according to the NIH National Center for Complementary and Alternative Medicine.
Ephedrine is an herbal extract obtained from plants of the Ephedra family. It is very popular in Chinese medicine and has been used in nutritional supplements as a stimulant and for weight loss. In 2004, the U.S. FDA banned the use of ephedrine in nutritional supplements; however, the ban does not apply to Chinese herbal medicine, and ephedrine can still be found in these products. Heart palpitations are among the extract's side effects, as are high blood pressure, kidney stones, tremors, heart attack and possibly death, according to the National Center for Complementary and Alternative Medications.