|MadSci Network: Medicine|
Michele- Sugar does not cause any change in heart rate. In some instances, in diabetic patients, there may be a change in heart rate, but this is due to many "reflex responses" that the body has in response to changes in blood sugar. Caffeine and other similar substances, collectively called methylxanthines which are found in tea and chocolate, certainly can cause a rise in heart rate. You or someone you know may have experienced too much coffee, with nervousness, increased heart rate and insomnia as the symptoms. Caffeine may also trigger cardiac arrhythmias such as atrial fibrillation. The name sounds terrible but a.fib means the heart's atria are not beating in rhythm with the ventricles. So caffeine, whether from coffee or colas, or other methylxanthines in tea and chocolate do affect the heart rate more than sugar.
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