Could drinking a glass of water really stop heart palpitations?

DEAR DR. ROACH » I have a suggestion for the lady who complained of heart palpitations without any apparent underlying causes. My late uncle, when staying in our house, always requested a big glass of water by his bed in case heart palpitations awoke him. He said that drinking water stopped palpitations each time.

It also works for me and others who follow my advice. It could be a placebo effect; being convinced one can stop the palpitation by drinking water gives one a sense of control.

Not having enough fluid (what people think of as “dehydration”) is another stimulus for fast heart rates, so some additional fluid is a second reason that water may help, though not instantly.

— J.G.

ANSWER » While I try never to underestimate the power of the placebo response, there are physiological reasons that drinking water can stop palpitations. Many palpitations are coming from the top chambers of the heart — called supraventricular tachycardias — and these can sometimes be stopped by stimulating the vagus nerve. It partially controls heart rate.

One powerful stimulant to the vagus nerve is splashing cold water on the face. Drinking water is also a stimulus to the vagus nerve, and may immediately stop a run of supraventricular tachycardia.

Not having enough fluid (what people think of as “dehydration”) is another stimulus for fast heart rates, so some additional fluid is a second reason that water may help, though not instantly.

Contact Dr. Roach at ToYourGoodHealth@med. cornell.edu.