gh SWALLOWING ACCELERATES THE HEARTBEAT

Human life depends on the cardiac activity, therefore researchers have been studying for centuries all factors that can affect it. Among other things, researchers have been interested in the heartbeat frequency regulation. The purpose of such investigation requires that the heart systematically broke the established rate, which is harmful for health. However, the researchers have now opportunities to frequently influence the neural regulation of cardiac activity with no damage to the person under investigation. There is no need to frighten or exhaust anybody with physical exercises. According to the researchers of the Laboratory of Cardiovascular System Regulation, Russian Cardiological Research-and-Production Complex, Ministry of Health of the Russian Federation, a good gulp makes healthy people experience brief palpitation.

Twenty years ago scientists knew that swallowing was accompanied by brief but significant acceleration of heartbeat, but they could closely investigate the phenomenon only after electrocardiogram was invented. It has turned out that when swallowing, the heart of healthy people beats at the frequency exceeding 90 beats per minute, but it is not clear why that happens. Is that a reflex phenomena, i.e. response to stimulation of respective receptors in the gullet, or fulfillment of the central nervous system's command? In general, it is interesting to understand what makes our hearts tremble when we are eating a sandwich.

Moscow cardiologists have investigated alterations of cardiac rate when a person is swallowing. The research involved 23 healthy volunteers of different age. In the morning, electrocardiograms were recorded in the chest leads of the volunteers who had not eaten or smoked. Simultaneously, swallowing acts were recorded by the electric manometer fastened on the neck. Ten minutes later, the same recording was repeated in the lying position. The persons under research were asked to make one gulp (for 5-6 times) every 30 seconds, then to make 3 gulps successively (4 attempts with a one-minute pause) and 5 gulps. The research findings have been processed by specially developed software.

After a gulp is made, a healthy person experiences quick heartbeat acceleration, but the reaction last for 10 second at most. If the first gulp is followed by others, the heartbeat frequency continues to grow, but at a much slower rate. The "peak" occurs after 5-10 gulps are made and largely depends on the swallowing frequency the person is capable of. Nature would not allow its children to swallow the way through to a heart attack. It is also important to take into account the position taken by the individual. If a swallowing person is lying, the heart makes about 13 additional heartbeats per minute, if the person is standing - 8-9 (remember, physicians insist that it is harmful to eat in a lying position). Once the person stops swallowing, the palpitation calms down.

Having comprehensively considered the swallowing act, the researchers determined what neurons impact the cardiac rate and at what stage of swallowing this happens. Therefore, from the cardiologists' point of view, harmless swallowing can serve a convenient physiological trial for investigation of cardiac rate regulation. However, the status of the system regulating cardiac activity cannot be evaluated only by the heartbeat frequency alteration. The gullet's sensitivity is of significant importance as well: two persons under experiment were required to swallow after the 10% Lydocaine was sprayed into the gullet. As a result, one of the persons failed to swallow at the command, but spraying did not have any affect on the other person.

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