Alcohol Consumption Alters Heart Function

Ethyl alcohol, or drinking alcohol, is a toxic substance known for its ability to damage normal function in the body’s cardiovascular (heart and blood vessel) system. Specific short- and long-term problems associated with excessive alcohol consumption include high blood pressure, heartbeat irregularities called arrhythmias and a form of heart failure known as alcoholic cardiomyopathy. In a study published in March 2014 in the journal Alcoholism: Clinical & Experimental Research, researchers from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) examined the underlying changes in heart rate and heart rate variability that help explain alcohol’s damaging impact on cardiovascular function.

The heart is essential for two basic processes that keep you alive: the circulation of oxygen and other vital nutrients and the removal of carbon dioxide and other forms of waste. In order to do its job properly, the heart must pump a certain amount of blood on a regular schedule. The timing of the heartbeat (i.e., your heart rate) is maintained by specialized cells found in one area of the heart wall. The amount of blood flowing through the arteries at any given moment helps determine your blood pressure. People affected by arrhythmias experience any one of a number of unusual changes in the timing of their heartbeat; while some of these changes have only a minor impact, others can produce lethal effects. People affected by high blood pressure have too much force pressing against their arteries’ walls during or between heartbeats. People affected by cardiomyopathy have hearts too weak to deliver sufficient amounts of blood to the body.

Alcohol and Heart Function

When consumed in small amounts, alcohol can potentially have a beneficial impact on heart function. However, when it builds up in the body in any significant amount, alcohol has toxic effects that can damage a range of vital organ systems, including the cardiovascular system. People especially at-risk for alcohol-related cardiovascular problems do one of two things: participate in a pattern of short-term, intoxication-producing consumption called binge drinking or participate in heavy drinking, an activity that involves exceeding well-established daily or weekly limits for moderate alcohol intake. Either of these forms of problematic drinking can directly harm heart and blood vessel health, in addition to contributing to other problems (such as type 2 diabetes and obesity) known to place a serious burden on cardiovascular function.

Underlying Changes

In the study published in Alcoholism: Clinical & Experimental Research, the NIAAA researchers explored the changes that short-term alcohol exposure can make in both normal heart rate and the amount of heart rate variation that can occur in any given individual. During the study, they gave 12 adults intravenous infusions of alcohol large enough to produce the substance’s classic mind-altering effects. A second group of 12 adults received placebo infusions. The researchers measured the heart function in both groups of participants both before and during the infusion procedures. In addition, they asked each participant to describe any changes in his or her consciousness during the procedures.

The researchers concluded that the study participants infused with alcohol experienced a significant decline in their normal heart rates; at the same time, while under the increasing influence of intoxication, these individuals experienced an unusual amount of heart rate variability. The researchers also concluded that the participants exposed to alcohol began to experience the subjective symptoms of intoxication as their heart rates fell and grew more irregular.

The authors of the study published in Alcoholism: Clinical & Experimental Research attributed the alcohol-related changes in heart rate and heart rate variability to alcohol’s effects on an involuntary or automatic portion of the body’s nervous system. Based on their findings, they believe that alcohol’s impact on these aspects of heart function may be a reliable indicator of any given individual’s internally perceived level of drunkenness. The study’s authors also believe that their work helps explain the heart function alterations associated with short-term intoxication, as well as the longer-term changes that can lead to the onset of alcoholic cardiomyopathy or arrhythmias in people who regularly consume alcohol in excessive amounts. To reduce the risks for alcohol-related heart problems, the American Heart Association recommends that men keep their daily alcohol intake to no more than one or two standard drinks. For the same reason, the AHA also recommends that women keep their daily alcohol intake to no more than one standard drink.