Electronic cigarettes, often called e-cigarettes or vapes, have become increasingly popular around the world. Many people believe they are a safer choice than traditional cigarettes because they do not burn tobacco.
However, scientists are continuing to discover that vaping products contain many ingredients that may affect health in unexpected ways. One group of ingredients now attracting attention is synthetic cooling agents.
These chemicals create a cold, refreshing feeling in the mouth and throat without adding a strong flavor. Because they do not fit the usual definition of flavorings, they often avoid restrictions that apply to products such as fruit or candy-flavored vapes.
A new study published in the journal Circulation: Arrhythmia and Electrophysiology suggests that these cooling ingredients may pose risks to the heart. The research was led by Dr. Alex Carll and colleagues at the University of Louisville School of Medicine in the United States.
The scientists found that synthetic cooling agents used in e-cigarettes caused abnormal heart rhythms and other changes linked to higher cardiovascular risk in mice and lab-grown human heart cells.
The cooling agents examined in the study were called WS-3 and WS-23. These ingredients have become very popular in vaping products because they reduce the harsh feeling of inhaling vapor and make vaping seem smoother and more pleasant. Sales of products containing these cooling chemicals have increased rapidly in recent years in the United States.
The researchers performed two sets of experiments. In one experiment, male mice inhaled e-cigarette aerosols containing nicotine either with or without cooling agents. The scientists closely monitored the animals’ heart rate, heart rhythm, and electrical activity during exposure.
In the second experiment, human heart cells grown in the laboratory were exposed to the cooling agents. The researchers also added a stress-related hormone to mimic some of the effects that nicotine may have inside the body.
The findings were concerning. All of the cooling ingredients affected heart rate variability, which is a measure of how the heart responds to stress and changes in the nervous system. Disturbances in this measure have been linked to a higher risk of high blood pressure and abnormal heartbeats.
The strongest effects were seen with the cooling ingredient WS-23. When this chemical was added to e-cigarettes that already contained nicotine, the number of premature heartbeats in mice increased dramatically.
The mice experienced roughly three times as many premature heartbeats as animals exposed only to nicotine and solvents. The researchers also observed signs that the heart’s electrical system was recovering either too slowly or too quickly between beats, conditions that can increase the risk of serious rhythm problems.
The human heart cells produced similar warning signs. Under normal conditions, the cooling agents did not greatly change their behavior. However, when the cells were placed under hormone-related stress, the cooling agents altered the timing of electrical activity between beats.
The researchers noted that the cooling agents did not significantly increase the amount of nicotine entering the bloodstream of the mice. This suggests that the coolants themselves may be directly affecting the heart rather than simply increasing nicotine exposure.
The study does have limitations. Mice do not respond exactly the same way as humans, and only male mice were included because previous work suggested they are more sensitive to vaping exposure.
The laboratory-grown human heart cells also cannot fully reproduce the complex interactions between the lungs, blood vessels, and heart inside the human body. In addition, commercial vaping products often contain many other ingredients that were not included in the experiments.
Even so, the findings raise important questions. The study provides the first direct evidence that synthetic cooling ingredients in e-cigarettes may negatively affect heart health. The results also suggest that people with conditions such as high blood pressure, heart disease, obesity, or diabetes may need particular attention in future studies.
Overall, this research is important because it highlights that ingredients added simply to make vaping feel smoother may carry hidden health risks. The study cannot prove that these cooling agents cause dangerous heart rhythm problems in people, and long-term human studies are still needed.
However, the findings are strong enough to justify further investigation and may encourage regulators to take a closer look at the growing use of synthetic coolants in e-cigarettes.
If you care about heart health, please read studies about top 10 foods for a healthy heart, and how to eat right for heart rhythm disorders.
For more health information, please see recent studies about how to eat your way to cleaner arteries, and salt and heart health: does less really mean more?
Source: University of Louisville.
