Individuals who perceive vaping as a safer option than smoking might need to reconsider their stance. A growing body of scientific evidence is strengthening concerns that chemicals inhaled through e-cigarettes could damage the heart, blood vessels and even the developing brain, prompting renewed calls from public health experts for stricter regulation and greater public awareness.

The latest warning comes from the American Heart Association (AHA), which says research increasingly shows that e-cigarette aerosol is far from harmless. Unlike ordinary water vapour, the aerosol produced by e-cigarettes contains nicotine, flavouring chemicals, heavy metals, and other substances that the U.S. Food and Drug Administration (FDA) classifies as harmful or potentially hazardous constituents.

A recent study published in the journal Circulation: Arrhythmia and Electrophysiology found that synthetic cooling chemicals in some vaping products might disrupt the heart's electrical signals, raising the risk of arrhythmia, or an irregular heartbeat, which can lead to sudden cardiac arrest in serious cases.

"We've long known about the health threats of cigarettes and other traditional tobacco products, but as increasing numbers of e-cigarettes and other newer nicotine products are introduced into the market, we are learning more about the health threats of these products," said Dr Jason J. Rose, associate professor of medicine and chief of the Division of Pulmonary, Critical Care and Sleep Medicine at the University of Maryland School of Medicine. "A growing body of research indicates that e-cigarette users may encounter chemicals that pose a risk to their heart and blood vessels."

Researchers assert that vaping exposes users to toxic substances, such as formaldehyde and heavy metals, which have been associated with heart disease, lung disease, and various cancers. Nicotine itself remains one of the biggest concerns. Besides being highly addictive, it increases blood pressure, speeds up the heartbeat, narrows blood vessels, and forces the heart to work harder. Over time, these effects can increase the risk of heart attack, stroke, heart failure and peripheral artery disease, a condition in which narrowed arteries reduce blood flow to the limbs.

Scientists are also investigating how vaping affects blood vessels. Evidence suggests that repeated exposure can trigger oxidative stress, a process by which unstable molecules gradually damage healthy cells, and inflammation, the body's prolonged defence response, which can itself injure tissues. These changes may encourage atherosclerosis, the gradual build-up of fatty deposits inside arteries that can eventually block blood flow.

The amount of nicotine delivered by many e-cigarettes is another growing concern. According to the AHA, a single vaping device may contain as much nicotine as, or even more than, an entire pack of cigarettes. While users may briefly feel calmer or more alert, experts say these sensations largely reflect relief from nicotine withdrawal rather than genuine improvements in concentration or memory.

This finding is particularly important for adolescents. The Centers for Disease Control and Prevention (CDC) warns that nicotine exposure during the teenage years can interfere with normal brain development, affecting attention, learning, memory and impulse control while increasing the likelihood of lifelong addiction. Flavourful products, especially fruit and candy varieties, continue to attract many young users and may encourage continued nicotine use.

Recent studies published in journals, including The Lancet, JAMA, and the European Heart Journal, have similarly reported growing evidence linking long-term e-cigarette use with impaired blood vessel function, inflammation, and higher cardiovascular risk, although researchers continue to study the full extent of these effects.

"The tobacco industry relentlessly targets kids and communities with fruit-, candy-, and menthol-flavoured tobacco products that encourage use, facilitate addiction, and increase profits," said Nancy Brown, CEO of the American Heart Association. "After decades of selling products that cause disease and death, tobacco and nicotine companies cannot be trusted to protect public health. No tobacco or nicotine product can be considered safe."

As governments continue reviewing policies on e-cigarettes and other nicotine products, the AHA says proven quitting methods, including FDA-approved nicotine replacement therapy and behavioural counselling, remain the safest path for people seeking to overcome nicotine addiction rather than switching to another potentially harmful product.