A clinical trial published in ERJ Open Research in July 2026 shows that electronic cigarettes cause measurable damage to cardiovascular fitness. The study, led by Dr. Azmy Faisal at Manchester Metropolitan University, found that young vapers experience a 15% reduction in exercise capacity, matching the physiological decline observed in cigarette smokers.
These findings challenge public health strategies that have promoted e-cigarettes as a low-risk alternative to tobacco. The research demonstrates that inhaling synthetic aerosols directly impairs vascular mechanics, causing leg fatigue and shortness of breath in healthy adults under 30.
The 15% Oxygen Deficit
The study monitored 75 participants aged 18 to 30, divided into three groups: non-smokers, traditional cigarette smokers, and regular vapers with a three-year history who had never smoked tobacco. All participants had normal resting lung function and similar baseline physical activity levels.
Subjects completed an incremental cycle ergometer test to maximum exhaustion while researchers monitored their arterial function with ultrasound imaging. The results at peak exertion revealed clear physiological deficits in the vaping group:
- Oxygen Uptake: Vapers showed a 15% deficit in maximum oxygen consumption (VO2 peak) compared to the non-vaping control group.
- Carbon Dioxide Clearance: Vapers had a reduced capacity to expel metabolic carbon dioxide.
- Lactic Acid Accumulation: Both vapers and smokers accumulated lactic acid rapidly, leading to early muscle exhaustion and leg pain.
“In active, healthy young adults with normal lungs, both vapes and tobacco smoking led to worsened exercise capacity, shortness of breath, and intense leg fatigue,” Dr. Faisal stated, noting that the vascular damage from vaping is statistically identical to that of smoking.
Cellular Mechanisms of Vascular Damage
The reduction in athletic performance is driven by vascular inflammation rather than tar. Ultrasound scans from the trial showed endothelial dysfunction, a condition where the inner lining of the blood vessels cannot dilate properly.
E-cigarette aerosol contains volatile organic compounds, propylene glycol, heavy metals, and nicotine. Once in the bloodstream, these chemicals stiffen the arteries. During exercise, when muscles require more oxygenated blood, these stiffened vessels fail to expand. This forces the heart to pump against higher resistance, causing rapid breathlessness.
Global Regulatory Concerns
These physiological impacts are drawing attention from global health regulators, particularly in developing markets like Kenya. The country’s Tobacco Control Board and Ministry of Health are currently trying to regulate synthetic nicotine pouches and disposable vapes popular among youth in Nairobi.
With a June 2026 warning from the American Heart Association linking synthetic cooling chemicals to cardiac arrhythmias, health advocates warn of a potential rise in early-onset heart issues among young demographics previously considered low-risk.