By Harshit
BALTIMORE, USA | NOVEMBER 22, 2025 | 09:30 AM EST
Smoking even a few cigarettes a day may be far more dangerous than many realize, according to a large new review that examined nearly two dozen long-term studies. The research, published November 18 in PLOS Medicine, concludes that “light” smoking — as little as two to five cigarettes daily — sharply increases the risk of heart failure, stroke, and early death. Researchers found the danger persists for decades, even after quitting.
The findings underscore a critical public health message: no level of smoking is safe, and complete cessation at an early age remains the most effective way to lower long-term cardiovascular harm.
A Deep Look at Long-Term Damage
The research team, led by Dr. Michael Blaha of the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease, analyzed data from over 300,000 adults across 22 longitudinal studies. Participants were followed for up to 19.9 years, providing one of the most comprehensive looks yet at how low-intensity smoking affects long-term heart health.
Across all studies, the population experienced:
- 125,000+ deaths
- 54,000 cardiovascular events, including heart attacks, heart failure, and strokes
When the researchers compared smoking habits, they found that people who smoked just 2–5 cigarettes per day had:
- 60% higher risk of death from any cause compared with never-smokers
- 50% higher risk of heart failure
- Significant increases in other cardiovascular complications
Crucially, many low-intensity smokers believed their limited use protected them from major health damage. The data shows the opposite.
“These results reaffirm that smoking harms the cardiovascular system even at very low doses,” the authors wrote. “Light smoking is not a safe alternative.”
Risks Drop After Quitting — But Don’t Disappear Quickly
The study also examined long-term outcomes for former smokers. It found the biggest risk reduction occurs within the first 10 years after quitting, with continued improvement over time.
However, even after decades without smoking, former smokers still showed higher cardiovascular risk than lifelong non-smokers.
People who quit entirely at younger ages — especially before age 35 — saw the strongest protective benefit, highlighting the importance of early cessation.
Cutting Back Is Not Enough, Experts Warn
One of the most important takeaways is that reducing the number of cigarettes smoked per day does not significantly lower cardiovascular risk.
Light smokers were still far more likely to face heart complications than never-smokers — a finding that supports long-standing public health campaigns emphasizing full cessation rather than partial reduction.
“These findings show that even small amounts of smoking cause substantial harm,” Dr. Blaha said. “The amount of time since complete cessation is more important than how many cigarettes someone smokes per day.”
Why Few Cigarettes Still Cause Major Damage
Cardiologists note that cigarette smoke contains thousands of chemicals that rapidly damage blood vessels, stiffen arteries, promote clot formation, and trigger inflammation — processes that can occur even with minimal exposure.
Even occasional cigarettes:
- Impair endothelial function (the lining of blood vessels)
- Increase plaque buildup
- Raise blood pressure and heart rate
- Reduce oxygen flow
- Accelerate atherosclerosis
This means a “light smoker” can accumulate major cardiovascular damage over the years even without heavy daily use.
Public Health Implications
The study arrives at a time when patterns of tobacco use are changing. Many Americans no longer smoke a pack per day, but millions still engage in occasional or low-intensity smoking — sometimes believing it reduces long-term harm.
Public health experts say this study should dispel that misconception.
The authors emphasize that early, complete cessation remains the most effective path for lowering long-term heart disease risk. Prevention efforts must continue focusing on young adults, who are most likely to start or maintain low-intensity smoking.
“This is one of the largest and most rigorous analyses of cigarette smoking and cardiovascular disease to date,” the authors wrote. “Even low doses confer large risks. It is imperative to quit as early in life as possible.”