How many cigarettes do you think you'd have to smoke per week to label yourself a 'smoker'? 30? 40? 50? 100?

The truth is, there's no real definition. But what is clear is that the idea of 'social smoking' - having the occasional cigarette when you're out with a certain group of people, or when you're having a drink - is often used by people as a way of justifying their occasional habit.

"I'm not an actual smoker, I just socially smoke"

But how much damage can intermittent smoking actually do to your body? "Social smoking is a misnomer," says Dr Richard Russell, Consultant Respiratory Physician and medical advisor to the British Lung Foundation. "Whether you smoke socially or not is not the point. It's the toxic chemicals you are inhaling. Even occasional smoking puts your health at risk – the only safe level of smoking is nothing at all."

Ah - now there's a stern warning if ever you heard one. But the doctor points to research to back his concerns up. "Researchers from the University of Bristol estimated that over a lifetime each cigarette could take 11 minutes off your life," he notes. "A long-term study found that people who smoked 1-4 cigarettes a day have a significantly higher risk of dying from all causes than a non-smoker," he adds.

Your general health
The reason being, when you smoke, you become more susceptible to lung infections. "Even light smokers have an increased risk of developing lung infections, and when they have infections the symptoms will often last longer than non-smokers. This because your lungs will get worse at clearing debris," Dr Russell says.

It can also impact your ability to breathe. "Cigarette smoke damages the linings and walls of the lung tissue, which leads to the walls breaking down to form larger air spaces than normal. This results in a lower surface area for oxygen to transfer into the blood. This leads to breathlessness especially when exercising," he explains.
The way you look
If it's vanity that'll convince you not to have a fag next time you're at the pub, then you might want to know how even the occasional cigarette can impact your appearance. "When you smoke a cigarette, you inhale over 5,000 chemicals including tar and nicotine. The toxins in your body can cause cellulite," advises Dr Russell.

And it's not ideal for your skin, either. "Smoking reduces the amount of oxygen that gets to your skin. This means that if you smoke, your skin ages more quickly and looks grey and dull," he notes. "Smoking prematurely ages your skin by between 10 and 20 years, and makes it three times more likely you'll get facial wrinkling, particularly around the eyes and mouth."

But there is one positive: "Once you stop smoking, you will prevent further deterioration in your skin caused by smoking and improvements in the complexion occur," says the doctor.

Long-term
It's fair enough to assume that if you only smoke a handful of cigarettes each month, you're exempt from any of the fears a full-time smoker might have about developing cancer in the long-term. But according to the expert, this isn't necessarily the case.

"It has been recently discovered that there are significant effects on the DNA in many cells throughout the body from even a low level of smoking," he says. "Researchers at the Wellcome Trust's Sanger Institute analysed the DNA of more than 5,000 cancers to see how tobacco smoke mutates our DNA. They found that just smoking four to five packs of cigarettes in a lifetime causes several permanent mutations in many cells throughout the body and thus increases the risk of cancer."

So although it might feel harmless having the odd cigarette when you're out with your friends, it seems it's more problematic than you ever really thought.