For example, compared to healthy controls, cigarette smokers have cognitive deficits in auditory–verbal and visuospatial learning, visuospatial memory, cognitive efficiency, executive skills, general intelligence, and processing speed (large effect sizes, d ≥ 0.8) [29].

Nicotine can kill brain cells and stop new ones forming in the hippocampus, a brain region involved in memory, says a French team. The finding might explain the cognitive problems experienced by many heavy smokers during withdrawal, they say.

While you’re smoking: Nicotine disrupts sleep – and smoking can also raise the risk of developing sleep conditions, such as sleep apnea. But since nicotine is a stimulant, smoking can mask your exhaustion. After all, if you’re feeling sleepy, a hit of nicotine can wake you up and make you feel alert the next day.

Laxative effect This type of laxative is known as a stimulant laxative because it “stimulates” a contraction that pushes stool out. Many people feel nicotine and other common stimulants like caffeine have a similar effect on the bowels, causing an acceleration of bowel movements.

There are a couple of reasons why people gain weight when they give up cigarettes. Some have to do with the way nicotine affects your body. The nicotine in cigarettes speeds up your metabolism. Nicotine increases the amount of calories your body uses at rest by about 7% to 15%.

Some people smoke as ‘self-medication’ to ease feelings of stress. However, research has shown that smoking actually increases anxiety and tension. Nicotine creates an immediate sense of relaxation, so people smoke in the belief it reduces stress and anxiety.

Craving cigarettes, feeling sad or irritable, or trouble sleeping are some common symptoms. Some people say it feels like a mild case of the flu. For most people, the worst symptoms last a few days to a few weeks. Managing withdrawal symptoms will help you feel better and be prepared for those tougher moments.

Among adults the light or occasional smoker, that is, one who regularly smokes 5 or fewer cigarettes per day or who does not smoke every day, is in general less addicted than are daily smokers of more than 5 cigarettes per day.

As nicotine is an appetite suppressant and smokers expend more energy, weight gain due to smoking cessation is generally attributed to increased caloric intake and a slowed metabolic rate. Weight gain can be a deterrent in the smoking cessation process, even if many smokers did not smoke for weight control purposes.