While the popular belief is that smoking largely affects the lungs because they get directly exposed to inhaled smoke, health experts warn that it also impacts the entire cardiovascular system.
According to the World Health Organisation (WHO), smoking tobacco is globally the second leading cause of heart diseases after high blood pressure. Nearly 12 per cent of cardiovascular deaths worldwide occur due to tobacco abuse and secondhand smoking.
In tobacco cigarette, there is combustion, a burning of an organic material that generates temperatures up to 900 degree Celsius. Chronic exposure to this tends to thicken blood vessels, making them weaker in the long run. This can lead to blood clots and ultimately result in stroke or peripheral heart diseases.
"Inhaling the smoke from tobacco builds fatty material -- atheroma -- in the heart of the smoker which then damages the inner lining of arteries and also narrows them further," Tapan Ghose, Director & HOD, Cardiology at Fortis Flt. Lt. Rajan Dhall Hospital, told IANS.
"This narrowing can cause the angina, stroke or heart attack," he added.
Further, the presence of nicotine in the cigarettes raises the blood pressure, which can have a detrimental effect on the heart's oxygen balance.
"Nicotine causes thickening of the blood vessels, which hampers the blood flow and also causes high blood pressure or hypertension," Mukesh Goel, Senior Consultant, Cardio Thoracic & Vascular Surgery at Indraprastha Apollo Hospitals, told IANS.
Tobacco also has carbon monoxide, which blends with haemoglobin in the blood more easily than oxygen does, thus affecting the oxygen supply in the body.
The carbon monoxide prevents the blood system from effectively carrying oxygen around the body, specifically to vital organs such as the heart and brain, the experts said, adding that apart from regular smokers, those who inhale the smoke passively may also be at risk.
WHO states that of the seven million lives that tobacco claims worldwide each year, almost 900,000 are passive-smokers.
Tobacco, whether smoked, swallowed, or chewed poses multiple hazards. In addition to affecting the lungs and heart, it also increases the risk of head and neck, lung, esophageal, pancreatic, and urologic cancers.
According to a recent study published in The Journal of Physiology, smoking could directly damage the muscles by reducing the number of blood vessels in leg muscles, which in turn reduce the amount of oxygen and nutrients the muscles receive.
This may impact the metabolism and activity levels.
Moreover, smoking also affects both male and female fertility, doctors said.
"Women smoking tobacco reduce their chances of conceiving by at least 60 per cent and is also linked to ectopic pregnancy and other tubal factor infertility," Sagarika Aggarwal, an IVF expert at Indira IVF Hospital, New Delhi, told IANS.
On the other hand, male smokers can suffer from decreased sperm quality with lower mobility and increased numbers of abnormally-shaped sperms.
Moreover, chain smoking might also decrease the sperm's ability to fertilise eggs.
Besides causing infertility, tobacco during pregnancy can also lead to multiple issues ranging from miscarriage to under-development of the foetus and making the child susceptible to various forms of disorder such as Attention Deficit Hyperactivity Disorder (ADHD), Goel noted.
Quitting is the best way, the experts said while discouraging the use of alternatives like e-cigarettes.
"While it is true that e-cigarettes have less quantity of tobacco as compared to regular cigarettes, bidis or hookah, but they also expose lungs, heart and other organs to very high levels of toxic substances," Goel said.
Other measures like clinical interventions, counselling and behavioural therapies can help people quit tobacco abuse.
"Nicotine replacement therapy, including nicotine patches, gum, lozenges, inhalers etc, has been found to be effective. Combination therapy with drugs like bupropion has been found to be more effective than nicotine replacement alone," said Viveka Kumar, Senior Director, Max Heart & Vascular Institute, Saket.
Kumar also emphasised on the role of mass media in spreading awareness about the harmful effects of tobacco, while curbing the easy access to tobacco, especially among the younger vulnerable population.
"Availability and accessibility of smoking cessation programmes to smokers who want to stop smoking remains an area which needs to be addressed," Kumar said.