The effects of smoking - a reminder

Brain

Mood

• Nicotine is a centrally acting drug. In low doses it acts as a brain stimulant causing a feeling of being high.
• In higher doses, it acts as a brain depressant, producing feelings of calmness (anxiolysis).

Addiction

• Nicotine is also highly addictive, causing changes in the numbers of naturally occurring nicotine receptors in the brain. A sudden reduction of a regular smoking habit induces a withdrawal reaction, with craving associated with agitation and restlessness.

Appetite and Taste

• Nicotine is a direct appetite suppressant in the brain. This may explain why in general, smokers are slimmer than their non-smoking counterparts.
• Nicotine also alters taste function in the tongue. This may explain why smokers often complain that food tastes bland, and why they add more salt to their food so that they can taste it (which in turn raises blood pressure - see 'heart'.

Psychology

• Most social smokers use nicotine as a recreational drug, where it is used together with alcohol to enhance feelings of well being and elation.
• Most regular smokers would admit to using the drug as a means of calming their nerves, such that they begin to feel more jittery and anxious when nicotine levels are low, making them desperate for their next 'fix'.
• It may be that regular smokers in general have more problems with anxiety, and use nicotine as a treatment for it. Recognising this psychological need is important before embarking on a programmed withdrawal.

Heart

• Nicotine stimulates the cardiovascular centres in the brain stem causing a sustained rise in heart rate and blood pressure. It also acts on the peripheral circulation causing an increase in the peripheral vascular resistance (how hard it is to pump the blood around the system).
• These three factors cause an increase in the work done by the left ventricle (main heart pump. The increase in work also increases the amount of oxygen consumed by the left ventricle.
• In established coronary heart disease (narrowing of the heart's arteries), the coronary arteries are not able to supply enough oxygen to the left ventricle during periods of exercise causing angina symptoms (acute hart cramp caused by shortage of oxygen).
• Smoking places an extra load on the heart because of its effects of increasing blood pressure, heart rate, left ventricular work and oxygen consumption. Therefore, those with established angina can see a vast improvement in their exercise tolerance by stopping smoking as this extra load is removed. In some cases, reduction in angina medication is possible.
• Stopping smoking can also reduce the need for hypertension treatment, allowing the peripheral vascular resistance to fall back to normal. Reduced salt intake, because you can begin to taste your food again, also contributes to the drop in blood pressure.
• The longer the smoking habit, the longer it takes for the cardiovascular risk to diminish. Doctors do not yet know when the effects have become irreversible.

Lungs

Carbon Monoxide

• Non-smoking city dwellers have about 2.5% carbon monoxide in their blood streams. This comes from carbon monoxide pollution in the air we breathe (other smokers and car exhausts).
• Regular smokers can have up to 15% carbon monoxide in the blood streams, the source coming from the slow inefficient burning of tobacco.
• Oxygen is normally carried in the blood stream by a molecule called haemoglobin. Each haemoglobin molecule, when fully saturated at 100%, carries 4 oxygen molecules giving blood its red colour. Carbon monoxide binds to haemoglobin in the blood stream displacing the oxygen it normally carries. So, instead of normally having 100% of the haemoglobin saturated with oxygen, smokers are down to about 85% of normal. This is like living half way up Mount Everest.
• This means that there is also 15% reduction in the supply of oxygen to the peripheral (distant) tissues, such as the fingers and toes.
• An interesting fact is that machines designed to measure oxygen saturation (pulse oximeters) cannot pick up carboxyhaemoglobin (what you get when you mix carbon monoxide with haemoglobin), and therefore they over-estimate your oxygen saturation. For example, the machine will tell you that you are 97% saturated with oxygen, when you're really sitting at 85%.
• The only way to tell what your real oxygen level is, is to have an arterial sample testing using a Co-oximeter, and these aren't generally available except in intensive care units.

Particle Removal

• In the trachea (main wind pipe) there is a system of fine hairs (cilia) which continuously beat rhythmically removing dust, and other inhaled particles, from lungs. These particles are lifted upwards to the top of the trachea, where they are then swallowed into the stomach
• Smoking causes a decrease in the cilia length, making them short and stubby, beating less efficiently, causing a build-up of dust and other particles in the lungs
• The Type II alveolar cells normally move around in the tiny air sacs in the lungs (alveoli) devouring and removing dust particles like a vacuum cleaner.
• Smoking causes a reduction in the numbers and speed of movement of these type II alveolar cells - just like using the vacuum with the bag full - very inefficient.
• The reason why smokers develop a chronic cough is that the accumulation of debris causes irritation of the lining of the trachea and bronchi (smaller lung tubes), s the normal mechanism for removal has failed. Regular smokers find that they need the first cigarette of the day to make them cough enough to remove the sputum that has accumulated overnight. The smoke irritates the lining of the trachea, making them expectorate
• The main source of dust in smokers lungs is carbon soot particles from the burning of tobacco. Smokers lungs are blacker than normal because of the slow build-up of soot over time.
• As the soot is released during smoking, it absorbs various toxins released in the tobacco smoke. When the soot particles reach the inside of the lungs, the toxins slowly leach out over a period of time, increasing the risk of cancer formation.

Chronic Infection

• Inefficient particle removal in the trachea and in the alveolar cells markedly increases the risk of chronic bronchitis. Chronic Bronchitis is defined as cough and sputum production each day for more than 3 months in the year.
• Chronic infection and intermittent more serious infections lead to progressive lung destruction. The normal architecture of the lungs is destroyed (emphysema), making the lungs less efficient at transferring oxygen to the blood stream.
• This leads to breathlessness, poor exercise tolerance, and the need for the continuous use of oxygen by mask.

Circulation

• Chronic lack of oxygen in the circulation (85% -v- 100%) stimulates the production of more red blood cells by the bone marrow, by way of compensating for the reduced oxygen delivery. The normal haemoglobin content of the blood is between 12 and 14 g/di. Smokers often have levels as high as 17 g/di.
• An increase in haemoglobin content increased the stickiness or viscosity of the blood as it flows around the body. Not only does this make the blood harder to pump around (another strain on the heart), but it also makes the blood more likely to clot.
• The effect contributes to the increase in heart attacks and strokes seen in smokers, which are due to occlusion of small diseased blood vessels by thrombus (thrombosis = clot formation in the presence of arteriosclerosis).
• Smoking whilst on the combined oral contraceptive pill significantly increases the risk of DVT (deep vein thrombosis) in the major leg veins.

Intermittent Claudication

• People with narrowed arteries in the legs often develop cramps in the calves during exercise (intermittent claudication). This happens because oxygen consumption in the calf muscle has outstripped the body's ability to supply it
• Smoking worsens the supply of oxygen to the muscles making the blood more sticky, so that fewer red blood cells can pass down the narrowed arteries. Nicotine also stimulates the arteries in the legs to constrict, again contributing to a reduced peripheral circulation in the presence of narrowed arteries
• Stopping smoking can significantly reduce claudication symptoms, improving exercise tolerance

Leg Ulcers

• Ischaemic leg ulcers are much more common in smokers with peripheral vascular disease. Not only are these ulcers less likely to heal, but they are more likely to progress to gangrene requiring amputation

Digestion

• Nicotine stimulates the production of gastric acid in the stomach and duodenum. Smokers have an increased risk of developing stomach ulcers because of this.

Skin

• Nicotine denatures Vitamin C so that most smokers are chronically Vitamin C deficient. Vitamin C is necessary for protein repair in the skin.
• It has been suggested that smoking for 10 years adds another 4 years to how old you look - mainly in the number of skin wrinkles and creases, but also in the peripheral perfusion of your skin.
• Smoke for 20 years - add an extra 8 years. Smoke for 30 years - add 12 years.
• The worrying thing is that if vitamin C deficiency shows on the outside as aging of the skin, what is it doing to the organs on the inside - are they biologically older as well?.

Healing

• Smokers take longer to heal after surgery or any other traumatic event. They are deficient in Vitamin C, an essential vitamin for protein repair
• A smoker's circulation is sluggish in the peripheries causing a reduction in oxygen supply to healing tissue, and their blood carries less oxygen because of high levels of carbon monoxide.

Anaesthetic Risk

• As you can see above, smoking affects nearly every system in the body. Having an anaesthetic as a smoker carries an increase risk of the following:
  1. Heart attack, stroke, leg thrombosis, pulmonary embolism (clot in the lung)
  2. Post-operative chest infection, lowered blood oxygen levels requiring oxygen therapy
  3. Wound dehiscence (burst wound caused by coughing), wound infection with delayed healing
• If you are going to have an operation, it is sensible to stop smoking at least 6 weeks beforehand so that some of the effects on your system can reverse. However, there is no guarantee that all of the effects can be reversed.

Your Children

Before Birth

• Smoking reduces placental efficiency causing children to have low birth weight ie - starved in utero
• It also increases the risk of premature labour requiring a stay on the neonatal intensive care unit.
• Smoking may have a role to play in the development of pre-eclampsia.

After Birth

• Children whose parents smoke (passive smoking) are 6 times more likely to develop chronic chest complaints like asthma, recurrent chest infections, and also glue ear.

Cancer Risk

• Smoking has been associated with an increase risk of developing the following types of cancer:
  1. Lung - can spread early to the bones and spine
  2. Mouth (tongue), Pharynx (throat), Oesophagus (gullet), Stomach
  3. Kidney, Bladder, Cervix, Vulva (outer lips), Penis
• You can see a sort of pattern to these areas. They all have contact with toxins present in tar - either on the way into the body, or on the way out.