It is a well-known fact that smoking reduces fitness. It does
this in a number of ways, chiefly by reducing the amount of oxygen
available in the body. Since oxygen plays a major role in energy
production, even a minor depletion has an impact on physical performance.
MAJOR EFFECTS OF SMOKING ON FITNESS
David Pyne, an Australian sports physiologist, lists the major
effects of smoking on the body's respiratory and circulatory system
- High levels of carbon monoxide from smoking reduce the amount
of oxygen absorbed into the blood from the lungs.
- Carbon monoxide in the blood also reduces the amount of oxygen
that is released from the blood into the muscles.
- Smoke inhalation has an immediate effect on respiration, increasing
airways resistance and therefore reducing the amount of oxygen
absorbed into the blood.
- Smoking causes chronic (or long-term) swelling of mucous membranes,
which also leads to increased airways resistance.
- Smoking increases the heart rate for a given level of exercise.
CARBON MONOXIDE - THE MAIN OFFENDER
Carbon monoxide, the same lethal gas which is released by motor
vehicle exhausts, is present in cigarette smoke and is absorbed
rapidly into the bloodstream. The mechanisms by which it does
this are as follows:
- Once it leaves the lungs, oxygen is transported in the blood
by attaching to the haemoglobin within red blood cells. Oxygen
has a great affinity for haemoglobin. However, carbon monoxide
has a much greater affinity (200 to 300 times greater than oxygen)
and so binds preferentially to haemoglobin.
- Therefore, as the level of carbon monoxide in the blood increases,
the level of oxygen decreases.
- Raised levels of carbon monoxide in the blood also impair
the release of oxygen from the blood into the cells. This has
a significant effect on heart and other muscle cells where there
is a high demand for oxygen.
- Blood levels of carbon monoxide from smoking can also produce
distortions of time perception, psychomotor and visual impairment
and negative effects on cognitive skill.
- Oxygen is important for the functioning of all energy systems
in the body, so any mechanism which interferes with oxygen transport
and uptake interferes with energy production and therefore sports
Inhaling cigarette smoke results in airways resistance (narrowing
of air passages) in a number of ways:
- Inhalation of smoke from a cigarette can, within seconds,
cause a two to three-fold increase in airways resistance, the
rate at which air moves in and out of the lungs.
- Smoking also causes chronic swelling of the mucous membranes
of the airways, which adds to airways resistance.
- When demand for oxygen is elevated, such as during exercise,
this increased resistance is more noticeable. Reduced lung capacity
can cause a smaller volume of oxygen to reach the alveoli, resulting
in impaired gas exchange and less oxygen in the blood.
- The tar in cigarette smoke adds to airways resistance. This
tar coats the lungs, reducing the elasticity of the air sacs and
resulting in the absorption of less oxygen into the bloodstream.
- Tar also affects the cleansing mechanism of the lungs, allowing
pollutants to remain in the bronchial tubes and lungs. Increased
phlegm and coughing, and damage to the cilia (the hair-like projections
which "sweep" pollutants out of the airways) are the
EFFECTS ON THE HEART
The combined effect of carbon monoxide and increased airways resistance
is to cause the heart to work harder in an attempt to compensate
for the lack of oxygen reaching the muscles.
The nicotine in cigarette smoke also acts as a stimulant, increasing
the heart rate and blood pressure, and decreasing the flow of
blood through the blood vessels.
EFFECTS ON ENDURANCE
Smoking reduces physical endurance and impedes the improvement
in physical performance in smokers compared with non-smokers.
It also increases fatigue during and after exercise. David Pyne
noted the following:
- While exercise training can increase maximal oxygen uptake
by up to 20%, smoking can reduce this effect by up to 10%.
- In a recent study adolescents who had smoked for five days
had an 8% reduction in endurance time compared to controls.
- Individuals who smoke are less likely to continue in exercise
- A US study of more than 3,000 naval personnel found smoking
was detrimental to physical fitness even among relatively young,
fit individuals. The study also found smokers have lower physical
endurance than non or ex-smokers.
- The same study found those who smoked undertook less physical
exercise sessions each week than non or ex-smokers. They also
exercised less time per session.
- An earlier US study found that smokers had higher levels of
fatigue during both exercise and recovery. The authors believed
this increased fatigue may explain why smokers are less likely
to participate in regular exercise.
Exposure to environmental tobacco smoke either before or during
an event also impairs athletic performance.
ATTITUDES TO SMOKING & FITNESS
There have been several Australian surveys which have looked at
attitude and awareness of the association between smoking and
- A 1993 study of women who participate in aerobics found that
while 98% do so to improve fitness and enhance their physical
appearance, 15% of these women also smoke. This is despite the
fact that 75% of these women demonstrated a knowledge of the effects
of smoking on fitness.
- In the ABS 1989-90 National Health Survey on Smoking, fitness
was an important reason for quitting for those aged 25 and under.
For those aged 45 plus, it was the least important reason for
- A survey of Australian school children on aspects of health
and fitness undertaken in 1985 found that more younger children
saw being a non-smoker as important than older children (82% of
males aged 9 compared with 62% of those aged 15, and 89% of females
aged 9 compared with 54.6% of those aged 15).
- A Victorian study also undertaken in 1985 found that the majority
of post primary students agreed that smoking affected sporting
ability. Those who had used tobacco were more likely to agree.
- Improved fitness was one of the major advantages listed by
ex-smokers in a national survey on attitudes to smoking undertaken
in 1983. 40% of males and 28% of females saw improved fitness
as an important advantage.
- The National Health Survey found that smokers were more likely
to drink and not participate in regular exercise than non-smokers
or ex-smokers. Overall an estimated 2.3% of those over 18 smoked,
did not exercise and drank alcohol at medium or high risk levels.
A NSW survey showed that 13% of the population aged 15 and over
smoked, drank and did not do regular vigorous exercise. There
were more males than females (16.3% compared with 9.8%)