On August 8, 2008, the Beijing Olympics opened. In addition to the highly publicized doubts about whether all sports facilities will be ready in time, the various national Olympic Organizing Committees were concerned about what environmental conditions their competitors would expect. The whole world knew that it would be very hot.
The whole world knew that it would be very hot. But now that the game is over, it's clear to everyone what it means to play in one of the most polluted cities. (1)
Many experts predicted that respiratory problems among athletes would take on new dimensions and catastrophically worsen the symptoms of athletes suffering from asthma.
Nevertheless, it was also claimed that participation in the Beijing Games was not more damaging to the health of the athletes than, for example: For example, a corresponding participation in London. However, this debate also highlighted something else: namely the growing concern about the negative effects of air pollution on urban residents - and especially on athletes.
For athletes among us who live and work in the city, the ability to breathe in a cocktail of harmful substances has already become a real health risk. Already in the medical literature connections between the air pollution and lungs (2) and cardiovascular diseases (3) and even cancer (4) are produced. For example, increased air pollution is closely related to an increased rate of asthma (5) as well as an acute deterioration in the condition of patients with cardiovascular disease (2, 6).
In 2003, a study was presented at the American Heart Association meeting. This showed a clear correlation between the death rate from cardiovascular diseases and the pollutant concentration in the air. (3) For example, the number of premature deaths due to air pollution is estimated at 19 per 100, 000 inhabitants throughout Europe. (1)
Although these death rates refer to patients with pre-existing conditions, they do show the serious effects of air pollution. In addition, the growing evidence that there is a link between air pollution and the development of generally debilitating or even life-threatening illnesses is a matter of concern for all of us.
Although the harmful effects of air pollution are now well known, there is no direct evidence of the long-term health effects of training in an environmentally-polluted environment. However, common sense suggests that if 10 times more air is inhaled through the lungs during exercise, the pollution caused by air pollution is 10 times greater. In other words, during a 1-hour workout, the load equals the load during a 10-hour rest period.
To make things even worse: While exercising, you breathe through your mouth rather than through your nose. This allows the air to bypass the natural protective mechanism against the inhalation of harmful particles - the ingenious filtering system that sits between the nose and throat.
To do the job, we breathe much deeper and faster than normal during exercise, transporting all particles and pollutants to the farthest corners of the lungs. Really scary!
What pollutants really cause concern, and how can people living in the city find out about the daily risks of outdoor sports?
Most television and radio stations today report air pollution, especially during the summer months, when "photochemical smog" becomes a problem. Pollutant levels are numbered as follows and then grouped into classes with appropriate health risks:
- Low (1-3) : impairments are barely noticed; not even by very sensitive people.
- Moderate (4-6) : Sensitive individuals may feel mild discomfort; however, these usually do not need to be addressed.
- High (7-9) : Sensitive people may feel strong impairments, which may need to be treated.
- Very high (10) : The impairments of sensitive persons can get worse.
In developed countries, pollutants in the air are mainly caused by exhaust fumes and are highest in urban areas. (With one exception: ozone levels are highest in rural areas near the city, as ozone is a very mobile gas.) Pollutant levels are determined on any given day in any city by a combination of factors, not just traffic.
For example, cities like Beijing B. due to infrastructural conditions relatively high pollutant levels. Beijing is an industrialized, densely populated city surrounded by mountains. In summer, photochemical smog is formed during the day under strong sunlight and is held there by the surrounding mountains. The smog is intensified daily by the high pollutant emissions of traffic.
Other notorious smog hotspots include Athens, Bangkok, London, Los Angeles, Mexico City, New Delhi, New York, Paris, Santiago, Chile, Sao Paulo, Sydney and Vancouver. Taking into account that the 2004 Olympic Games took place in Athens and will take place in London in 2012, it becomes clear that the discussion on high performance air pollution has been, is and remains.
Not all vehicle emissions are harmful. However, the following 6 pose all health or performance-damaging risks:
- Carbon monoxide (CO)
- Nitrogen dioxide (NO2)
- Ozone (O3)
- Fine dust (PM10)
- Sulfur dioxide (SO2)
- volatile organic compounds (FOV)
Consequences of the continuous load
Although some contexts have been made earlier in the text, the full impact of the pollutant cocktail that city dwellers breathe on a daily basis and the consequent on-going burdens are largely unexplored. There is much to suggest that FOVs, such as benzopyrene as a known carcinogen, pose a long-term health risk. FOVs are involved in the formation of the photochemical smog-associated blue-brown haze and continue to cause irritation of the eyes and the respiratory tract.
In terms of immediate respiratory and oxygen transport system damage, high levels of carbon monoxide (CO) appear to reduce the oxygen transportability of the blood, the maximum oxygen uptake capacity, and the lactate threshold. The CO concentration decreases as more cars are equipped with catalytic converters. On busy roads, however, high values are measured and maximum values are reached in slow-moving vehicles - with direct effects on athletes who drive to their competitions in the car.
The fine dust problem
The air pollution information also includes information on particle concentrations less than 10 microns in size, called PM10 or particulate matter. PM10 is of concern as it can be stored in the back of the lungs. It reaches maximum values in smog phases and on roadsides. The combination of PM10, sulfur dioxide and water vapor combine to form sulfuric acid particles that are deposited deep in the lungs, with relatively obvious consequences (irritation and asthma-like symptoms). The actual particles consist of various compounds, including carcinogenic hydrocarbons and lead.
The deep and rapid breathing during exercise favors the deposition of PM10 in the lungs; This exposes athletes to increased risk. In Oslo, residents of more polluted neighborhoods have been shown to be at increased risk of lung cancer, but the full impact of PM10 exposure is currently unexplored. (4)
Nitrogen dioxide (NO2) and sulfur dioxide (SO2) are highly soluble gases that are converted into nitric and sulfuric acids through contact with moisture in the mouth and lungs. They cause irritation and pain in the nasopharynx and lungs, cough, shortness of breath and cause asthma symptoms in both healthy people and asthmatics. Fortunately, the values for these two gases are usually relatively low and the symptoms described are very rare.
Unfortunately, one can not say the same about the ozone content (O3). On the one hand, this is good for the stratosphere, where it filters out UV radiation. Near the ground (the troposphere), however, a high ozone content is poor. O3 is formed by the action of strong solar radiation on other atmospheric pollutants (mainly FOV and NO2). Therefore, the ozone concentration is highest in summer. Since O3 is a very mobile gas, the highest concentrations are usually detected in rural areas close to the city. Like NO2 and SO2, O3 also causes asthma-like symptoms and irritation of the lungs. In addition to direct irritation of the lungs, O3 also affects the nervous system, blocks breathing; Deep breaths become so difficult and painful. There is much to suggest that this reaction is a protective reflex to protect the lungs as much as possible from this irritation.
Studies have shown that the response to ozone depends on concentration, duration of exercise, and respiratory intensity. (7) This means that the effects of exercise are intensified. Furthermore, the responses to O3 appear to be very different from person to person. Some individuals show a marked reduction in their lung function, while others show little or no harmful effects. (8, 9)
The effects of ambient ozone concentration were explored in a study of amateur cyclists in the east of the Netherlands over a summer competition season. (10) The authors found a strong correlation between environmental ozone concentration and post-workout cyclists' lung function. There were also symptoms such as wheezing, narrowing of the chest and shortness of breath (worst when the ozone concentration was highest). This relationship persisted after results were withdrawn for concentrations above 60 ppb (parts per billion). Therefore, it was considered that adverse effects persisted even on days when ozone concentration was considered moderate.
Ozone for asthmatics
It has previously been thought that asthmatics are more sensitive to O3 than those with normal lung function due to the previous inflammation of their lungs. (11) Interestingly, recent evidence suggests that this is not the case and that the severity of asthma does not indicate that it is There is, however, evidence that inflammation of the lung as a result of O3 exposure is more severe in asthmatics. (14) This inflammation can have both long-term effects and immediate acute deterioration of the respiratory tract Health status. (12)
It has also been shown that O3 exposure in asthmatics leads to a greater response to other respiratory irritants, such as: From SO2. Therefore, it may be misleading to consider the negative effects of only one isolated pollutant in laboratory studies. (15)
Since O3 triggers an inflammatory reaction in the lungs, it is believed that strengthening the natural antioxidant capacity of the lung helps to better withstand the oxidative stress of inhaling O3. In 2 Dutch studies with the same group, the cyclic function of cyclists taking antioxidative vitamins (about 100 mg of vitamin E and 500 mg of vitamin C) was evaluated before and after training or competition. (16, 17)
The addition markedly reduced the O3-related deterioration in lung function in both studies. These data are corroborated by a study of road workers in Mexico City, whose impairment in pulmonary function could also be reduced by a similar addition. (18)
So far, we have only considered health-related aspects of ozone pollution. However, there is also extensive evidence that O3 is affecting athletic performance. (19) New results from a previously unpublished study from Napier University in Scotland indicate that the performance of runners in an 8-kilometer time trial at an ozone concentration deteriorated by about 1% from 100 ppb. This corresponds to the ozone concentration of a large city in midsummer. Athletes participating in the study also suffered from impaired lung function, cough and difficulty breathing after the run. However, after antioxidant preparations were given for a second time trial - also at 100 ppb O3 - the performance again corresponded to the control time.
Although a 1% drop in performance during the time trial does not sound so bad, this could have catastrophic consequences for a world-class athlete at a major event. And although ozone levels in the UK are usually low to moderate, they hit record highs (125 ppb) during the heat wave last summer in big cities like London.
Meanwhile, you will probably wonder if it is not too dangerous to train only supposedly "fresh" air. But life is about weighing risks. Yes, you can endanger your health by jogging along a two-lane road or riding a bike to work. But you can be run over by a car even without sports tomorrow. The trade-off is to choose the time and place for your training. And remember that air quality is worst in urban areas; especially near busy and clogged roads (O3 being the exception).
You can minimize your risk without losing the enjoyment of a healthy activity if you follow these guidelines:
Do not exercise
at rush hour,
near a busy street;
in obvious smog;
at high vehicle emissions in conjunction with strong sunlight.
Do not travel in a poorly ventilated car over dusty roads for a competition (the CO concentration is highest in cars).
- Listen or read the predictions on air pollution.
- Be especially careful if you have asthma. Use your inhaler before training, and if your condition worsens, consult your family doctor as you may need other medicines.
- Consider the intake of antioxidant supplements (100 mg vitamin E and 500 mg vitamin C).
- Think about your own air filtration system. (However, compare the manufacturer's information with neutral reports, not all systems are as good as manufacturers like to believe).