Exercise Program Designing
Heat & Humidity
Heat & Humidity
Exercise in an environment that is hotter than body is accustomed to, can imperil the ability to properly thermoregulate.Prolonged exposure results in a slowly increase in body's temperature which results in heat illness. Sweating is the first defense mechanism to maintain body temperature, but sweating also causes dehydration. Sweat that evaporates from the skin is more effective at cooling than sweat that drips off the body. So even though person may be sweating profusely, there is a risk of severe heat problems. Our Second method to maintain temperature is convection & radiation (transfer of heat to air current), in this method superficial veins in the skin dilates. Emergencies from heat occur in three forms; heat cramps, heat exhaustion and heat stroke. The most serious heat illness is heat stroke.
Exercise guildelines in heat and humid enviroment.
• Drink water before, during and after exercise sessions. Drink 16 fl oz (473 ml) for every 1 lb (0.5 kg) lost.
• Check your urine color. Urine should be clear to pale yellow, and there should be a large amount if you are drinking
adequately. You should urinate every 2 to 4 hours during an activity when you are staying properly hydrated. If your urine color is dark, then you have dehydrated yourself.
• Do not drink caffeine or alcohol-they increase blood flow to the skin and increase your risk of dehydration.
• stay cool when possible. Take frequent breaks in the shade, by a fan, or in air-conditioning.
• Schedule your exercise time to the coolest portions of the day
• Wear a hat to shade the top of the head.
• Use cold water, because absorption rate is faster with cold water.
• Acclimate yourself properly to heat/humidity over 7-14 days.
• Wear cotton material (clothing).
• Use light and bright colored clothing.
• Follow the WBGT (wet bulb globe temperature), it is an index of environmental conditions. If WBGT value is greater than 88F, then postpone or discontinue the exercise.
• Keep on clearing your sweat if environment is very hot and humid.
Prolonged exposure to cold may result in hypothermia, or abnormally low body temperature. Body temperatures that drop too low affect the brain an make it difficult to think clearly or move quickly. Hypothermia is dangerous because you may not know it's occurring until it's too late. Very cold environments can also cause physiological stress to the body. The main priority in chilly climates is maintaining body heat to avoid conditions like hypothermia and frostbite. The biggest dangers in cold weather include frostbite and hypothermia. Frostbite is a cold-related injury characterized by the actual freezing of tissue. Heat conservation is the major goal when exercising in cold climates. Hypothermia is dangerously low body temperature, below 95F (35C).
Signs of Hypothermia
• Shivering / exhaustion
• Confusion / fumbling hands
• Memory loss / slurred speech
Signs of Frostbite
• The first signs are redness or pain in any skin area. Other signs include:
• A white or grayish-yellow skin area
• Skin that feels unusually firm or waxy
• People are often unaware of frostbite until someone else points it out because the frozen tissues are numb.
• Early warning signs include tingling and numbness in the fingers and toes or burning sensations in the nose and ears.
Exercise guildelines when exercising in extreme cold
• Increase your intake of complex carbohydrate because the glycogen depletion is caused by two factors: first shivering, which causes muscles to empty their glycogen stores at 5-6 times the normal rate; secondly, increased blood levels of epinephrine (adrenaline), a hormone which stimulates glycogen breakdown. Winter also increases fat oxidation, but extra dietary fat is unnecessary.
• Wear enough clothing to stay warm as you exercise but not so much that you begin to sweat heavily.
• Water is lost from the respiratory system at an augmented rate on chilly days, and exposure to cold air can also increase urine production.
• Prevention of cold injuries requires a balance between exercise intensity and the insulating effect of protective clothing.
• Wear a mask or scarf to warm cold air before breathing it.
• For asthmatic people, take asthma medication 15-30 minutes before skiing, snowboarding, ice skating, etc.
• Warm-up 30-60 minutes beforehand, then stop.
• Those with frostbite should not rub or massage the frozen tissue.
• Your head should be covered while exercising in the cold, because heat loss from the head and neck may be as much as 50 percent of the total heat being lost by your body.
• Avoid alcohol, Alcohol dilates blood vessels and increases heat loss so the odds of experiencing a hypothermic event increase.Also avoid coffee.
• Do not wait for thirst, drink water before, during and after exercise.
• The immediate treatment for cold injuries is immersing the affected area in warm (103 [degrees] to 105 [degrees] F water.
Altitude is the elevation of an object from a known level. As altitude increases, the number of molecules of air decreases, which results in a reduction in the pressure that the gases exert. This fact is very important since gases (oxygen) diffuse based upon pressure gradients. The lower pressure of oxygen in the air results in less oxygen in the blood and the muscle tissues. At altitude, the following conditions are present:
1. Air temperature decreases about 2?F for every 500 feet.
2. Colder air holds less moisture, so the air is drier.
3. Increased solar radiation.
When exposed to moderate altitudes (greater than 7,000 feet), many individuals experience symptoms that have been referred to as "altitude sickness," A symptom of altitude includes headache, nausea, irritability, labored breathing, weakness, dizziness, insomnia and a decreased appetite. These symptoms may occur within a few hours of exposure to altitude and usually dissipate within 24 to 48 hours. The major change that occurs with acute altitude exposure is a reduction in cardiovascular capacity. There appears to be little change in cardiovascular capacity below 5,000 feet; however, there is approximately a 10 to 11 percent reduction in cardiovascular capacity for every 3,000 feet beyond this altitude.
Exercise guidelines at altitude.
• Limiting physical activity for the first few days may also help to complete the exercise without becoming exhausted.
• Exercise at reduce intensity and allow time for a gradual warm-up & cool down.
• Avoid alcohol and caffeine (it dehydrates our body).
• A high (Complex) carbohydrate diet helps to maintain hydration and provides energy to muscle.
• Maintaining adequate hydration may also help reduce the symptoms of acute altitude sickness.
• Two drugs, acetazolamide and dexamethasone, have been shown to alleviate the symptoms of acute altitude sickness once they occur.
• If the condition becomes unusually severe, descent to a lower altitude is recommended.
• Human bodies have built-in adjustment mechanisms that can optimize performance at higher altitudes. This process is known as acclimatization. It is usually complete within 2 weeks.
• Since there is less oxygen in the air at higher altitude, heart will beat faster at any given submaximal intensity to deliver adequate oxygen to the muscles, even at rest.
Air pollutants can cause complications for outdoor exercisers, depending upon the types and levels of pollutants and individual susceptibility. Air pollution is a little known environmental variable that individuals should consider during exercise sessions outdoors. At rest, an average person breathes approximately 600 liters of air/hour. Exercise ventilations can reach in excess of 7,000 liters/hour. Thus, any pollutants in the ambient air are likely to be inhaled and come into contact with lung tissue and other tissues, such as those in the cardiovascular system. During exercise, however, nasal breathing is limited; most exercisers breathe through their mouth. Because air filtration is much less efficient with mouth breathing, more pollutants are able to reach the lungs.
In addition to temperature, humidity and altitude, air pollution can affect exercisers - particularly those who exercise in densely populated urban areas affected by traffic and industry. The major air pollutants are ozone, carbon monoxide and sulphur dioxide. The major factors in determining effect are concentration of pollutant, duration of exposure and the volume of air inhaled.
Types of Air Pollutants
Ozone - a colorless, odorless gas that is formed from the combination of heat, sunlight and various chemicals that are emitted from automobiles and industry. This pollutant has been found to cause breathing problems, eye irritation and nausea. Long-term effects of ozone on lung function currently are being studied.
Carbon monoxide - a colorless, odorless gas produced from automobile exhaust. It lowers the amount of oxygen in the blood, which ultimately limits the amount of oxygen that is transported to working muscles.
Sulphur dioxide -a primary respiratory pollutant produced from burning coal that can cause breathing difficulties, especially in people with asthma.
Suspended particles - solid matter in the form of smoke, dust and vapor that is produced from diesel exhausts, wood burning, fires and farming, etc. Particle pollution can irritate the lungs and even has been linked to premature deaths from heart and lung ailments.
Exercise guidelines in Air Pollutants
• Ozone levels in cities are usually lowest in winter and peak during afternoon hours in late summer and early fall.Carbon monoxide, on the other hand, is usually highest directly at the source - vehicular emissions. Therefore, it is not recommended to exercise during or near heavy traffic.
• Immediate symptoms of breathing noxious pollutants include coughing, chest pain, wheezing and reduced breathing ability. Long term exposure is believed to cause chronic lung and heart diseases and reduce immunity to diseases.
• People who are most susceptible to air pollutants include children, elderly, asthmatics and those with heart or lung disease. Also, some people have allergic reactions to dust or specific chemicals.
• If you are exercising where there is moderate air pollution, it is recommended to reduce the intensity of exercise to decrease the volume of ventilated air. Exercising indoors during episodes of severe pollution is the safest option.
• Gather information about air pollutants level from official government agencies. Follow the PSI (pollution standard index), it should be above 100 for unfit people to exercise, above 150 for healthy people.
• Avoid exercise during rush hours.
• Avoid cigarette smoking, alcodol, coffee prior to and during exercise.
• Avoid combinations of high temperature, humidity and air pollution.
• Air pollution reduces the oxygen carrying capacity in the presence of carbon monoxide.
• Do train early in the day or in the evening.
• Hydrate your body properly.
• In pregnant women the fetus is especially vulnerable to the effects of the mother's inhalation of carbon monoxide.