7-22-05

 

High-Altitude Sickness



What is high-altitude or mountain sickness?

Sometimes people get sick at high altitudes, such as in the mountains. This is called mountain sickness or high-altitude sickness.

What causes this problem?

Lack of oxygen causes high-altitude sickness. As altitude increases, the air becomes "thinner," which means less oxygen is in the atmosphere. You get less oxygen in your lungs with each breath, so the amount of oxygen in your blood declines. (This is called hypoxia) (hi-POKS'e-ah). All people can experience mountain sickness, but it may be more severe in people who have heart or lung problems.

What are the symptoms?

Symptoms usually begin within 48 hours of arriving at high altitude. The higher the altitude, the greater the effects. People can notice effects when they go to an altitude of 7,000 to 8,000 feet. If you have heart disease (such as heart failure) or lung disease (such as emphysema), you may have symptoms at lower altitudes. Symptoms include

Both heart rate and breathing rate increase as the body tries to send more oxygen to its tissues. At very high altitudes, body fluid can leak into the brain (called brain or cerebral edema) or into the lungs (pulmonary edema). Both these conditions can be serious or even life-threatening.

 

AHA Recommendation

The best way to avoid or lessen the effects of mountain sickness is to increase altitude slowly. Climbers and hikers can take two days to reach 8,000 feet, and then another day for each 1,000 to 2,000 higher feet. This may not be an option for people who travel to a destination at high altitude. Most people can adjust or "acclimatize" to the high altitude within a few days. Here are some tips:

If you have a heart or lung condition, consult your physician before going to high altitude. He or she can tell you whether your condition will let your body adjust to the lower oxygen in the atmosphere.



 

 

This information was obtained from the American Heart Association website:  www.americanheart.org

 

 

 

Cold Weather and Cardiovascular Disease


AHA Recommendation

People who are outdoors in cold weather should avoid sudden exertion, like lifting a heavy shovel full of snow. Even walking through heavy, wet snow or snow drifts can strain a person's heart.

How does cold weather affect the heart?

Many people aren't conditioned to the physical stress of outdoor activities and don't know the dangers of being outdoors in cold weather. Winter sports enthusiasts who don't take certain precautions can suffer accidental hypothermia (hi"po-THER'me-ah).

Hypothermia means the body temperature has fallen below normal. It occurs when your body can't produce enough energy to keep the internal body temperature warm enough. It can kill you. Heart failure causes most deaths in hypothermia.

Symptoms include lack of coordination, mental confusion, slowed reactions, shivering and sleepiness.

Children, the elderly and those with heart disease are at special risk. As people age, their ability to maintain a normal internal body temperature often decreases. Because elderly people seem to be relatively insensitive to moderately cold conditions, they can suffer hypothermia without knowing they're in danger.

People with coronary heart disease often suffer chest pain or discomfort called angina pectoris (AN'jih-nah or an-JI'nah PEK'tor-is) when they're in cold weather. Some studies suggest that harsh winter weather may increase a person's risk of heart attack due to overexertion.

Besides cold temperatures, high winds, snow and rain also can steal body heat. Wind is especially dangerous, because it removes the layer of heated air from around your body. At 30 degrees Fahrenheit in a 20-mile-per-hour wind, the cooling effect is equal to calm air at four degrees. Similarly, dampness causes the body to lose heat faster than it would at the same temperature in drier conditions.

To keep warm, wear layers of clothing. This traps air between layers, forming a protective insulation. Also, wear a hat or head situde sickness. As altitude increases, the air becomes "thinner," which means less oxygen is in the atmosphere. You get less oxygen in your lungs with each breath, so the amount of oxygen in your blood declines. (This is called hypoxia) (hi-POKS'e-ah). All people can experience mountain sickness, but it may be more severe in people who have heart or lung problems.

What are the symptoms?

Symptoms usuall y beg in within 48 hours of arriving at high altitude. The higher the altitude, the greater the effects. People can notice effects when they go to a n altitude of 7,000 to 8,000 feet. If y ou have heart disease (such as heart failure) or lung disease (such as emphysema), you may have symptoms at lower altitudes. Symptoms include headaches, breathlessness, fatigue Heat and humidity interfere with the body's natural cooling process.

Exercising outside in hot and humid conditions can be hard on your heart. This is true even for athletes who haven't yet adapted to the heat. The problem is made worse because the heart is trying to deliver blood and oxygen to your working muscles while your body is trying to cool off by sweating. If you sweat too much, you lose fluid. This decreases your total blood volume. That means your heart has to pump even harder to get the smaller volume of blood to your working muscles, skin and the other body parts. When you lose too much fluid, your body temperature rises and your nervous system doesn't work properly. Extreme fluid loss can lead to brain and heart damage.

A good way to monitor your body fluid level is to weigh every morning after using the bathroom. If you weigh two pounds less than normal in the morning, you're probably dehydrated and need to drink more water before doing any vigorous physical activity. (You may have lost weight as water but not as fat.)

If you plan to exercise outside in hot and humid weather, wear very light, comfortable clothing and work out in the early morning or late evening, if possible. Know the symptoms of heat exhaustion and heat stroke. If any symptoms appear, stop exercising and cool down immediately by dousing yourself with cold water. You may need to get medical attention. Heat exhaustion can progress quickly to heat stroke, which can kill you.

What are the symptoms of heat exhaustion?

What are the symptoms of heat stroke?

 

 

This information was obtained from the American Heart Association website:  www.americanheart.org

 

 

 

 

 

 

Physical Activity


AHA Scientific Position

Physical inactivity is a major risk factor for developing coronary artery disease. Coronary artery disease is characterized by deposits of fatty substances, cholesterol, calcium and other substances in the inner lining of arteries that supply blood to the heart muscle. It also contributes to other risk factors, including obesity, high blood pressure, high triglycerides, a low level of HDL ("good") cholesterol and diabetes. Even moderately intense physical activity such as brisk walking is beneficial when done regularly for a total of 30 minutes or longer on most days.

Why is exercise or physical activity important?

Regular aerobic physical activity increases your fitness level and capacity for exercise. It also plays a role in both primary and secondary prevention of cardiovascular disease. Physical inactivity is a major risk factor for heart disease and stroke and is linked to cardiovascular mortality.

Regular physical activity can help control blood lipid abnormalities, diabetes and obesity. Aerobic physical activity can also help reduce blood pressure.

The results of pooled studies show that people who modify their behavior and start regular physical activity after heart attack have better rates of survival and better quality of life. Healthy people -- as well as many patients with cardiovascular disease -- can improve their fitness and exercise performance with training.

How can physical activity help condition my body?

How can I improve my physical fitness?

Programs designed to improve physical fitness take into account frequency (how often), intensity (how hard), and time (how long). They provide the best conditioning.

The FIT Formula:

F = frequency (days per week)

I = intensity (how hard, e.g., easy, moderate, vigorous) or percent of heart rate

T = time (amount for each session or day)

AHA Recommendation

For most healthy people:

For health benefits to the heart, lungs and circulation, perform any moderate-to-vigorous-intensity aerobic activity for at least 30 minutes on most days of the week at 50-75 percent of your maximum heart rate. You can accumulate 30 minutes in 10 or 15 minute sessions. What's important is to include physical activity as part of a regular routine.

These activities are especially beneficial when done regularly:

The training effects of such activities are most apparent at exercise intensities that exceed 50 percent of a person's exercise capacity (maximum heart rate). If you're physically active regularly for longer periods or at greater intensity, you're likely to benefit more. But don't overdo it. Too much exercise can give you sore muscles and increase the risk of injury.

What about moderate-intensity activities?

Even moderate-intensity activities, when performed daily, can have some long-term health benefits. They help lower the risk of cardiovascular diseases. Here are some examples:

What risk factors are reduced?

Regular physical activity can also help reduce or eliminate some of these risk factors:

What are other benefits of physical activity?

When should I consult my doctor?

Some people should consult their doctor before they start a vigorous exercise program. See your doctor or other healthcare provider if any of these apply to you:

If none of these is true for you, you can start on a gradual, sensible program of increased activity tailored to your needs. If you feel any of the physical symptoms listed above when you start your exercise program, contact your doctor right away. If one or more of the above is true for you, an exercise-stress test may be used to help plan an exercise program.

(This list was developed from several sources, particularly the Physical Activity Readiness Questionnaire, British Columbia Ministry of Health, Department of National Health and Welfare, Canada, revised 1992.)

 

This information was obtained from the American Heart Association website:  www.americanheart.org

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