Tuesday, September 7th, 2010
Exercise Right!
EXERCISE AND CARDIOVASCULAR DISEASES
Multiple studies have been done on the association between exercise and cardiovascular diseases. The earliest study was done by a British physician who looked at cardiovascular disease rates in conductors and drivers in the London Public Transit system. The conductors were more active physically than the sedentary bus drivers. The British researchers found the heart attack rates to be twice as high in the inactive bus drivers compared with the active conductors. Other British researchers looked at the heart attack rate in the postal workers who delivered the mail and compared it with the postal workers who sorted mail. Again the same phenomenon was noted. The physically active postal workers had half the heart attack rate of the inactive postal workers. At least 5 other major studies have been conducted and they all show the same thing, that is, physically inactive persons are 2 to 3 times more likely to die of a heart attack than physically active persons.
THE PHASES OF AN EXERCISE SESSION
THE WARM-UP PHASE
The purpose of the "warm-up" is to make the exercise session safer. If a person begins exercising without warming-up properly, there is an exaggerated increase in the blood pressure and heart rate response. A good warm-up provides enough time for your circulation to adjust to the increased oxygen demands of your heart during exercise. The arteries feeding the muscles of the body need to have time to dilate and allow extra blood flow to the muscles. Warming-up allows the muscles, tendons, joints, and ligaments of the body to become more flexible reducing the risk of injury and discomfort. You must bend and stretch the muscles you will use later in your exercise session. Warm-ups should last 5-10 minutes and can be:
1. Light , easy stretches
2. Light calisthenics
3. Slow walking
4. Biking with no resistance
THE AEROBIC PHASE
"Aerobic" means with oxygen. Aerobic exercise is physical exercise that uses the body's large muscle groups continuously and steadily over time to produce beneficial changes in the respiratory and circulatory systems. Using oxygen for energy production allows you to exercise at moderate, comfortable levels for a longer time so that these cardiovascular benefits can occur. But the other reason the benefits occur is because you are burning calories or expending energy when you exercise aerobically. A certain amount of calories per week must be "burned" to achieve results. The optimal amount of calories burned from exercise per week should total approximately 2,000 to 2,400 calories. This is associated with an increased protection against heart attack. This goal is equivalent to exercising about an hour a day for 5 days. The calculation of optimal amount of calories burned from exercise depends on the following four factors:
1. Type of aerobic exercise: Walking, biking, rowing, jogging,
swimming, aerobic dancing, cross country skiing, hiking, jumping
rope, running in place.
2. Frequency of exercise 3-5 exercise sessions per week.
3. Intensity of exercise enough to feel like a comfortable challenge
and increase your heart rate to your target heart rate.
4. Duration of exercise 20-60 minutes for each exercise session.
THE COOL-DOWN PHASE
During exercise, the motion of the arm and leg muscles (relaxing and contracting) pumps blood back to the heart through the veins. When you stop exercise, blood is concentrated in the arm and leg muscles. "Cooling-down" prevents the pooling of blood that could lead to a large drop in blood pressure. Also, cooling-down will allow the heart rate to slow down gradually from exercising levels so less oxygen will be needed by the heart muscle. Again, cool-downs should last 5-10 minutes and can be:
1. Slow walking
2. Light, easy stretches
3. Light calisthenics
4. Biking with no resistance
PERFORMANCE SAFETY FACTORS
Exercise should be comfortable, safe, and effective. Certain things should be kept in mind to keep it that way. You should pay particular attention to:
1. Failing to warm-up and/or cool-down adequately. Sudden strenuous exercise puts a greater demand on the heart muscle and will put your muscles, tendons, ligaments and joints at risk for injury. The transition time to exercise and after exercise must be gradual.
2. Exercising to the point of heat exhaustion. When you exercise, heat is generated by your body. Blood picks up heat from your working muscles and transfers it to the blood vessels near the surface of your skin to be evaporated off as perspiration. To avoid dehydration, drink water before, during, and after an exercise workout (cooler water is absorbed more quickly into your system). It is also important to wear the right clothing to prevent heat exhaustion.
3. Exercising in excessive heat and/or high humidity. Hot temperatures mean there will be more heat for the body to have to deal with and get rid of. If high humidity is added to this, the body has a greater job of trying to keep you "cool" while you exercise because there is already a lot of moisture in the air and perspiration will not be easily evaporated. Drinking enough fluids is especially important at the times to stay cool. It is probably better to exercise indoors or wait for the time of day the heat and/or humidity is the lowest.
4. Exercising when you have an illness causing a fever or if you have a fever. Illness with fever interferes with your body's natural ability to regulate its internal temperature. It is not advisable to exercise with any illness that gives you a fever because it raises your body temperature. Also your body is "working" hard to fight the illness and your energy levels will be lower. Wait until your body temperature has been normal for at least 24 hours and then gradually increase to your usual level of exercise activity over the course of a week or two.
5. Wearing inappropriate clothing. The clothes you wear when exercising in hot or even warm weather should promote heat loss. The type of clothing you wear should be light and porous. Heat-trapping clothing predisposes you to heat exhaustion and dehydration. Also, for walking or jogging you should wear shoes that foster stability and absorb shock. Shoes are now made to suit different types of feet and their needs.
6. Exercising without proper preparation in cold weather. Cold temperatures cause the skin's blood vessels to constrict in an effort to conserve body heat. This increases the heart's blood and oxygen needs because it has to beat harder to pump blood through narrower blood vessels to meet the body's needs. The aim of dressing for cold weather is to adequately insulate yourself but at the same time avoid trapping body heat and causing excessive sweating. Wear layers of clothing so that you can shed layers if you get hot or put it back on if you get cold. Wear a hood or cap and gloves because the blood vessels in these areas do not constrict in cold weather to conserve heat and you will lose body heat in this way.
7. Exercising in polluted air. The quality of the air we breathe affects your ability to work out safely. Pollutants like carbon monoxide, ozone, hydrocarbons, cigarette smoke, high levels of pollens, etc., mean less oxygen available placing a greater demand on you heart muscle needs during exercise. Exercising indoors is a good option.
8. Exercising at higher attitudes. The air pressure is lower at higher attitudes, which causes a reduction in your body's ability to filter oxygen out of the air. That means less oxygen is available in the atmosphere to supply the needs of the heart muscle and body muscles during exercise. It is advisable to exercise at lower intensities, slower pace, and less time than you may be used to at home.
9. Exercising competitively. Exercise should be recreational. The pressure and excitement of competition causes a release of adrenaline, speeding up your heart rate and increasing your blood pressure. This places a greater demand on your heart. Everyone has individualized needs for exercise. Reaching your individual potential and obtaining the best cardiovascular benefits for yourself should be your goals.
10. Exercising infrequently. There is a greater risk for the heart patient who exercises inconsistently. The benefits of aerobic exercise are achieved and maintained only with regular exercise. A greater effort is placed on your heart and body when you workout in a "hit or miss" fashion and you will be placing yourself at greater risk for complications.
11. Exercising right after a meal. A good amount of blood is diverted to your stomach and intestinal tract to aid in the digestion of a meal. Exercising right after a meal means there will be a "competition" to supply both your heart and the stomach and intestines with the blood they need to do their work. The heart muscle and muscles of the body need a good supply of blood to do their job. It is advisable to wait a hour or so to allow digestion to take place before you exercise so as not to put undue demand on your heart. Listen to your body when you exercise. Exercise should be comfortable and safe.
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