Exercise's Effects on the Heart

Exercise's Effects on the Heart

 

Inactivity is one of the four major risk factors for coronary artery disease. However, exercise helps improve heart health in people with many forms of heart disease and can even reverse some risk factors, such as some of the effects of smoking.

Like all muscles, the heart becomes stronger and larger as a result of exercise so it can pump more blood through the body with every beat and sustain its maximum level with less strain. The resting heart rate of those who exercise is also slower because less effort is needed to pump blood.

People who exercise the most often and vigorously have the lowest risk for heart disease, but any exercise is beneficial. Studies consistently find that light to moderate exercise is even beneficial in people with existing heart disease. However, anyone with coronary artery disease should seek medical advice before beginning a workout program.

Some studies suggest that for the greatest heart protection, it is not the duration of a single exercise session that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise, which can be particularly helpful for older people.

Resistance (weight) training has also been associated with heart protection. It may offer a complementary benefit to aerobics by reducing LDL levels. Exercises that train and strengthen the chest muscles may prove to be very important for patients with angina.

Effects of Exercise on Blood Pressure. Regular exercise helps keep arteries elastic, even in older people, which in turn ensures blood flow and normal blood pressure. Sedentary people have a 35% greater risk of developing hypertension than athletes do.

It should be noted that high-intensity exercise may not lower blood pressure as effectively as moderate-intensity exercise. In one study, moderate exercise (jogging two miles a day) controlled hypertension so well that more than half the patients who had been taking drugs for high blood pressure were able to discontinue their medication.

However, a small study published in 2005 suggests that moderate exercise does not have a significant impact on systolic blood pressure (the top number) in older adults. While those who exercised did have notable drops in both the top and lower (diastolic) blood pressure levels, the only statistically significant change was the decrease in the lower number.

Experts recommend at least 30 minutes of exercise on most -- if not all days. Studies have indicated that yoga and tai chi, an ancient Chinese exercise involving slow, relaxing movements, may lower blood pressure almost as well as moderate-intensity aerobic exercises.

Anyone with existing hypertension should discuss an exercise program with their doctor. Before starting to exercise, people with moderate to severe hypertension should lower their pressure and be able to control it with medications. They should avoid caffeinated beverages, which increase heart rate, the workload of the heart, and blood pressure during physical activity. Everyone, and especially people with high blood pressure, should breath as normally as possible through each exercise. Holding the breath increases blood pressure.

Effects of Exercise on Heart Failure. Traditionally, heart failure patients have been discouraged from exercising. Now, exercise performed under medical supervision is proving to be helpful for select patients with stable heart failure.

·      Studies continue to report benefits from exercise training. In one study, heart failure patients as old as 91 years old increased their oxygen consumption significantly after six months of supervised treadmill and stationary bicycle exercises.

·      Progressive resistance training may be particularly useful for heart failure patients since it strengthens muscles, which commonly deteriorate in this disorder. Even simply performing daily handgrip exercises can improve blood flow through the arteries.

Effects of Exercise on Stroke  

All stroke survivors should have a pre-exercise evaluation done by their doctor before starting an exercise program.

The effects of exercise on stroke are less established than on heart disease, but most studies are positive on its benefits. The following are some examples:

·      According to one major analysis, men cut their risk for stroke in half if their exercise program was roughly equivalent to about an hour of brisk daily walking five days a week. In the same study, exercise that involved recreation was more protective against stroke than exercise routines consisting simply of walking or climbing.

·      A 2000 study of women also found substantial protection from brisk walking or striding (rather than casual walking).

 

Exercise Programs for High-Risk Individuals

Anyone with heart disease or risk factors for developing heart disease or stroke should seek medical advice before beginning a workout program. Patients with heart disease can nearly always exercise safely as long as they work out under medical supervision. Still, it is often difficult for a doctor to predict health problems that might arise as the result of an exercise program. At-risk individuals should be very aware of any symptoms warning of harmful complications while they exercise.

Some experts believe that anyone over 40 years old, whether or not they are at risk for heart disease, should have a complete physical examination before starting or intensifying an exercise program. Some doctors use a questionnaire for people over 40 to help determine whether they require such an examination:

·      Has any doctor previously recommended medically supervised activity because of a heart condition?

·      Is chest pain brought on by physical activity?

·      Has chest pain occurred during the previous month?

·      Does the person faint or fall over from dizziness?

·      Is bone or joint pain intensified by exercise?

·      Has medication been prescribed for hypertension or heart problems?

·      Is the person aware of or has a doctor suggested any physical reason for not exercising without medical supervision?

 

Those who answer "yes" to any of the following questions should have a complete medical examination before developing an exercise program.

Stress Test. A stress test helps determine the risk for a heart event from exercise. Anyone with a heart problem or history of heart disease should have a stress test before embarking on an exercise program. Experts currently also recommend this test before a vigorous exercise program for older persons who are sedentary, even in the absence of known or suspected cardiovascular disease. It is expensive, however, and some experts believe that it may not be necessary for many older people with no evident health problems or risk factors. They recommend instead a carefully monitored Heart Attack and Sudden Death from Strenuous Exercise

A small percentage of heart attacks occur after heavy exertion.

High-Risk Individuals. In general, the following people should avoid intense exercise or embark on it only with carefully monitoring:

·      Strenuous physical exertion is never recommended for people who have uncontrolled diabetes, uncontrolled seizures, uncontrolled high blood pressure, a heart attack within six months, heart failure, unstable angina, significant aortic valve disease, or aortic aneurysm.

·      Older people should be cautious. Studies report that older people who first embark on vigorous exercise are at slightly higher than average risk for a heart attack during the first year, but over time, regular exercise is likely to reduce this risk.

·      Experts generally recommend that moderate or severe hypertension (any systolic blood pressure over 160 mm Hg or diastolic pressure over 100 mm Hg) should be controlled to lower levels before starting a vigorous exercise program.

·      Sedentary people should be cautious. One major study found that sedentary people who throw themselves into a grueling workout significantly increase their risk of heart attack.

·      Episodes of exercise-related sudden death in young people are rare but of great concern. Some are preceded by syncope (fainting) , which is due to a sudden and severe drop in blood pressure. It should be noted that syncope is relatively common in athletes and is dangerous only in people with existing heart conditions. Young people with genetic or inborn heart disorders should avoid intensive competitive sports.

·      Anabolic steroids or products containing ephedra have been associated with cases of stroke, heart attack, and even death.

The risk for heart attack from exercise should be kept in perspective, however. Some form of exercise carefully tailored to their specific conditions has benefits for most of these individuals. And in many cases, particularly when the only risk factors are being sedentary and older, exercise can often be increased over time until it is intense.

Hazardous Activities for High-Risk Individuals. The following activities may pose particular dangers for high-risk individuals:

·      Intense workouts (snow shoveling, slow jogging, speed walking, tennis, heavy lifting, heavy gardening) may be particularly hazardous for people with risk factors for heart disease, particularly older people. They tend to stress the heart, raise blood pressure for a brief period, and may cause spasm in the arteries leading to the heart. (See image: Coronary Artery Spasm)

·      Some studies suggest that competitive sports, which couple intense activity with aggressive emotions, are more likely to trigger a heart attack than other forms of exercise.

Listening for Warning Signs. It should be noted that according to one study, at least 40% of young men who die suddenly during a workout have previously experienced, and ignored, warning signs of heart disease. In addition to avoiding risky activities, the best preventive tactic is simply to listen to the body and seek medical help at the first sign of symptoms during or following exercise. They include the following:

·      Irregular heartbeat

·      Undue shortness of breath

Chest painprogram, starting out with low-intensity exercises and gradually building up.

 

 

Untreated hypertension

Coronary artery spasm

 

Stable angina