Exercise & Heart Disease Risk

How much exercise should I get?

Guidelines from the American Heart Association, the National Heart Lung and Blood Institute, and various government agencies recommend a minimum of 30 minutes of moderate-intensity physical activity (e.g., brisk walking) on most, preferably all, days of the week. You can do this in three 10-minute or two 15- minute bouts, if you prefer.

What is moderate intensity physical activity?

Moderate intensity means activities that make you breathe a little deeper, but don’t leave you out of breath – you should be able to carry on a conversation. Brisk walking is an example of a moderate intensity activity. Exercise intensity is measured in metabolic equivalents or METs. One MET is the amount of effort it takes to sit quietly. Activities that take 4 to 6 METs are moderate; anything requiring more than 6 METs is considered vigorous.

For examples of activities and the energy they burn see How many calories will I burn in an hour doing various activities? An activity that is vigorous for one person may be moderate for another depending on your age and fitness level. Whatever activities you choose, go at your own pace.

Are women active enough?

No. Women are less likely to exercise regularly than men, and when women do work out, they exercise less vigorously than men. Almost 26% of women and 21% of men report no leisure-time physical activity; the numbers are even higher in some minority groups (see table below). About 30% of US women are physically active on a regular basis versus 32% of men. During adolescence, girls, particularly black girls, tend to cut back on the amount of exercise they get.

Americans Who Report No
Leisure-time Physical Activity
American Adults 24%
American women 26%
Women by Race
White 22%
African American 34%
Hispanic/Latino 40%
American Indian/Alaska Native 32%
Asian/Pacific Islander 24%

What’s the difference between physical activity, exercise, and fitness?

We tend to think of exercise as a trip to the gym or laps in the pool, but other types of physical activity such as gardening, household chores, or walking for leisure count for heart health, too. Think of exercise and physical activity as the same thing. Physical fitness includes:

  • Cardiorespiratory fitness or aerobic fitness: a measure of your body’s ability to supply fuel during physical activity. A good indicator is how far and how fast you can walk or run on a treadmill before getting winded.
  • Muscle strength: a measure of the muscle’s ability to exert force during activity. Muscle strength is developed through resistance exercises using weights or gravity, such as lifting weights or rapidly taking the stairs.
  • Muscle endurance is the ability of the muscle to perform without tiring. Repetition helps build endurance when doing exercises such as weight lifting, push-ups, or sit-ups.
  • Body composition: the relative amount of lean mass (muscle, bones, vital tissues, and organs) and fat. How lean you are is a better indicator of your fitness and health than how much you weigh. Skin fold tests (how much skin can you pinch) give an indication of your body composition.
  • Flexibility refers to the range of motion around joints. To improve flexibility, try activities that lengthen muscles such as swimming, yoga, or stretching.

Studies looking at fitness and heart health usually focus on aerobic fitness. Aerobic fitness is partly set by genetics (about 10-25%); however, the more active you are, the more fit you will become.

Exercise and Your Heart

How does exercise protect my heart?

The heart is like any other muscle – the more you work it, the stronger it gets. As the heart gets stronger, it is better able to pump blood around the body and to cope with the demands placed on it during physical exertion. Regular physical activity helps prevent some risk factors for heart disease including high blood pressure, high cholesterol, diabetes, and obesity. If you already have these risk factors, being active can stop them from getting worse. Exercise also keeps your arteries flexible (stiff arteries are prone to clogging) and can even reverse or stall the buildup of fatty plaques in the blood vessels of the heart.

Does exercise lower my risk of heart disease?

Yes. Moderate exercise (brisk walking) 30 minutes a day on most days of the week lowers your risk of developing heart disease or heart problems such as a heart attack by 30% to 50%. The Nurses’ Health Study followed more than 70,000 women aged 40 to 65 for 8 years. It found that women who walked briskly for 1 to 3 hours a week were 30% less likely to develop heart disease compared with women who did no exercise. The Women’s Health Initiative included more than 70,000 postmenopausal women. In this study, the most active women were half as likely to develop heart disease as the least-active women after about 3 years; active black women benefited just as much as active white women.

Does exercise lower my risk of dying early?

Yes. An 11-year study of nearly 100,000 women aged 30 to 49 years from Norway and Sweden found that the most active women had half the risk of dying early than the least active women. You don’t have to go for the burn to benefit. When nearly 14,000 women were followed for about 14 years, those who walked, cycled, or did light gardening 2 to 4 hours a week cut their risk of dying young by 36% compared with their sedentary peers. Older women reap the rewards, too. In a US study, postmenopausal women aged 55 to 69 years who were moderately active once a week were nearly 25% less likely to die within 7 years than women of the same age who were not active.

If I was active in my youth but am inactive now, am I still protected?

No. Unfortunately, you can’t store the heart healthy benefits of exercise. If you were active in your youth but do nothing now, you have the same risk of heart disease as a lifetime nonexerciser. The good news is that it’s never too late to start. Of the nearly 40,000 women in the Women’s Health Study, those who became active at 45 years or older cut their risk of heart disease by about 25% compared with lifetime non-exercisers. Even older women can benefit, too. The Study of Osteoporotic Fractures enrolled nearly 10,000 women 65 years and older. Women who became more active between the start and end of the study (about 6 years later) nearly halved their risk of dying early compared with women who stayed inactive.

Will I benefit from exercise if I already have heart disease?

Yes. For people who have had a heart attack, regular exercise cuts the risk of having another heart attack or dying from heart disease (see Physical Recovery After a Heart Attack or Procedure). If you have clogged arteries, you may feel chest pain (angina) during exertion; however, regular exercise actually relieves this chest pain in the long term. Exercise combined with diet and lifestyle changes can help slow down or even reverse the buildup of fatty plaque in the arteries of the heart. If you have heart disease, talk to your healthcare provider before starting an exercise program. Your doctor may refer you to a cardiac rehabilitation program that includes supervised exercise, nutritional counseling, stress management, and modification of risk factors.

Exercise – Other Health Benefits

Will exercise help me lose weight?

Exercise alone is not very effective for dropping pounds, but it is one of the best ways to trim fat and stop middle-aged spread. Exercise combined with diet is better than diet alone for losing weight and keeping it off. To lose weight, you will need to get about 60 to 90 minutes of moderate exercise most days of the week in addition to counting calories. Don’t be disheartened if the needle on the scale doesn’t budge—exercise helps you lose fat, especially troublesome belly fat, even if you don’t lose pounds. This is because exercise builds muscle and muscle weighs more than fat.

On average, US adults gain 0.4 to 1.8 pounds a year and women tend to gain more weight over time than men. Exercise helps prevent or stall age-related weight gain, especially if you are already overweight In a 10-year study of more than 15,000 adults, obese women who walked quickly for 75 to 100 minutes a week gained 9 pounds less than obese women who did not walk regularly. To prevent weight gain, you should get 60 minutes of moderate to vigorous exercise most days of the week and avoid consuming too many calories.

Does being active prevent diabetes?

Yes. Women who are more active are less likely to develop diabetes. The Women’s Health Study followed more than 35,000 women age 45 and older for nearly 7 years. The most active women cut their risk of developing diabetes by 26% compared with the least active women. In this study, the most active women burned 1500 calories or more a week in various activities. It doesn’t matter how you burn the calories: in another study of more than 70,000 nurses, walkers reduced their risk of diabetes just as much as vigorous exercisers. Lifestyle changes including diet and exercise also help prevent full-blown diabetes in men and women with early signs of blood sugar problems or prediabetes.

Does exercise help if I already have diabetes?

Yes. Aerobic exercise and resistance training (using weights or elastic bands) help women with diabetes keep blood sugar levels in check. Women with diabetes who are physically active (e.g., regular walkers) are also less likely to suffer heart problems including heart attack than sedentary women with diabetes.

Will exercise improve my cholesterol levels?

Yes. Regular exercise improves cholesterol levels mostly by increasing HDL (good) cholesterol and lowering triglycerides – another type of blood fat that raises your risk for heart disease. In a review of 51 studies, HDL cholesterol increased an average of 4.6% in men and women after 12 weeks of aerobic exercise training (e.g., walking or jogging on a treadmill, or using an exercise bike). Exercise can also lower LDL (bad) and total cholesterol, but the effects vary from person to person and depend on how high your cholesterol levels are to begin with. Even if your total and LDL cholesterol levels don’t drop, being active can stop them from getting worse. Exercise also helps change the size of the LDL cholesterol so it is less likely to clog up your arteries.

Will being active lower my blood pressure?

An aerobic exercise training program (e.g., walking or jogging on a treadmill, or using an exercise bike) lowers blood pressure, especially in people who already have high blood pressure. Exercise also prevents high blood pressure from developing in the first place. Unfit men and women are up to 52% more likely to develop high blood pressure than very fit men and women.

It is not clear whether low-intensity activities such as gardening help prevent or lower high blood pressure in women. In studies that track everyday physical activity levels, active men are less likely to develop high blood pressure than sedentary men, but this benefit has not been shown for active women. This may be because women burn fewer calories in leisure time activities than men, and the activities women choose tend to be on the lighter side.

Does watching TV increase my risk of diabetes or obesity?

The more hours in the day you spend being sedentary (e.g., sitting at a desk, driving), the less time left for being active and burning calories. While you can’t be the Energizer Bunny,® it’s important to find time every day (even 10 minutes) to get moving. In the Nurses’ Health Study, the risk of being obese or developing diabetes increased with every additional 2 hours per day spent watching TV. You burn fewer calories watching TV than with other types of sedentary behavior such as reading, writing, or driving. On top of that, TV viewing goes hand in hand with snacking. Time in front of the TV doesn’t have to be sedentary. You can pedal a stationary bike or do light weights while watching your favorite shows, or even try an exercise video or DVD.

What other health benefit does exercise have?

Besides heart disease, exercise lowers your risk for certain cancers (particularly colon cancer). Weight-bearing exercise such as walking, aerobics, or lifting weights helps prevent osteoporosis or bone thinning by keeping your bones strong. Exercise can also help you cope with stress. Being active keeps you mobile and independent into old age, and it can ease the joint swelling and pain from arthritis.

Exercise – Amount & Type

If I work out more intensely, do I benefit more?

The greatest reductions in the risk of dying early or developing heart disease occur when inactive people become moderately active (e.g., a brisk 30-minute walk most days of the week). Some studies show that there is no additional risk reduction for people who are even more active. Other studies find that the benefits are even greater the more you do.

This is probably because it’s hard to accurately measure the amount of physical activity people get. Study participants usually fill out diaries or questionnaires about the amount of time they spend each week on various activities. This method is good for separating out who does nothing from those who are active, but it’s less reliable for teasing out which active people work out more intensely.

You can burn more calories doing moderate activities for a longer time, or trying activities that are more vigorous. There is good reason to believe that doing more than the minimum recommended level would reap extra rewards because vigorous activity improves aerobic fitness more than moderate exercise. Studies that use treadmill tests to measure how aerobically fit people are show that your risk of developing heart disease or dying early continues to fall, the fitter you are.

The most important thing is to do something – find a level that works for you. Start slowly and gradually increase the amount or intensity of physical activity.

How many calories will I burn in an hour doing various activities?

The table below gives approximate calories burned in an hour for common activities; the amount varies by your weight. For metabolic equivalents (METs), Physical Recovery/Energy Levels Required to Perform Some Common Activities. Whatever activities you choose, go at your own pace. An activity that is moderate for one person may be vigorous for you, depending on your age and fitness level.

Approximate Calories Burned Per Hour in Various Activities
Type of Activity

125 lb woman

150 lb woman

175 lb woman





Basketball, recreational




Bicycling (5 mph)




Bicycling (13 mph)




Bicycling, stationary (light)




Bicycling, stationary (moderate)




Child care




Dancing, ballroom




Dancing, aerobic




Gardening, light




Golf, 2-some, carrying clubs








Light housework, cleaning, etc.








Running (12 min/mile, 5 mph)




Running (10 min/mile, 6 mph)




Scrubbing floors




Sitting, quietly




Sitting, writing, playing cards




Sleeping, laying down




Swimming (crawl 20 yards/min)




Swimming (crawl 45 yards/min)




Tennis, doubles




Tennis, singles




Walking (3 mph)




Weight lifting, light




Weight lifting, vigorous




What type of exercise should I get?

Any type of physical activity that gets you moving can help lower your risk of heart disease. Most of the studies assessing formal exercise and heart health have looked at aerobic exercise such as walking or cycling. Other types of exercise that increase strength and flexibility (e.g., weights or yoga) are important for your overall physical health and help you stay active and independent into old age. Walking is the most recommended type of exercise because it’s easy to do and has a very low risk of injury. Your healthcare provider can advise you. For example, if you have knee or joint problems, activities where your weight is supported, such as cycling or water aerobics are ideal. Being physically active in any way, including gardening and housework (sweeping floors, washing windows), helps your heart and your health – you don’t have to join a gym or follow a formal exercise program.

For more information on how to find the right physical activities for you and how to fit them into your schedule, check out the President’s Challenge Physical Activity and Fitness Awards Program (http://www.presidentschallenge.org/). If you have a disability, the National Center for Physical Activity and Disability (http://www.ncpad.org/) has some great resources, including information on a variety of exercises for people with disability, a list of accessible parks by state, a search tool for finding a personal trainer in your area, and even an exercise video for people with spinal cord injuries.

I don’t have time to exercise; what can I do?

You may not have time to go to the gym, but you can incorporate physical activity into your daily routine. If you can’t spare a full 30 minutes in one block, aim for a few 10- to 15-minute bouts each day.

  • Create opportunities for activity, such as parking your car farther away, getting off the bus before your stop and walking, or taking the stairs instead of the elevator
  • Chores count, including housework, gardening, and walking the dog
  • If you miss a few days, don’t despair; get active again
  • Set some short-term goals (e.g., walking farther) and reward yourself when you achieve them
  • Keep an exercise diary
  • Choose something that you enjoy; you’re more likely to stick with it. Get friends or family to join you.

Exercise – Risks & Precautions

Do I need to talk to my healthcare provider before I start exercising?

You should talk to your healthcare provider before beginning an exercise program if you:

  • have heart disease, have had a stroke, or are at high-risk for either
  • are middle-aged (45 to 50) or older and currently inactive
  • have diabetes or are at high risk for it
  • are taking blood pressure medication
  • are obese (body mass index [BMI] of 30 or more)
  • are pregnant
  • have a medical condition or disability that may affect your ability to exercise (e.g., knee problems, arthritis)

Your healthcare provider can help you choose suitable activities. You may be sent for an exercise stress test to determine the amount and type of exercise that is right for you.

What are the risks of exercise?

The main risks of exercise are pulled muscles and sprains. The risk of injury is higher for more vigorous activities, especially competitive sports. If you are obese (body mass index of 30 or higher, or about 30 pounds overweight for a woman of average height [5’4”]), you are more prone to injury.

Walking is a low-risk activity even for women age 70 and older. And unlike running or jogging, your risk of injury does not increase the more you walk. To avoid injury with any type of activity:

  • start out slowly and gradually build up to a level that is comfortable for you
  • stop if you feel pain
  • stretch before and after each workout
  • wear appropriate clothing including footwear and safety gear (e.g., a bicycle helmet)

What are the chances of having a heart attack or dying when exercising?

The chances of having a heart attack or dying suddenly during exercise are very low. An analysis from the Nurses’ Health Study found that the risk of suddenly dying was 1 per 36.5 million hours of moderate-to-vigorous activity. The risks are highest for people who are not active on a regular basis and are virtually nonexistent for regular exercisers. To minimize risk, anyone with heart disease or people who do not exercise regularly should begin slowly and progress gradually to meet recommended levels (30 minutes moderate intensity activity most days of the week). Experts discourage people with heart disease from participating in competitive sports that are very demanding. Remember, go at your own pace – what is moderate exercise for one person may be vigorous exercise for you, depending on your age and fitness level.


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