How Much Exercise Do I Need? (Adults aged 18-64)

There is abundant evidence about the benefits of exercise for people of all ages. Exercise improves cardiovascular health, bone strength, and reduces the risk of heart attacks, strokes and even a number of cancers. It decreases obesity as well as the risk of developing diabetes and all its complications. It improves stamina and mood. People who exercise regularly live longer. No one should be asking if they need to exercise, but rather what kind of exercise they need to do and how much exercise they should do.

There are two basic types of important exercise. One is aerobic exercise, which is the kind that burns calories and makes your heart rate go up. The other is strength training, which makes your muscles stronger.

Aerobic exercise

During aerobic exercise, your heart beats faster. This type of exercise does not include working to the point that you are completely out of breath, but just before that. It should make you breathe fast but still be able to talk, which is why it is not unusual to see people out walking while on their cell phones or in pairs chatting. If you are doing more vigorous aerobic exercise you may not be able to carry on a conversation but you should not be completely winded.

Examples of activities that can be aerobic exercise include:

  • Brisk walking
  • Jogging
  • Bicycling, outside or on an indoor exercise bicycle
  • Certain kinds of dancing
  • Specific activities designated as aerobic exercise including dance-related workouts, kick-boxing and others
  • Certain sports such as tennis and basketball
  • Parts of martial arts training
  • Swimming
  • Jumping rope
  • Hiking

How vigorous should aerobic exercise be?

This is important because the more vigorous the activity, the less time you need to spend doing it to see health benefits. If you are a healthy adult, you can almost certainly build up to very vigorous activity.

How vigorous the exercise is depends on your current level of fitness and how much energy you put into the activity. Walking can vary from relatively slow to fast “race walking.”

How do you know if your activity is very vigorous? You need to be aware of your breathing. During moderately-intense physical activity you can talk but not sing. With vigorous activity, you can only speak a few words before needing to take another breath.

For most people, walking at about 3 miles an hour is moderately-intense activity, while brisk walking at a faster pace or with hand-held weights can be vigorous activity.

In addition to evaluating your breathing, you can measure your pulse to see how vigorous your activity has been. You can measure your pulse at the wrist, on the inside above your thumb. If you are not sure how to do this, ask a friend who knows how to do it, an instructor where you are exercising, or someone at your doctor’s office. There are pulse monitors you can wear, as well as monitors attached to exercise equipment like treadmills. If you can’t do any of these things, look for a video on taking your pulse on YouTube. Usually you count the number of heart beats in 15 seconds and multiply that times four.

Moderately-vigorous activity raises your heart rate to 50% to 70% of your maximum heart rate. Your maximum heart rate is age dependent. To get this number, subtract your age from 220. To get 50% and 70%, you multiply this number by 0.5 and 0.7. You want your heart rate in between these two numbers.

For example, a 30-year-old man or woman would subtract 30 from 220 to get 190. 190 times 0.5 is 95. 190 times 0.7 is 133. At the end of an exercise session, if a 30 year old has a pulse between 95 and 133, he or she has been doing moderate-intensity exercise.

Vigorous physical activity raises the heart rate to between 70% and 85% of the maximum heart rate. A 30-year-old person’s heart rate would be 133 to 162 if he or she was doing very vigorous activity.

How much time do you need doing aerobic activity?

The amount of aerobic activity recommended is 150 minutes a week of moderately-intense activity, or 75 minutes of vigorous-intensity aerobic activity, or an equivalent mix of the two. It is recommended to split this up over 3 or 4 days in a week. If you don’t have time to do, for example, 30 minutes of brisk walking all at one time on 5 days a week, you can break it up into 10 minute blocks. You can park farther away from your job and walk to work and back for 10 minutes at a time. You can walk in the morning and the evening, or perhaps fit some 10 minute sessions in at lunchtime.

You can exercise more than this to gain even greater health benefits. If you can do 300 minutes of moderate-intensity exercise a week or 150 minutes of vigorous aerobic exercise, you will be doing even more to improve your health in all the ways listed above. You can also split this time up between activities and into 10 minute increments if needed. In general, 1 minute of vigorous exercise counts as 2 minutes of moderate exercise.

But aerobic exercise is not enough. Strength training for your muscles is also important, and should be done at least two days a week. Most experts suggest doing strengthening exercises on days you do not do aerobic exercise, or if you are exercising a lot, using different muscle groups whenever possible.

You want to strengthen the muscles in your body core (abdomen, chest, and back), legs and hips, and shoulders and arms. You do this by repeating strengthening exercises to the point of fatigue. This means doing repetitive movements with each muscle group enough times and with enough weight that you cannot do any more.

Some strengthening exercises use just your body as weight, such as sit ups and pushups. Others require weights, like biceps curls. You can use your body’s weight against gravity, and you can use filled water bottles and later heavier things to lift. You may need to start with one pound weights if you have never trained with weights. There are also exercise bands that you can pull to exercise many different muscle groups. You do not need expensive equipment or a gym membership.

There are other activities that build muscle strength, including yoga and Pilates. You can do these in a group or follow directions from programs on DVDs. Heavy work around the house or backyard can also work muscles. You need to find things you can and will do. If group activities motivate you, there are frequently community-based classes that are inexpensive.

It is also important to add stretching after strength training as well as aerobic exercise.

There are many places to get information and watch videos on how to start exercising. If you are not sure you are healthy enough to exercise and haven’t recently, especially if you have any medical problems or are 50 years of age or older, check with your doctor first.

For more information:

There is information useful for everyone at this CDC site: http://www.cdc.gov/physicalactivity/everyone/getactive/index.html

2020 Topics & Objectives. Physical Activity. HealthyPeople.gov. http://www.healthypeople.gov/2020/topicsobjectives2020/overview.aspx?topicid=33

Other references

2008 Physical Activity Guidelines for Americans. At-A-Glance: A Fact Sheet for Professionals. October 2008. U.S. Department of Health and Human Services.

1 Comment

  1. All of my questions setkted-lhants!

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Dr. Anna Kaplan

Dr. Anna Kaplan graduated with a BA in English literature from Pomona College in 1975. She received her MD from U.S.C. School of Medicine in 1979. A three-year residency (training period) in family practice followed, and she was certified by the American Board of Family Physicians in 1982. She recertified, a normal procedure, in 1988 and 1995. She retired from active practice after 15 years, but keeps up with medicine via continuing medical education.

Dr. Kaplan has written in the medical field for both consumers as well as professionals. She has also authored hundreds of articles on other subjects.

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