Moderate vs. vigorous exercise for cancer prevention

Exercise is an important part of cancer prevention and living a healthy life. It can help you obtain a healthy weight, lower your stress and strengthen your immune system. 

If you really want exercise to play a role in your own cancer prevention, you should aim for 150 minutes of moderate physical activity or 75 minutes of more vigorous physical activity each week.

But what is the difference between moderate and vigorous exercise? How do you know which one is right for you?

“The difference is the intensity,” says Whittney Thoman, a senior exercise physiologist in the Cancer Prevention Center. “Intensity is subjective. What can be vigorous for one person can be moderate for another and vice versa.”

Measuring activity level

So how can you tell the difference between vigorous and moderate activity for cancer prevention? There are three ways to tell the difference between these two types of exercise.

The rate of perceived exertion: The rate of perceived exertion is a simple and subjective test. Just rate the activity you’re doing on a scale from zero (not difficult) to 10 (extremely difficult). Consider how hard you're breathing, how much you're sweating and if your muscles are aching.

"Use zero for no activity at all,” Thoman says.  "Basically, it's how you feel sitting in a chair."

A moderate activity would be anything rated as a five to eight and a vigorous activity would be anything rated as a seven or above.

The heart rate test: Use a heart rate monitor to show how hard the exercise is working your heart. If the heart rate monitor says you’re working at 50 to 60% of your max heart rate, then the exercise is considered moderate. If the heart rate monitor shows that you’re working at 70 to 85% of your heart rate then it’s vigorous exercise.

To find your maximum heart rate, subtract your age from 220. For example, if you’re 45 years old, subtract 45 from 220 to get a maximum heart rate of 175. This is the maximum number of times your heart should beat per minute during exercise.

Keep in mind that some high blood pressure medications lower the maximum heart rate and target zone rate. If you’re taking one of these medications, talk to your doctor to find out if you need to use a lower target heart rate.

There are many different types of heart rate monitors, from straps to activity trackers to smart phone apps to those built in to treadmills and ellipticals. Thoman says it’s fine to use any of these heart rate monitors. Just make sure to use the same one to measure progress over time. Different heart rate monitors may show different results. 

The talk test: The talk test doesn’t require any additional equipment. To perform the talk test, see if you can talk or sing while performing the activity. If you’re doing a moderate exercise you should be able to talk, but not sing. If you’re doing a vigorous exercise, you shouldn’t be able to say more than a few words. 

Why vary activity level?

The average healthy adult should do a mix of moderate and vigorous forms of exercise to lower cancer risk, Thoman says.

“There are several benefits of doing exercises at a higher level of intensity,” she says. “Plus, it’s more time efficient because you can get a more powerful workout in quickly.”

Those benefits include:

• Improved cardiovascular health
• Increased metabolism
• Improved aerobic fitness

But moderate activity is important, too.

“It keeps you from burning out,” Thoman says. “We can’t all do vigorous exercise all the time.”

Vigorous exercise might not be right for everyone, especially patients with existing medical conditions. It’s best to talk to your doctor or an exercise specialist before starting a new exercise routine.

Request an appointment at MD Anderson's Lyda Hill Cancer Prevention Center online or call 877-632-6789.

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