Exactly What Cardio Does for Your Body, Explained

Cardio Workouts

Getty/Design by Cristina Cianci

Everyone knows cardiovascular activity is “good” for you, but that doesn’t mean everyone loves it. Cardio requires a lot of effort, your heart races; you get out of breath, etc. Working out your heart is a good thing, though, and cardio does that—and so much more. We talked to two experts to find out why you should still be including cardio in your workout routine, what it does for your overall health, and how often you should do it. 

Meet the Expert

Why Is Cardio Important?

When it comes to workouts, cardio vs. strength training is not necessarily an either/or situation. Strength training is great for building muscle, but it does not improve cardiovascular health as aerobic exercise does, says Leann Poston M.D., M.B.A., M.Ed. She says it’s important to vary your workouts as much as possible, so a combination of both is ideal.

“I always recommend training with both cardio and strength,” says Selena Samuela, a Peloton trainer. “If you are someone who doesn't have a lot of time or someone who maybe just doesn’t love working out and you want to pack it all in, try a bootcamp style class.” (She swears by the Peloton Tread Bootcamps as ways to get an equal amount of cardio and strength in one super-efficient workout).

Bonus: Cardio workouts can help your strength workouts and vice versa. Increasing your cardiovascular ability will help everything and anything you do, says Samuela, and strength training will help your cardio workouts by improving your neuromuscular coordination and power. It also helps you avoid injury by strengthening your muscles. 

What Are the Benefits of Cardio?

Cardio is good for both your heart and your head. Here are a few of the benefits. 

  • It improves cardiovascular health. We know that cardio is good for your heart, but what does that mean exactly? Cardio workouts increase your heart rate and respiratory rate, says Poston. As you strengthen your heart, you may lower your blood pressure, reducing the risk of cardiovascular disease.
  • It burns calories. The continued effort during a round of cardio means you’re continuously burning while you’re doing it. For example, according to the CDC, on average, a 154-pound person burns 110 calories during 30 minutes of weightlifting but burns 230 calories during 30 minutes of walking or 295 calories in 30 minutes of jogging.
  • It can help prevent diseases. Cardio can prevent obesity and insulin intolerance, which lead to type 2 diabetes, says Poston. Aerobic exercise also increases blood flow, including to your brain, which can improve alertness and decrease the risk of stroke and declines in brain function with aging.
  • It can boost your mood. When you feel great after a workout, it’s because you’re releasing endorphins, says Samuela. One JAMA Psychiatry study showed that exercise could reduce the risk of depression. Another study in the British Journal of Sports Medicine showed that aerobic exercise could reduce the severity of symptoms in depressed patients.
  • It can be a stress buster. If, after a long day, you find yourself needing to go out for a walk or a run, it could be because cardio can help you de-stress. An Academic Press article showed that aerobic exercise could counter the adverse effects of stress. At the same time, a study in Frontiers in Physiology found that regular exercises are more resistant to acute stress's emotional effects (i.e., daily stress).
  • It can strengthen your bones. Bone strength becomes increasingly important as we get older, and according to the NIH, both strength-training and weight-bearing exercises (walking, jogging, even dancing) can strengthen your bones.
  • It can help you sleep better. Doing cardio may help with sleep. According to a Northwestern University study of middle-aged to older adults with insomnia, aerobic exercise helped Improve both the quality and quantity of sleep.

How Much Cardio Should You Do A Week?

The amount of cardio you do a week is a personal choice, but Samuela suggests aiming for at least two hours' worth of cardio spread throughout the week. But if you’re doing more rigorous exercise like HIIT workouts, she adds, that number could look different (e.g., you might need less).


For other guidelines, Poston cites the American Heart Association, which recommends at least 150 minutes of moderate-intensity cardio or 75 minutes of vigorous-intensity cardio workouts (or a combination of both) spread over the week.

However, it is possible to have too much of a good thing. Poston says you can get overuse injuries and get fatigued to the point where your risk of falls or injury increases. Besides the exercise's length, she recommends making sure you stay below your maximum recommended heart rate, which is about 220 minus your age, and watch out for persistent muscle and joint pains, the inability to sleep, or increased infections. All in all, listen to your own body. 

 How to Choose The Right Cardio for You

Samuela has a message for anyone who says they can’t stand running. “I think folks who say ‘I hate running’ don’t have an injury keeping them from running, but are folks who probably have been scarred by trying to do too much too fast and not being kind to themselves.” Instead, she recommends walks and runs to get started and to ease into it. But she says there are also tons of other ways to get cardio in if you can’t or don’t want to run, including cycling, swimming, rowing, or doing HIIT floor exercises. Find something you enjoy and stick to, and that’s the right cardio for you.

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