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Internal Medicine

How Much Exercise Do I Actually Need?

A sedentary lifestyle can lead to serious health risks, comparable to smoking. Regular exercise is key to preventing issues like obesity, heart disease, and premature death. Learn how much activity you really need to stay healthy.

Lena Rydberg Freese


woman walking with water bottle

"Sitting is the new smoking.”

You’ve probably heard the phrase a lot since the United States Health and Human Services (HHS) first released its Physical Activity Guidelines for Americans in 2008. There’s a lot of truth to it.

Smoking was a concerning public health crisis when the health community raised awareness of the danger and disease caused by cigarettes. More and more evidence today suggests a sedentary lifestyle has similar effects. But the prescription for prevention is simple: get up and get moving.

What are the health risks of a sedentary lifestyle?

When you’re living a sedentary lifestyle, that means you’re getting little to no physical activity. And exercise is one of the best things for your health. Without regular activity, your body can’t function as well as it needs to. You end up:

  • Burning fewer calories
  • Losing strength and endurance
  • Weakening your bones and immune system
  • Developing inflammation, poor circulation and poor metabolism

All that damage to your body has major consequences. The effects of being sedentary put you at a much higher risk of chronic conditions:

  • Obesity – Burning fewer calories makes you more likely to gain weight.
  • Heart problems – Your heart needs exercise just like any other muscle to stave off heart disease, heart attack or high blood pressure.
  • Type 2 diabetes – Exercising less than three times a week increases your risk of diabetes.
  • Cancer – Certain cancers like breast, uterine and colon cancers are associated with a sedentary lifestyle.
  • Osteoporosis – Weakened bones and mineral loss make your bones more likely to break and you more likely to fall.
  • Mental health issues – Regular exercise is a natural mood booster that is proven to reduce symptoms of depression and anxiety.
  • Premature death – Due to these chronic conditions and other factors, a sedentary lifestyle also increases your chances of dying earlier.

How much exercise is recommended to live a healthy, active lifestyle?

The Physical Activity Guidelines for Americans have been out for more than a decade, and public health campaigns to get moving are everywhere. Yet, a new study in the Journal of the American Medical Association found that our hours of sedentary time have actually increased over the last 10 years.

But the recommended amount of exercise to counteract the effects of sedentary behaviors is not that much. Really!

“A lot of people think they need to work out in a gym for 90 minutes a day, five days a week, in order to get any sort of benefit. Really, the dose is a heck of a lot less than that,” says Lena Rydberg, DO, an Internal Medicine physician at The Iowa Clinic in West Des Moines.

The exercise guidelines are not one-size-fits-all either. HHS has specific, science-based recommendations for toddlers, children and teens, adults, older adults, pregnant women and people suffering from chronic disease or disability.

Recommended Physical Activity for Adults

“The activity guidelines have changed recently,” Dr. Rydberg says. “The dose for what you need for cardiovascular benefit is 150 minutes per week at a heart rate greater than 100.”

Further, the 2nd edition of Physical Activity Guidelines for Americans, released in 2018, recommends:

  • Aerobic physical activity – For substantial health benefits, you need at least two-and-a-half hours at moderate intensity or 75 minutes at a high intensity each week. That’s as little as 22 minutes a day of exercise. But it’s recommended you aim higher and get twice that — five hours a week (43 minutes a day) of aerobic activity.
  • Muscle strengthening – You have to do more than get your heart rate up. Additionally, you need to work all major muscle groups at least two days a week at moderate intensity or higher.
  • Exercise at least three days a week – It’s easier to fit exercise into your schedule when you have more time on the weekends. But research consistently shows a greater benefit when you spread out your exercise over at least three days of the week.

Exercise Guidelines for Children

Environment plays a major role in the health of children, and it starts as soon as they’re up and moving. Encourage play and physical activity in your kids to establish healthy habits and prevent childhood obesity.

For toddlers between the ages of three and five, that’s also important to their growth and development. For older children and adolescents, the recommended amount of exercise per week is actually more rigorous than adults. Kids between the ages of six and 17 need an hour of physical activity every single day, with that time divided into three areas:

  • Aerobic physical activity – Most of the hour should be spent in cardiovascular activities. At least three days a week should include vigorous-intensity activities.
  • Muscle strengthening – This should also be a focus on at least three days a week so children develop strong, healthy muscles.
  • Bone strengthening – Activities that put pressure on the bones promote bone growth and strength. So anything that requires running and jumping or includes a force impact with the ground should be done at least three days a week. Bone-strengthening activities often overlap with the other two areas of exercise.

Not all of this exercise has to come at home. Physical education, recess, sports and after-school activities help kids stay active on school days. Add up their active time at school and supplement with a fun physical activity at the end of the day. On the weekends, set aside some time for a family walk, bike ride or other physical activity everyone can enjoy.

How much exercise does it take to lose weight?

Nearly two-thirds of Iowans are overweight or obese, according to data from the Centers for Disease Control and Prevention. And many of the remaining 35 percent of Iowa residents have their own concerns about maintaining a healthy weight.

If weight loss is a goal, you have to go above and beyond the 150-minute recommendation, Dr. Rydberg says.

“A lot of people think, ‘Oh, I’m going to lose all this weight with activity.’ But you don’t. You get a great cardiovascular benefit,” Dr. Rydberg says. “Weight loss takes different work. You can expend all this energy in an area that’s really not making a difference.”

Studies show that the most physical and mental health benefits are achieved by people who exercise at the upper end of the physical activity guidelines. This is especially important if you’re trying to lose weight. Diet also plays a major role in weight loss. But the more you work out, the more calories you burn and pounds you shed.

“For weight loss, that needs to be 300 to 450 minutes with your heart rate at 100 — half of that if it’s higher than that,” Dr. Rydberg advises. “So for that, you might need to go to the gym more. But there are still plenty of other everyday activities that will help get you there.”

What kind of activities do I need for physical fitness?

The guidelines are pretty simple. Move more, sit less. Because some physical activity is better than none at all.

Keeping track of your minutes is a lot easier too. Fitness wearables, smartwatches and smartphones all can help you track your activity levels to take the burden off of you.

“Most of the FitBits and other activity trackers monitor your heart rate and track active minutes. You can sum up your minutes per week from that,” Dr. Rydberg says. “You may be getting enough exercise with a lot of everyday activities like walking, gardening and doing all the things you enjoy. You don’t have to get your physical activity all in the gym if you’re getting it other places.”

But if you have no easy way of tracking your heart, it can be hard to know what qualifies as moderate or vigorous physical activity. So instead, think of in terms of how much energy or effort you have to expend to do an activity.

Moderate physical activity would be a five or six on the intensity scale. Your heart beats faster and you’re breathing heavier but you could still talk and exercise at the same time. Vigorous activity would be a seven or eight. Your body feels warmer, you start to sweat and you can’t possibly talk without running out of breath.

Types of Moderate and Vigorous Physical Activity

Moderate-Intensity Activities

  • Brisk walking (2.5 mph pace)
  • Swimming for fun
  • Riding a bike (<10 mph pace on flat ground)
  • Vinyasa or power yoga
  • Yard work and gardening
  • Home repairs
  • Heavy cleaning (mopping, vacuuming, etc.)
  • Aerobic exercise classes

Vigorous-Intensity Activities

  • Jogging or running
  • Lap swimming
  • Cycling (faster than 10 mph and on hills)
  • Jumping rope
  • Heavy yard work (digging, shoveling, etc.)
  • Hiking (Uphill with a heavy backpack)
  • Active sports (basketball, tennis, soccer, etc.)
  • High-intensity exercise classes

The most important recommendation for exercise is to do what works for you. You’re more likely to stay active if you enjoy the activities you pursue. Instead of dreading a workout, you’ll look forward to a favorite hobby. And if you’re having trouble getting started, sticking to a routine or hitting your weight loss goals, your primary care provider can help you switch to a healthier, more active lifestyle.

Lena Rydberg Freese

LenaRydberg Freese , DO

Lena Rydberg, DO is board certified in Internal Medicine and a member of the American Medical Association and American College of Physicians. Prior to joining The Iowa Clinic. Dr. Rydberg practiced medicine in Tucson, Arizona.

Dr. Rydberg believes communication is one of the most important aspects of medicine. She chose Internal Medicine because she enjoys building the close relationships that are found in Primary Care and she has always had a special interest in adult medicine. Outside of the clinic, Dr. Rydberg is an avid reader and enjoys hiking with her husband and children.