How Bad Is It Really to Never Do Cardio?

There are people who absolutely love doing cardio every day... and those who don't. So if you're in the no-cardio camp, you might be wondering if your strength workouts are enough to keep your heart healthy and strong.

Current physical activity guidelines for adults recommend that you should get at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise each week. That amounts to about 30 minutes of moderate-intensity exercise or 15 minutes of vigorous-intensity exercise five days per week.

What that looks like exactly depends on the type of exercises you do. For example, some of the best cardio workouts include, walking, running, cycling and HIIT.

But if you're worried that doing cardio can get in the way of your goals of building muscle or bulking up, there's a way to work up a sweat without shrinking your muscles, says Merije Chukumerije, MD, a cardiologist at Cedars-Sinai Medical Center.

Try to do some low-intensity cardio at the start of your workout as part of your warm-up. This way, you're not completely gassed and still have energy left in the tank to lift heavy, he says.

So should you do cardio every day? And if so, you're probably wondering, how much cardio should I do a day? Deadlifters, this one's for you.

Don't get us wrong, there are plenty of benefits to hitting the squat rack often, and strength training should definitely be included in your workout routine. But avoiding aerobic exercise entirely can negatively affect your body — no matter your goals.

Case in point: An August 2012 study in ​BMC Public Health​ tested the effects of 12 weeks of resistance, aerobic or a combo of both in people with overweight and obesity. The goal was to determine the type of exercise that had the most cardiovascular benefits.

Researchers found that doing a combination of cardio and strength training provided the greatest benefits for weight loss and cardiorespiratory fitness, compared with aerobic or resistance training alone.

Plus, focusing solely on strength training can put you at risk for overuse injuries, especially if you're working the same muscle groups and joints every day. When you don't allow your muscles to properly recover, you actually inhibit them from repairing so that they can grow bigger and stronger.

By mixing up your workouts with low-intensity cardio, you can give your muscles a break and build your cardiovascular endurance. Cardiovascular endurance is important for improving your sports performance, which you're not able to ​optimally​ do if you're just lifting weights.

For example, if you're a runner and want to improve your mile time, spending more time on your feet is what's ultimately going to help you go the distance.

Only incorporating strength training in your routine can also affect your cardiovascular health, says Mike Nelson, PhD, MSME, CSCS, a certified sports and conditioning specialist.

If you only do strength training, it may become more difficult for your heart to pump blood because it thickens your heart's walls, Nelson explains. In the same way, doing only aerobic exercise can make your heart's walls too thin, so your heart can't contract properly to pump blood throughout the body.

Ideally, the best way to maintain healthy cardio health is to include both strength training and cardio exercises in your workout routine, Nelson says.

Now that you know what can happen if you skip cardio altogether, here's why it definitely deserves a place in your workout routine.

In addition to improving your heart's ability to pump blood and oxygen throughout your body, doing cardio regularly is associated with a lower risk of heart disease, according to Dr. Chukumerije.

"There are plenty of benefits related to cardiovascular disease, heart disease in general," Nelson says. "It potentially helps with high-density lipoprotein (HDL), so it can add some blood lipids. HDL can be increased with cardiovascular training."

Not all cholesterol is made equal: HDL is known as the "good' cholesterol because it helps get rid of other harmful types of cholesterol from your blood, according to Mayo Clinic, while low-density lipoprotein (LDL) is considered the "bad" cholesterol because it can clog up your blood vessels.

Higher levels of HDL are associated with a lower risk of heart disease and stroke, according to the Centers for Disease Control and Prevention (CDC).

A July 2017 systematic review in ​Lipids in Health and Disease​ analyzed the effects of aerobic exercise on lipids and lipoproteins. Researchers found that cardio exercise can increase HDL by 11 percent in sedentary adults. It may also lower LDL, though more research needs to be done to determine exactly how much it can.

Aerobic exercise and a healthy diet can help create a calorie deficit –– which is what happens when you burn more calories than you consume. Certain forms of cardio, like HIIT, can help you burn even more calories after a workout, thanks to the afterburn effect.

"It [cardio] also decreases adiposity — the amount of fat cells that are in the body," Dr. Chukumerije says.

In fact, a March 2013 study in ​Obesity Journal​ found that following a workout routine of aerobic exercise alone five days a week for people living with obesity resulted in significant weight loss.

Researchers also found that doing intense aerobic exercises was effective in reducing overall body fat in postmenopausal people, according to a September 2015 study in ​JAMA Oncology​. High-intensity cardio was proven to be more effective in decreasing adiposity than moderate-intensity cardio.

"Aerobic exercise decreases insulin resistance, a risk factor for type 2 diabetes," Dr. Chukumerije says. (FYI, insulin is the hormone that breaks down glucose for energy) Insulin resistance happens when your body rejects insulin, making the hormone less effective at getting glucose into your body's cells for energy, according to the American Diabetes Association (ADA).

But when your muscles contract during exercise, your cells are able to use glucose for energy, whether insulin is available or not, thus lowering your blood sugar levels, per the ADA.

You don't need to run for hours on the treadmill, either. Doing as little as 30 minutes of moderate-intensity cardio exercise for three to five days per week is associated with improved insulin sensitivity and glycemic control, according to a March 2017 study in ​BMJ Open Sport & Exercise Medicine.​

Keeping your blood sugar levels stabilized is important because it can help prevent or delay health problems like heart disease, kidney disease and vision loss, according to the CDC. Having stable blood sugar levels also allows you maintain a healthy weight and curb cravings for refined foods, per the Cleveland Clinic.

Hitting up the elliptical or treadmill a few days a week can also help prevent blood clots by decreasing blood viscosity (thickness), Dr. Chukmerjie says.

By reducing the thickness of your blood, you can lower your risk of blood clots that can clog up your arteries and veins, which can lead to a heart attack or stroke. That's because the thicker you blood is, the harder your heart has to work to move it around your body, according to Harvard Health.

Aerobic exercise works to increase plasma volume, and when plasma volume increases, blood viscosity decreases, per an April 2019 study in ​Oxidative Medicine and Cellular Longevity​.

Moreover, a small July 2015 study in ​Brazilian Journal of Medical and Biological Research​ examined the impact of high-intensity cardio exercise on blood viscosity and memory in older men. After following a six-month exercise program, participants in the experimental group showed a decrease in blood viscosity which may be related to the effect that aerobic exercise also has on the blood flow in the brain.

Cardio exercises can strengthen your heart so it can pump more blood with less effort, lowering your blood pressure, according to Mayo Clinic.

In a small July 2012 randomized controlled trial in ​Hypertension​, researchers observed the effect that cardio had on the reduction of blood pressure in people with resistant hypertension. It found that aerobic exercise lowered the blood pressure of participants who had low responsiveness to drug treatment.

There are many different types of cardio exercises, but the best kind is the one that you're going to do consistently. Nelson says the best cardio exercises are full-body movements that you're able to execute in a rhythmic pattern.

Do you have to do cardio every day? Not necessarily, but if you need some exercise inspiration, here are some of the most popular forms of aerobic exercise to consider adding to your routine.

There are many health benefits of running that makes it an ideal cardio exercise. It not only improves heart health but also promotes weight loss and helps boosts brain health.

If you're new to running, you can start out by alternating between jogging and walking, and as you build your endurance and strength, you progress to running for a longer distances and periods of time.

But if you're looking for something more low-impact than running, cycling is a great alternative. You'll get your heart rate pumping, increase your endurance and build strength in your lower body. Just make sure to gear up properly before your first ride, and choose roads with less traffic, so you can get into a steady rhythm with pedaling.

You can row indoors on a machine or outdoors on a boat. This low-impact, full-body workout targets many muscle groups, including your lower body (you use your legs to drive your stroke) and core. Consider using a rowing machine for 15 to 30 minutes a day for your cardio workout.

Dance is a feel-good way to get a great cardio workout; you're moving your entire body to the rhythm of the music, helping you work up a sweat and get your heart rate up.

There are plenty of beginner dance exercise videos you can do within a short period of time. "You can get a great workout if you put on a video and dance to it for 10 to 20 minutes," Dr. Chukumerije says.

The simple act of walking can help decrease stress and energize you, and the best part is you can tailor your walk to your fitness level. For example, you can walk continuously at the same pace for 15 to 20 minutes or you can mix in intervals of an easy stroll with power walking or jogging.

"So for one block, maybe walk at a ginger pace, but when you hit the stop sign and go for that next block, I want you power walking the whole rest of that block," Dr. Chukumerije says.

It's important to incorporate both cardio and strength training into your workout routine. Without some cardio exercise, you can raise your risk for heart disease. Plus, you miss out on other amazing cardio benefits, like stabilizing your blood sugar levels and lowering your blood pressure.

"It's not like if you never do cardio, but only do weight training, you're going to die early. We don't have data that says that," Dr. Chukumerije says. "But cardio should be a part of each workout even if it's to a small scale."

For example, if you like lifting weights, you can increase the amount of reps and decrease the weight. This allows you to lift at a faster pace and tax your heart so you get some aspect of cardio in your strength-training routine. You can turn your yoga flow into a cardio workout by transitioning from one pose to the next with fewer breaths in between. Or, you can tack a 5-minute HIIT workout onto the end of your strength session to get your heart pumping faster.

So should you do cardio every day? And if not, how often should you do cardio? And how much cardio should you do? The answer to these questions largely depends on your goals, such as building strength, changing your body composition, gaining endurance or just getting healthy overall, Nelson says.

If you want to lose 1 pound a week, for instance, you want to burn 500 to 1,000 calories a day, according to the Mayo Clinic. You can burn these calories by increasing your physical activity, by either doing traditional cardio workouts or non-exercise activities like gardening and cleaning. According to Harvard Health, a 155-pound person expends about 175 calories of energy after 30 minutes of walking at a fast pace, and with gardening, around 162 calories in the same amount of time.

For overall health, start with the current physical activity guidelines for adults: At least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise each week.

Strength-lovers, don't worry: You can still lift weights. Just pair your cardio with at least two total-body strength workouts per week.