The fitness world loves the debate: cardio or strength training? Which workout is best, and which can you cut from your exercise routine? The reality is cardio and strength don’t need to be mutually exclusive…
The fitness world loves the debate: cardio or strength training? Which workout is best, and which can you cut from your exercise routine? The reality is cardio and strength don’t need to be mutually exclusive — nor should they be.
“Both [cardio and strength training] need to be included in a well-rounded exercise program,” says Michael Rebold, certified strength and conditioning specialist and director of integrative exercise sciences at Hiram College in Ohio. That’s true whether you are vying for improved body composition, heart health or longevity.
“They complement each other,” says Dr. Daniel V. Vigil, a family medicine and sports medicine physician with UCLA Health in California. “Many of our acts of daily living rely on having efficient cardiorespiratory and musculoskeletal systems.” For example, walking the dog, playing with the kids or running to catch the bus rely predominantly on aerobic fitness, while getting up off of the floor, carrying groceries and performing home repairs rely more so on muscular fitness. Perhaps surprisingly, that’s also true of activity such as taking the stairs. Strength plays a bigger role than cardio in determining if you can make it up a flight of stairs without getting winded.
For most people, how much time you should devote to cardiovascular forms of exercise versus resistance training depends on what you enjoy most. “The best exercise, from a public health perspective, is the one that you actually like and will do,” Vigil says. That said, the right workout for you also depends on your individual health and fitness goals.
Below, experts share the unique benefits of cardiovascular exercise and strength training — and how to get the best of both workouts.
Muscle health. Your muscle cells, or fibers, exist in two main varieties: type 1 (also called slow-twitch or aerobic) and type 2 (known as fast-twitch or anaerobic), says Andrew R. Coggan, associate professor of kinesiology and integrative physiology at Indiana University Purdue University Indianapolis.
Low-intensity or sustained cardiovascular exercise (movements longer than a few minutes) primarily use the type 1 fibers, Coggan says. The fibers that are trained are the ones that adapt. They do so largely through increasing the size and number of mitochondria, the microscopic oxygen-using power plants within your muscle cells, as well as capillaries, small blood vessels that bring nutrients including oxygen to the body’s tissues, while removing carbon dioxide and other waste products, he says. These adaptations increase muscle endurance.
However, high-intensity, sprint-like cardiovascular exercise as well as strength training, especially at a high intensity, predominantly works type 2 muscle fibers, though such exercises also work type 1 fibers to a lesser extent. During a process called hypertrophy, muscle fibers adapt: The contractile units of each muscle cell grow and, eventually, the muscles as a whole are larger. As the contractile units grow, the muscle is better able to contract, resulting in greater strength and power, Rebold says.
Body fat levels. All exercise reduces body fat levels by expending energy. Cardiovascular exercise, especially low-intensity, steady-state exercise cardio, reduces body fat levels by expending calories. The largest determiner of how many calories you burn during a workout, regardless of exercise type, is intensity.
For example, in a 2013 Journal of Sports Science & Medicine study, exercisers who performed a 20-minute interval strength workout that included push-ups, burpees, squats and lunges expended an average of 15 calories per minute — nearly twice the caloric expenditure of a long run. The higher the exercise intensity, the more calories are burned during exercise. What’s more, more calories are burned after exercise as the body’s physiological systems recover. Known as excess post-exercise oxygen consumption, “it’s the icing on the cake,” Rebold says, noting that while high-intensity strength exercise is a small portion of overall caloric expenditure, it still matters.
However, strength training is unique in that it also influences fat loss by increasing muscle mass. Lean muscle boosts metabolic rate, enabling you burn more calories over the long term both during and after your workouts, he says. That explains why, in a 2015 Obesity study that followed 10,500 men for 12 years, Harvard researchers found that the men who performed resistance training gained less abdominal fat compared to those who spent the same amount of time each week performing traditional cardio workouts.
Cardiovascular health. With a name like cardiovascular exercise, it stands to reason that cardiovascular exercise would benefit heart health. And it does. However, it’s important to note that all exercise increases the workload on the heart and lungs and is therefore cardiovascular to some degree. While cardiovascular is the most common term, aerobic is the more scientifically accurate term for activities such as jogging and cycling.
“Both have been shown to be beneficial,” Vigil says. “Of the two, aerobic or cardiovascular training is more directly important than anaerobic or strength training, since it more effectively builds aerobic fitness [the body’s ability to deliver oxygen to tissues and use it].” In fact, a 2011 study published in The American Journal of Cardiology crowned aerobic exercise the most efficient form of exercise for improving cardiometabolic health.
Strength training — and the muscular adaptations that come with it — affects heart health more indirectly. By increasing muscle mass, it gives your cardiovascular system more places to store its blood, thereby reducing blood pressure on the arterial walls, explains Scott Collier, researcher and professor of cardiovascular exercise science at Appalachian State University in Boone, North Carolina.
By reducing levels of visceral fat, strength training also significantly lowers heart disease risk, Coggan says. In fact, regardless of overall body fat percentage, carrying excess visceral fat increases the risk of cardiovascular disease, according to a 2016 study published in the Journal of the American College of Cardiology. And a previous 2015 Lancet study IDed grip strength — a widely recognized surrogate for total-body muscle strength — as more accurately predicting the likelihood of death by heart disease than blood pressure.
Longevity. According to a 2014 Journal of the American College of Cardiology study, just 10 minutes of running per day at slow speeds significantly reduced risk of death from all causes. “When compared to one another, a person doing only cardiovascular training and no strength training would stand to improve longevity more than a person who only engages in strength training,” Vigil says.
“This would be ill-advised, however, since the two forms of exercise are complementary to one another,” he says. “This is especially true for the aging population who depend on adequate strength and balance to prevent falls and complications resulting from fall-related injuries.” According to the Centers for Disease Control and Prevention, falls are the leading cause of injury and death among adults age 65 and older.
However, recent research shows that maintaining muscle mass as you age, for which you need strength training, is a leading indicator of how long you will live and how healthy those years will be. A 2017 Current Opinion in Clinical Nutrition & Metabolic Care study found that lean muscle mass even outperforms body mass index at gauging overall health.