There’s a big source of confusion about “cardio” exercise that is negatively impacting many people who are trying get healthy.
The general public who wants to improve their heart health are often told to do “cardio”, which usually means riding a bike, plodding on the treadmill, hopping on a rower, taking an exercise class, going for a swim, or getting on an elliptical.
The notion that the above forms of exercise are a comprehensive list of cardio options held by most health care and fitness professionals. Over the last 2 decades of local and national lectures, I have asked well over 10,000 professionals and laymen what type of exercises are helpful for improving heart health. Every time, one of the above modes of exercises are suggested.
But what is concerning is what is almost never mentioned.
Rarely, if ever, is resistance training included as a type of cardio exercise.
This creates several problems.
First, it defies a litany of evidence showing how resistance training is very effective in improving cardiovascular function and reducing cardiovascular disease, including some evidence showing it is equally or more effective as aerobic exercise.
Second, it eliminates a mode of exercise that may be not only preferable, but also more efficient, modifiable, and accessible. This especially impacts those with comorbidities who need the benefits of exercise the most.
Finally, disregarding resistance training as a form of cardio reduces the likelihood that many will engage in the form of exercise that provides vast benefits affecting nearly every system and function of the human body, including the benefits that only resistance training can provide.
What follows is an overview of the evidence showing that resistance training does in fact improve cardiovascular function and reduces cardiovascular disease.
Furthermore, I’ll explore whether resistance training is actually better than aerobic exercise for improving cardiovascular health or whether some combination of the two types of exercise is preferable.
Resistance Training Improves Cardiorespiratory Function
Many studies have shown that resistance training increases cardiorespiratory function.
Peak oxygen uptake, stroke volume, and cardiac output are increased by resistance training. (Haennel, RG et al. Med Sci Sports Exerc. 1991)
VO2 max is a key indicator of cardiorespiratory function, increased by resistance training (Bryner RW et al J Am Coll Nutr. 1999)
Lung function in those with congenital heart disease is improved with resistance training. (Smith, Maia et al. European Journal of Preventive Cardiology 2018).
It’s important to note that this does not mean resistance training is better than aerobic training in improving cardiorespiratory performance. In fact, aerobic exercise like running and biking is likely more effective in improving such measures of cardiorespiratory performance. But acknowledging this does not mean that resistance training is not effective also, as the evidence clearly shows. However, when comparing resistance exercise to aerobic exercise in reducing cardiovascular disease, we see some interesting findings.
Resistance Training Reduces Cardiovascular Disease Risks
A Harvard study made headlines when it showed that those who were able to perform more than 40 pushups had a 96% lower risk of heart attack compared to those who were able to do 10 or less. (Yang J, Christophi CA, Farioli A, et al.. JAMA Netw Open. 2019). While this study shows an association, more robust studies show how resistance training as an intervention effects cardiovascular disease risk.
Several studies also show that resistance training reduces risk of stroke and heart attack. (Yanghui Liu, et al Med Sci Sports Exerc, 2019. Tanasecu, M, et. al. JAMA. 2002, Smith, M. American College of Cardiology Latin America Conference 2018, SHIROMA, ERIC J. et al.; Medicine & Science in Sports & Exercise: January 2017)
Similarly, a systematic review by Mann found several studies showing resistance training improved blood lipid profiles, especially when volume (sets and reps) is high. (Mann S, Beedie C, Jimenez A. Sports Med. 2014 )
McCleod and colleagues provide a thorough systematic review which consistently finds evidence demonstrating that resistance training reduces the risk of cardiovascular disease and mortality. (Mcleod JC, Stokes T, Phillips SM. Front Physiol. 2019)
A recent study revealed a potential mechanism of how resistance training can significantly reduce risk of heart failure. Patel et al tracked 5103 participants over 12 years who were overweight. 257 developed heart failure. Lowering their body fat and waist circumference significantly reduced risk of heart failure. Specifically, a 10% reduction caused a 22-24% lower risk of heart failure. (Patel, KV. et al. Circulation. Nov 2020) This would mean that an individual who was 200lbs and 30% body fat would need to lose 6lbs of fat to reduce their risk of heart failure by nearly 24%.
A notable finding, however, was that decreased muscle mass did not change risk of heart failure. This means that fat loss, not weight loss, is beneficial for lowering heart failure risk. Thus, preservation of lean mass is essential. Given the critical role resistance training plays in the preservation of lean mass, especially under conditions of calorie deficit and weight loss, we can infer that resistance training plays a critical role in reducing heart failure risks. (Patel, KV. et al. Circulation. Nov 2020)
Other studies show a similar correlation between muscle mass, strength, and cardiovascular disease. Both muscle mass and strength are independently associated with mortality and heart disease risk. (Srikanthan et al. Cardiol, 2016 Kim et al. Am J Clin Nutr, 2017). Ruiz and colleagues found that the best predictor of surviving from 70 to 80 in men was strength; the stronger they were, the less chance of mortality. (Ruiz et al. BMJ , 2008) Given the critical role resistance training plays in maintaining muscle mass and strength, it becomes more clear how resistance training can reduce cardiovascular disease.
Clearly, resistance training can significantly improve cardiovascular function and reduce cardiovascular disease. This is vital to acknowledge, because those who seek to improve heart health also seek other outcomes, such as reduce body fat, increase bone density, preserve muscle mass, increase strength, reduce fall risk, and improve function amongst many other benefits that resistance training is known to provide. By adding improved cardiovascular exercise to that list of benefits, people can be confident that they are simultaneously pursuing multiple critical health benefits with one type of exercise.
While the evidence does show that resistance training is effective for both improving cardiorespiratory performance and reducing cardiovascular disease, does this mean that resistance training is more effective than other types of exercise such as aerobic training?
Is Resistance Training More Effective Than Aerobic Training For Cardiovascular Health?
A couple of recent studies have found that resistance training was actually more effective than aerobic training for reducing cardiovascular disease risk.
Smith and colleagues found that engaging in resistance training was more significantly associated with decreased cardiovascular disease risk factors than those who were engaged in biking or walking. (Smith, Maia. Journal of the American College of Cardiology. 2019.)
In a more recent study, Smith also found that resistance training, even at very low doses, conferred cardioprotective benefits independent of the benefits experienced by those who were more active in other exercise. This means that those who were highly aerobically active, and added resistance training, had improved cardioprotective benefits compared to those that did not add resistance training. This study also showed that those who only engaged in resistance training had more cardioprotective benefits than those who only engaged in aerobic activity of greater duration. (Smith, Maia. Annals of Epidemiology. 2021).
Evidence suggests that resistance training is equal to or better than aerobic exercise in reducing blood pressure, a key metric associated with cardiovascular disease risk. Meta-analyses demonstrate that resistance training induces reductions in systolic and diastolic blood pressure that are of similar or greater magnitude to aerobic training in healthy adults (Cornelissen and Smart, J. Am. Heart Assoc 2013; MacDonald et al., Am. Heart Assoc 2016).
In fact, compared to individuals with normal blood pressure, individuals with hypertension yield the largest reductions in blood pressure following resistance training. (MacDonald et al., . Am. Heart Assoc 2016)
Given that most cite a lack of time as a major limiting factor towards participating in exercise, the following findings have very practical findings for increasing exercise compliance. A follow-up from the Health Professional’s Study, which included over 44,000 men, demonstrated that resistance for at least 30 min per week resulted in a similar risk reduction in fatal and nonfatal heart attacks compared to 2.5 h of brisk walking (Tanasescu et al., JAMA 2002).
This can be instrumental in making exercise seem less daunting, since 30 minutes of resistance exercise a week may provide similar cardioprotective effects as walking for a 5 times longer duration.
Liu and colleagues reported similar findings. Resistance training was found to provide cardiovascular disease risk reduction benefits that were independent from aerobic training. Notably, cardiovascular disease risk reduction of 40-70% was found in those who resistance trained less than 60 minutes a week. (Liu, Y. et al Med Sci Sports Exerc, 2019)
Other studies investigating mortality show a similar trend. Researchers from Australia showed those following only the resistance training guidelines based on the WHO recommendations had lower risk of death and cancer compared to those who followed the WHO health guidelines for aerobic activity. Specifically, engaging in resistance training 2 more times a week resulted in a 23% reduction in death and 34% reduction in cancer. Whereas those participating in 150 minutes of moderate to vigorous aerobic exercise a week has only a 12% decrease in death and no lower risk of cancer. (Stamatakis, e. Am J Epidemiology, 2017).
As mentioned earlier, Ruiz and colleagues found that strength was the primary factor that correlated with decreased risk of death from 70-80 years old in men (Ruiz et al.BMJ , 2008).
While these few studies are not enough to conclusively determine that resistance training is always more effective than aerobic exercise, there is convincing evidence to show it has profound effects and can likely provide them in less time. This can serve to not only elevate the role of resistance training in those seeking cardiovascular disease risk prevention, but it can improve its appeal as a time saving option which happens to provide multiple concurrent benefits, in addition to improving heart health.
But Is It Safe?
Why do so many, including medical professionals, fail to promote resistance training as a form of cardiovascular training, especially given the vast amount of supporting evidence?
Why the resistance to resistance training?
It’s likely that many are not aware of the research discussed here. But it can also be that there is some fear that resistance training is not safe for those with cardiovascular risk factors and conditions.
However, the evidence does not support such concern.
One research group investigated the risk of older adults with cardiovascular disease participating in low to moderate intensity resistance training. After pooling together data from 5 studies, they found that resistance training was associated with a lower rate of adverse cardiovascular complications than aerobic training. (Hollings et al. Eur. J. Prev. Cardiol. 2017).
Furthermore, a meta-analysis in older adults at risk for developing cardiovascular disease demonstrated that arterial stiffness (a correlate of cardiovascular mortality) does not increase or worsen following resistance training (Evans et al. Sports Med, 2018).
In fact, an acute bout of resistance training appears to be more protective from ischemic changes than a bout of aerobic exercise, and results in a lower heart rate response and higher diastolic perfusion pressure (Featherstone and Holly, Am. J. Cardiol 1993). These physiological changes result in a more favorable supply of oxygen to the heart during resistance training.
This evidence refutes the notion that resistance training is not safe for those with known cardiovascular disease risk.
Should We Only Do Resistance Training Exercise To Reduce Cardio Risks?
There is very little debate that aerobic exercise is beneficial for both reducing cardiovascular disease and for improving cardiovascular performance. There is compelling evidence that aerobic exercise is superior to resistance training for improving cardiorespiratory performance.
When it comes to cardiovascular disease risk reduction, as the evidence previously reviewed supports, resistance training has an independent effect on reducing disease, and that effect can be as strong or stronger than aerobic exercise. It has also proven to be safe, even in those with cardiovascular disease or known risk factors. Resistance training has also shown to provide cardiovascular benefits in substantially less time than aerobic exercise. But that doesn’t necessarily mean that you should forgo aerobic exercise, even if you are engaging in resistance training.
It seems that to have the greatest effect on reducing cardiovascular disease risk, it is best to include both aerobic and resistance exercise. Shiroma and colleagues found that women participating in both strength training and ≥120 minutes of aerobic activity had the largest cardiovascular rate reduction of 39% while women participating in aerobic training alone, or resistance training alone, experienced a reduction of 21-24% (Shiroma, E. J. et al.; Medicine & Science in Sports & Exercise: January 2017).
Stamatakis, et al showed that while those following only the resistance training WHO recommendations had lower risk of death (23%) compared to those who followed the aerobic activity guidelines (12%), those who followed both components of the guidelines had an even lower risk of mortality (29%). (Stamatakis, et al. Am J Epidemiology, 2017).
Given that aerobic exercise and resistance training both are effective and provided independent benefits for reducing cardiac disease, while appearing to have the greatest effects when they are combined, it is best to perform both resistance training and aerobic training to maximize cardiovascular disease and performance benefits.
However, doing both aerobic training and resistance training may not be feasible for multiple reasons. Some may not be able to tolerate the continuous, longer duration nature of aerobic exercise. In contrast, resistance training is intermittent in nature and infinitely modifiable in position and dosage to accommodate a wide variety of abilities and needs. Others may not have access to the space or equipment necessary for aerobic exercise. In contrast, resistance training can be performed in very limited spaces with little to no equipment (See my Ultimate Home Workout Manual here for examples). Furthermore, some may not enjoy long duration aerobic exercise and thus are unlikely to adhere to such recommendations.
Finally, many report that time is a substantial barrier to exercise (Justine M, et al. Singapore Med J. 2013. Daskapan, A. et al. J of Sports Sci & Med 2006). This is evident in the study by Stamatakis, et al showing that less than 19% of people are adhering to the WHO guidelines for physical activity. (Stamatakis, et al. Am J Epidemiology, 2017).
Thus, it’s important to know not only the most optimal exercise type, but also what the minimally effective dosage is, to reduce cardiovascular disease risk. In addition, pragmatic factors such as limited resources, abilities, and time are important considerations in determining what exercise mode is best.
The studies supporting the efficacy and efficiency of resistance training in relation to aerobic training are critical. They provide us with strong evidence to include resistance training as an excellent option that is highly modifiable with far reaching benefits to best select a proper exercise strategy to reduce cardiovascular disease risk.
To that end, based on the available evidence, in most situations this is how I would encourage people to prioritize their exercise and health pursuits to improve heart health, while also improving other aspects of health:
1. Do resistance training at least 2x/week
2. Modify diet, focusing on providing adequate protein, a high amount of fibrous foods, and a caloric amount to attain or maintain a healthy body fat percentage.
3. Engage in non-exercise activities daily/minimize prolonged sitting
4. Optimize sleep habits
5. Optimize stress management (therapy, meditation, social engagement)
6. Increase non-resistance training exercise (biking, elliptical, walking, running, etc.).
It’s hard to suggest that step 1 is more important than step 5, for example. But it’s clear that, when prioritizing which exercise to engage in, the evidence is suggesting that resistance training should take priority if one is not willing or able to do both.
If you need help with properly implementing an exercise program that is based on your unique needs, click here. We are always here to help.
A Clinical Example Why This Distinction Is Vital
Here’s a quick story that underscores why understanding that resistance training is actually cardio exercise is important.
It explains why I have such a problem with the false notion that cardio training is something that only happens on a treadmill or bike, and that resistance training somehow is not good for your heart.
A patient came to see me for help regarding a severe back problem.
One of the worst I’ve seen.
Fortunately, I knew I could help him and after a couple treatments there were noticeable improvements.
But he was extremely deconditioned. The muscle wasting from years of illness and inactivity was profound. He was going to need months of conditioning to reclaim adequate strength to support his spine and maintain the improvements he was getting from our therapy sessions.
Earlier in the year, he had a heart attack, and needed open heart surgery to clear the blockage.
He spent months and months going to “cardiac rehab”, which involved walking hunched over on a treadmill while holding the railings 3-5 x/week.
All the while his back pain was getting worse. After his cardiac rehab benefit was exhausted, his doctor thought it was finally time for him to have his back checked out by me.
His strength and mobility deficits were clearly contributing to his back pain, and PT treatment was required.
However, since he exhausted his insurance benefit because of his 5 months in cardiac rehab, he couldn’t get physical therapy treatment.
The treatment that would have improved his strength, pain, bone density, posture, fall risks, AND cardiac health was not allowed because of one thing:
The patient, cardiologist, and primary care practitioner wrongly believed, as so many others do, that cardiovascular training is limited to prolonged, sustained aerobic training on a machine.
If they were aware that resistance training is cardiovascular training, then he would have received the proper care that his insurance provides for.
This is not my opinion.
It is fact that cardiovascular function and performance are improved by resistance training.
It is a fact that risks of cardiac disease, including heart attack, are reduced by resistance training to a similar extent, and perhaps more so, than aerobic training.
If my patient received resistance training as part of his cardiac rehab, he would have been taking steps to concurrently increase muscle mass, improve bone density, improve strength, reduce fall risks, lower blood pressure, lower cholesterol, lower stress, lower risk of depression, improve cognitive performance, immune function, AND improve cardiac performance while lowering the risk of subsequent heart attack, stroke, diabetes, and death! All the while, it would have addressed the underlying impairments related to his back pain.
He would undoubtedly been healthier and in less pain by now. It would have cost less too.
This is the consequence of adhering to narrow and poorly defined categories of exercise.
Hopefully the message is getting clearer for you: if you want to have a healthy heart, make resistance training a priority in your plan. When you are super busy and overwhelmed, trying to figure out where to start, or what is the least you can do to get the biggest benefit, start with resistance training.
At the very least, if you don’t enjoy running, sitting on a stationary bike, or plodding along on an elliptical, you can be assured that by doing strength training, you are still working on improving your cardiac health.
If you want to incorporate resistance training into your routine but don’t know where to start, we are always here to help.