For years, cardiovascular fitness was considered the epitome of what it meant to be healthy. Someone who could walk – or run – for miles was someone with a strong heart and lungs. That strong heart and lungs would help that person live a long and healthy life.
“The heart is the most important muscle of the body” is something that exercise and medical professionals have extolled for years—but what about all the other muscles in the body? Aren’t they important as well? That answer is a resounding YES, and it’s causing exercise and medical professionals to rethink their paradigm around cardiovascular fitness being the most critical indicator of human health and functioning.
Why the shift?
For decades, cardiovascular exercises were synonymous with heart health, increased fitness and fat loss. While it’s true that activities like running, cycling, and swimming are effective for burning calories and improving fitness, they aren’t the complete package. Enter strength training, which not only enhances muscle tone and strength but also delivers benefits strikingly similar to, if not better than, traditional cardio for some very critical aspects of health.
One of the most compelling reasons for the shift towards strength training is its profound impact on metabolism. Muscle is metabolically active tissue meaning more muscle mass leads to a higher resting metabolic rate. This means that even when you’re not working out, your body burns more calories at rest.
Cardio exercises might burn more calories during the workout, but strength training continues the calorie-burning process long after you’ve finished your last rep. This phenomenon, known as the “afterburn” effect or Excess Post-exercise Oxygen Consumption (EPOC), means your body continues to burn calories at an elevated rate following a strength training session.
Building Resilience and Bone Health
Bones lose their density because we load them less and less as we age. With bone mineral density (BMD), certainly hormone status plays a role, such as the loss of estrogen during menopause, as does dietary intake of things like calcium and Vitamin D (for the most part, higher levels are associated with better BMD). But the most significant effect of bone demineralization is lack of loading of the bones, which can lead to osteoporosis or its subclinical precursor osteopenia. We load our bones when we do impact-based activities, like walking and running, but also when we put stress, tension, and strain on the bones when lifting objects. This loading stimulates osteoblast activity in our bones. These are cells that literally lay down new bone. Less activity and less loading results in osteoclast activity, that breaks down bone, exceeding the osteoblast activity, with the net result being bone loss and reduced BMD.
Strength training is the ideal modality for loading bones, as it can place stress, tension, and strain on all the major bones of the body from different angles and positions, thereby maximizing BMD. If you think about how many ways you load the femur when walking, you’ll find it’s really one way. If you consider how many leg-based strength training exercises you can do to load the femur from different angles and positions, you’ll find you almost have too many to count. Bottom-line: to improve BMD and reduce the risk of osteoporotic fractures in the spine and hip, strength training is the most efficacious vehicle.
Functional Fitness and Mobility
The functional benefits of strength training are profound. Activities like squatting, lifting, and pushing aren’t just gym routines; they mimic real-life movements. By practicing these in a controlled environment, you’re better prepared for daily activities, whether it’s lifting grocery bags or playing with your kids. You develop better balance, coordination, and mobility, reducing the risk of injuries in everyday life.
On the other hand, while cardio is excellent for endurance, it doesn’t always translate to functional strength. Ever noticed that someone who can run a marathon might struggle with lifting heavy boxes? That’s the difference.
Heart Health and Metabolic Health
Here’s a fact that might surprise many: strength training is beneficial for cardiovascular health. A study from the Journal of Applied Physiology found that resistance training leads to better vascular function and reduced cardiovascular risk. Another study out of the International Journal of Environmental Research and Public Health showed that handgrip strength and muscle weakness are strongly associated with an increased risk of all-cause and premature mortality in healthy middle-aged and older adults. By improving heart health, strength training stands toe-to-toe with traditional cardio workouts.
Moreover, strength training aids in controlling blood sugar levels, making it an essential routine for people with type 2 diabetes. By aiding glucose transport to muscles, resistance exercises can play a pivotal role in managing and even preventing diabetes. While overall physical activity and exercise have proven very effective in reducing diabetes symptoms (see the DPP for more info on this), strength training plays a unique role. One of the big hallmarks of strength training is some level of increase in muscle mass.
Muscle is essentially the reservoir of carbohydrate in our body. Carbs either go to our muscles, our liver, or our fat cells when they need to be stored for energy use in the future. Liver carb stores are limited, and fat is clearly not an ideal place to store carbs. That leaves us with skeletal muscle as the best storage site for carbs. As we lose muscle (with age or disuse), we lose storage capacity. This can result in carbohydrates staying in the bloodstream longer, causing vascular injury, insulin resistance, and hyperglycemia.
The net effect of this is the diabetic cascade of events that increase cardiovascular disease as well as a slow death of our Pancreatic Beta Cells that produce insulin. Maintaining (or ideally increasing) muscle mass increases the gas tank for carbs in your body. This allows you to accommodate much more carbohydrate and reduce the likelihood of diabetes.
Putting it All Together
To optimize health, one must be physically active, get adequate sleep, and eat a well-balanced diet. Traditionally the physical activity category has largely focused on cardiovascular fitness and associated training modalities. While this emphasis is not incorrect, it fails to recognize the importance of strength training and muscular fitness on overall health. As we have seen in this article, there are many areas of health strength training will preferentially enhance over the improvement seen from traditional cardiovascular exercise. Clearly the ideal exercise program for health would include both aerobic exercise and resistance training. However, if you had to choose just one, the ever-increasing evidence continues to point towards resistance training.
Finally, for those interested in a more comprehensive review in the peer-reviewed literature, check out this article: The Benefits of Strength Training on Musculoskeletal System Health: Practical Applications for Interdisciplinary Care.