Every day, as we age, our bodies go through changes. For adults who don’t stay active, there’s a risk of losing 3-8% of muscle mass every 10 years (1). This muscle loss can slow down metabolism, the process by which the body converts food, nutrients, and other substances (including chemicals and toxins) into energy, building blocks for cells, and waste products for elimination (2). When we eat, our body breaks food into smaller components to create energy and provide the building blocks needed for growth, repair, and overall health. A slower metabolism makes it easier to gain fat. The good news? There are steps you can take to keep your metabolism active and support a healthy weight! 

Metabolism can slow down for many reasons, including sedentary behavior, an imbalanced diet, dehydration, lack of sleep, stress, and insufficient muscle use. It’s also essential to rule out underlying health issues, such as thyroid disorders, hormonal imbalances, or medication side effects, which can further impact metabolic rate (3). 

One of the most effective tools we have to ignite metabolism, strengthen bones, increase longevity, boost brain function, improve balance, elevate self-esteem, reduce harmful visceral fat around organs, and enhance insulin sensitivity is strength training (4). By subjecting muscles to progressive overload through resistance exercises, we can achieve all these benefits. Strength or resistance training acts like a secret weapon. Our bodies are designed to adapt to physical stress, growing stronger in response to weight-bearing activities (5). This process breaks down muscle fibers, which then rebuild stronger during rest (particularly while sleeping) and when provided with necessary nutrients, such as protein and healthy carbohydrates (6). The body is constantly adjusting—getting stronger or weaker—based on the physical stress we place on it. 

Starting a new workout routine or going to the gym for the first time can feel intimidating. However, remember that resistance training isn’t just for athletes—it’s beneficial for everyone, regardless of age! 

Strength Training and Metabolism 

Strength training can help boost your metabolism because lean body mass (muscle) burns more calories at rest than fat (7). As we age, maintaining or increasing muscle through strength training can help combat the natural slowdown of metabolism. 

Studies show that increasing protein intake, even slightly, combined with resistance training (such as lifting weights), can help you gain muscle (8). This muscle gain enhances your metabolism, allowing you to burn more calories even when inactive. Additionally, having more muscle relative to fat is associated with better overall health and a reduced risk of metabolic-related diseases (9). 

Strength Training and Blood Sugar 

When you lift weights, your body becomes more efficient at using insulin, which helps maintain balanced blood sugar levels. This lowers the likelihood of developing Type 2 diabetes, and if you already have it, strength training can help improve your blood sugar levels (10). So, lifting weights isn’t just about building strength—it’s also about supporting healthy blood sugar management! 

Studies show that strength training can lower HbA1c levels, a key measure of long-term blood sugar control, in people with Type 2 diabetes (11-12). This improvement is often associated with muscle growth, as having more muscle helps your body use insulin more effectively. To maintain stable blood glucose levels, consider checking your blood sugar before and after exercise. Be mindful that exercise can cause your glucose levels to drop, and during intense workouts, they may temporarily rise. 

Strength training not only enhances the body’s ability to use insulin efficiently (reducing insulin resistance) but also allows any extra insulin in the bloodstream to support muscle growth and repair (4, 10-12). This dual benefit makes strength training a powerful tool for improving metabolic health and overall well-being. 

1. Strength Training and Insulin Resistance: Strength training can improve insulin sensitivity, meaning the body becomes more efficient at using insulin. When muscles are actively engaged, they can take up glucose (sugar) from the bloodstream with less reliance on insulin. This reduces the overall insulin load in the body, which is particularly beneficial for managing insulin resistance. In essence, strength training lowers the demand for insulin to regulate blood sugar levels, making the body more insulin sensitive. 
2. Insulin and Muscle Building: Extra insulin in the bloodstream can play a role in muscle building. Insulin is an anabolic hormone, meaning it facilitates the storage of nutrients like glucose and amino acids. These nutrients are essential for building muscle tissue and repairing damage caused by strength training. Elevated insulin levels after a meal or workout can enhance muscle growth by supporting protein synthesis and reducing protein breakdown in the muscles. This process helps the body recover and grow stronger after exercise. 

In summary, strength training improves the body’s ability to use insulin more efficiently (helping with insulin resistance) and enables the extra insulin in the bloodstream to support muscle growth and repair (25). 

Sending Health Your Way!

The Tula Clinical Team

Austin MS, RDN, CSR, LDN, CD
Aubree RN, BSN