The amount of muscle on your body matters—for everyone. Whether you’re an athlete, on a weight loss journey, or enjoying your 8th decade of life (or more!), having adequate muscle is important for your health. Read on for details about what muscle does in the body, and how you can help preserve your precious muscle.
What Muscles Do
When someone says the word “muscle,” most of us think of things like our biceps. You know, the muscles we can easily see working for us. But many of the roughly 600 muscles we have in our bodies are hard to see. And the work they do is largely invisible to us. The majority of our muscles are skeletal muscles. They allow us to make voluntary movements like exercising, cooking, or turning the pages of a book. The other two categories of muscle are cardiac muscles and smooth muscles. These muscles perform involuntary movements that are controlled by the nervous system, like pumping blood and eliminating waste. The work of the muscles also impacts a number of body systems, including the respiratory, urinary, digestive, and reproductive systems. And this isn’t all that muscles do for us.
Muscle and Metabolism
One of muscle’s most important roles is its contribution to metabolism. All muscle is metabolically active tissue, meaning it requires energy in the form of calories from the food we eat. The more muscle mass you have, the more calories you burn, even while at rest (that’s your resting metabolic rate). Conversely, losing muscle—especially with age—can lower energy expenditure. Over time, this shift may make it easier to gain weight—even if dietary intake remains the same.
How Muscle Helps Regulate Blood Sugar
When we eat, insulin releases in response to the normal increase in circulating blood glucose (from the breakdown of food). Skeletal muscle is essential for glucose regulation, since it’s responsible for clearing 80% of post-meal glucose. When muscle mass reduces, this process becomes less efficient, which may contribute to insulin resistance over time. Maintaining muscle mass can help improve insulin sensitivity and support blood sugar control. It’s an important strategy for addressing pre-diabetes and managing type 2 diabetes as well.
The Link Between Muscle and Longevity
Muscle is a key contributor to long-term health outcomes and longevity. Research on the exact mechanisms involved is ongoing. But there are several aspects of muscle functions that likely support its role in helping us live better, for longer. One is that muscle mass and strength help people stay active. This allows them to enjoy the benefits of exercise, such as increased cardio fitness and endurance, greater mobility, and less risk of injury (more on that below). During periods of illness or physical stress, muscle also serves as a storage site for amino acids, which help us with recovery.
Muscle Improves Functional Fitness and Injury Prevention
Muscle is essential for maintaining the ability to perform everyday tasks. Standing up from a chair, climbing stairs, carrying groceries, or lifting a child or grandchild. All of these activities rely on adequate muscle strength. Unfortunately, starting at midlife, our muscle mass and strength naturally begin to decrease. And it picks up dramatically around age 65 or so, when sarcopenia becomes more noticeable. Sarcopenia is associated with increased risk of falls, osteoporosis, and frailty. Doing our best to preserve the muscle we have is important for maintaining mobility, stability, and overall quality of life.
How to Preserve Your Muscle
It doesn’t require major lifestyle changes or extreme amounts of exercise to support muscle maintenance. In fact, research consistently points to two primary strategies: adequate protein intake and regular resistance-based activity—two things we talk about regularly in this blog. Just doing one of these things and not the other, however, can limit your progress. Plan to take steps toward both strategies for true muscle support. In addition, staying hydrated helps your muscles function at their best, so don’t forget to drink plenty of water. (Click here to see how Guiding Stars can point you to some healthy beverage choices.)
Prioritize Protein. Protein provides the amino acids needed to repair and maintain muscle, and of course, to build more muscle. However, protein isn’t a one-size-fits-all thing. The amount you need depends on several factors, including your age, gender, weight, activity level, health status, and medications. General recommendations range from 0.8–1.2g/kg body weight/day for most adults, often on the higher end (1.2g/kg) for older adults. Regular exercisers may benefit from even higher amounts, up to around 1.5g/kg body weight or more, depending on the type of activity, intensity, and frequency.
Keep in mind that weight loss can negatively impact muscle mass. Consult with your physician or a Registered Dietitian about your protein needs if you are trying to manage your weight or taking a GLP-1 agonist medication. Other recommendations: Distribute your protein intake across your meals (aim for 20-30g per meal). And don’t get stuck on just one type of protein—enjoy both plant-based and animal sources.
Include Resistance Training. Resistance training stimulates muscle protein synthesis and helps maintain (or increase) muscle mass and strength over time. No gym membership is needed and you don’t need a lot of equipment. You can perform resistance exercises using your own body weight, or with a few hand weights or an exercise band. Moderate resistance training 2-3 times a week is often sufficient, and it’s never too late to start!