Why Muscle Mass and Body Composition Are Key to Longevity and Health

Most of us know that exercise and diet are essential for a long and healthy life. But fewer people know how important it is to build muscle and maintain a good balance between muscle and body fat. Weight alone doesn’t tell the whole story. In fact, your body’s muscle-to-fat ratio, or body composition, is a critical part of functional health that affects energy levels, metabolic health, and resilience against illness as you age.

Here we look at why body composition and muscle mass matter for longevity, how muscle affects your metabolic health and energy, and what science-backed strategies can help you build muscle and maintain strength as you age.

What functional health is and why it matters for longevity

Functional health is all about optimising how your body works so you can live with energy and resilience over the long term. It takes a holistic approach, going beyond weight and calorie counting to consider factors like muscle mass, bone health, and metabolism. Functional health encourages proactive choices that strengthen the body, helping you resist common health issues like chronic inflammation, low energy levels, and age-related muscle loss.

Building a strong body composition is foundational to functional health. Research shows that muscle mass is directly tied to longevity. Adults over 65 with greater muscle mass had a lower risk of premature death, even after adjusting for factors like body fat percentage and cardiovascular risk factors. This suggests that a higher muscle-to-fat ratio is linked with better overall health and greater longevity.

As we age, maintaining a healthy ratio of muscle to fat becomes especially important. Not only does muscle play a major role in mobility and strength, but it also actively reduces inflammation, supports healthy blood sugar levels, and boosts metabolic health. This means that focusing on muscle mass and body composition can help you stay active, resilient, and energised well into your later years.

Why body composition and muscle mass are vital for health

Body composition refers to the ratio of lean mass (like muscle and bone) to fat in the body. Unlike weight, which is a single number, body composition provides a fuller picture of your health. Having a high muscle-to-fat ratio doesn’t just make you stronger-it also affects your metabolic health, energy levels, and immunity.

Muscle as a “secret weapon” for metabolic health

Muscle is not only important for strength but also plays a vital role in improving metabolic health. In fact, muscle tissue burns more calories than fat, even when you’re at rest. A study found that people with higher muscle mass have significantly higher resting energy expenditures, meaning they burn more calories throughout the day.

Additionally, muscle helps regulate blood sugar levels by taking up glucose from the bloodstream. This process keeps blood sugar steady, reducing the risk of developing insulin resistance, a major contributor to metabolic syndrome and type 2 diabetes. In short, more muscle means a more efficient metabolism and less chance of accumulating excess fat.

Muscle and inflammation: the anti-inflammatory benefits

Research shows that muscle can help reduce inflammation naturally. When we exercise, our muscles release molecules called myokines, which have anti-inflammatory effects. One study reported that these myokines help reduce systemic inflammation, potentially lowering the risk of chronic diseases like heart disease and certain cancers.

By maintaining a higher muscle mass, you help create a healthier internal environment, one that’s less prone to chronic inflammation. This makes muscle a powerful tool in managing inflammation and maintaining energy and resilience as you age.

Body composition vs. weight: the big picture

Traditional health metrics often focus on weight alone, but body composition gives a more complete understanding of health. Research found that people with higher muscle mass and lower fat mass had lower cardiovascular risk than those who were just “normal weight.” This highlights the importance of focusing on body composition vs. weight as a more accurate measure of health and longevity.

Instead of fixating on a number on the scale, focusing on muscle mass and fat percentage provides a clearer picture of your health. By improving muscle-to-fat ratio, you’re setting yourself up for better energy levels, reduced inflammation, and a longer, healthier life.

Methods for measuring body composition to track health gains

So how do you measure body composition accurately? There are various methods, from high-tech scans to simple at-home tools.

DEXA scan

The DEXA scan (dual-energy X-ray absorptiometry) is considered one of the most accurate methods for measuring body composition. It uses low-level X-rays to differentiate between bone mass, muscle mass, and body fat, giving you a comprehensive view of your health metrics. A study in Obesity found that DEXA scans were more accurate in detecting body composition changes than traditional scales, which don’t distinguish between muscle and fat.

DEXA scans are particularly helpful for tracking changes over time, especially if you’re actively working to build muscle or lose fat. While not available everywhere, they can be worth seeking out if you want a thorough analysis of your body composition.

Measuring tapes and body composition scales

If a DEXA scan isn’t an option, you can still get valuable insights with measuring tapes and body composition scales. Measuring key areas like the waist, hips, and arms with a tape measure can reveal changes in muscle and fat distribution over time. Body composition scales, which use bioelectrical impedance to estimate fat and muscle percentages, are another option, although they’re less precise than a DEXA scan.

Both of these methods are practical and affordable ways to monitor changes, helping you understand how your functional health is improving.

How muscle functions as a longevity and health indicator

Muscle plays a crucial role in the body, extending far beyond strength and movement. From supporting immune function to aiding in nutrient storage, muscle is an essential indicator of long-term health and longevity.

Muscle’s role in metabolic efficiency and inflammation reduction

Muscle is a highly metabolically active tissue, which means it requires more energy to maintain. This helps keep your metabolism running efficiently, making it easier to manage body weight and energy levels. As you build muscle, your body burns more calories, which is particularly beneficial for avoiding age-related weight gain.

Muscle is also involved in managing inflammation. When muscles are active, they release anti-inflammatory cytokines, which help counteract inflammation throughout the body. One study found that people with higher muscle mass had lower markers of inflammation, which supports the idea that muscle can help mitigate chronic inflammation over time.

Functional health: muscle as a “reservoir” for strength and nutrients

In functional health, muscle is viewed as a “reservoir” that stores nutrients and supports immune function, recovery, and metabolism. When we face stressors, illness, or injury, the body can draw on muscle reserves to help us heal and recover. This makes muscle not only a strength-building tissue but also a resource that supports resilience and longevity. In fact, one study found that older adults with more muscle mass were less likely to experience physical decline and hospitalisation, underscoring muscle’s role in healthy ageing.

Practical strategies to build muscle and support functional health

So, how can we build and maintain muscle effectively, especially as we age? Here are evidence-based strategies that are practical and achievable for all fitness levels.

Strength training

Strength training is one of the most effective ways to build and maintain muscle mass. Research shows that strength exercises like weightlifting, resistance band exercises, and bodyweight movements (such as squats and push-ups) are highly effective for increasing muscle size and strength. Strength training also improves bone density, reducing the risk of fractures and osteoporosis, which is a common concern as we age.

Start with two to three strength-training sessions per week, targeting large muscle groups like the legs, back, and chest. Even if you’re new to strength training, starting light and gradually progressing can yield significant benefits for functional health and longevity.

Optimising protein intake

Protein is essential for muscle maintenance and growth, especially as we age. Protein provides the amino acids needed for muscle repair and regeneration, and higher protein intake has been linked to better muscle strength and mass in older adults.

Studies recommend distributing protein intake evenly across meals to support muscle protein synthesis. Good sources of protein include:

• Lean meats: chicken, turkey
• Fish: especially fatty fish like salmon, which also reduces inflammation
• Eggs: a complete protein source
• Legumes: beans and lentils for plant-based protein
• Dairy: Greek yoghurt and cottage cheese for calcium and protein

Combining these proteins with anti-inflammatory foods like leafy greens, berries, and nuts can further support muscle recovery and reduce inflammation naturally.

Progressive overload

Progressive overload is a technique where you gradually increase the weight, reps, or intensity of your exercises to continuously challenge your muscles. This approach is proven to boost muscle growth and improve strength, making it a reliable strategy for building resilience and increasing energy levels over time.

For example, you might start by lifting 5kg weights and progress to 7kg as you get stronger. The key is to make small, incremental changes that keep muscles engaged without causing injury. Research highlights progressive overload as a highly effective way to sustain muscle gains and improve metabolic health.

Staying active throughout the day

Daily movement is essential for functional health and can support muscle maintenance even when you’re not at the gym. Activities like walking, gardening, and taking the stairs all contribute to a more active lifestyle. Research shows that even light physical activity can have positive effects on body composition, helping reduce inflammation and maintain a higher metabolic rate.

Prioritising recovery

Rest and recovery are as important as exercise when it comes to muscle health. Muscles need time to repair and grow after strength training, so prioritising recovery is essential. A study in Sleep found that adequate sleep supports muscle recovery and helps regulate inflammation, both of which are crucial for maintaining strength and energy as we age.

Aim for 7-8 hours of quality sleep each night and consider incorporating flexibility exercises like yoga or stretching to support muscle health and reduce stiffness.