Your Guide to Adding Muscle Mass

Key takeaways:

• Muscle is a metabolically active organ that influences bone health, heart function, insulin sensitivity, immunity, and brain health—not just movement and strength.
• Progressive overload is key—your muscles need to be challenged through increasing difficulty over time to grow effectively.
• Focus on compound movements like squats, deadlifts, and presses, which engage multiple muscle groups at once.
• Start with 2 sessions per week, ideally under the guidance of a trainer, and prioritize proper form.
• Adequate protein and calories are essential: Aim for 0.7-0.8g protein per pound of body weight daily, spaced throughout the day, while eating at maintenance calories or above.

Though we may think of muscle mass as something to benefit athletic performance—or aesthetics—it’s actually a key component of healthy longevity. Without adequate muscle mass, we expose nearly all of our body systems to impairment, particularly as we age.

Muscle mass begins to decline gradually around age 30 and again around 50-60, muscle mass decreases more rapidly. If we don’t actively work our muscles, the rate of muscle loss can increase further. "After 30, we can lose up to 1% of muscle mass per year,” says Atria exercise physiologist Will Sands, who has designed and implemented performance training programs for professional athletes. "In terms of actual strength, we can lose up to 2% a year, which compounded year after year starts to add up."

There is a common misconception that metabolism slows around age 30; in fact, research shows it's stable until closer to age 60. The perceived slowdown is often due to the loss of muscle mass, not inherent metabolic changes, since muscles burn more calories both at rest and during exercise. In other words, maintaining muscle mass as you age can actually prevent the experience of a slowed metabolism.

If adding muscle mass is a priority for you—and especially if you are on a GLP-1 medication, which can increase muscle loss—it can be helpful to understand how vast the health benefits can be.

The importance of muscle mass for broader health

Muscle tissue isn't just about movement and strength—it's a metabolically active organ that influences virtually every system in your body.

Bone health

• Bone density: Muscle contractions create mechanical stress on bones, stimulating bone formation. This helps prevent osteoporosis and reduces fracture risk, so it’s particularly important as we age.
• Joint stability: Strong muscles act as dynamic stabilizers around joints, reducing wear and tear on cartilage and ligaments. Well-developed muscles also maintain proper spinal alignment and posture, reducing chronic pain and movement dysfunctions.

Heart health

• Blood pressure: Having more muscle can help keep your blood pressure in a healthy range, partly because it improves how your body handles insulin and supports better blood flow.
• Reduced cardiovascular disease risk: Higher muscle mass correlates with lower rates of heart disease, stroke, and deaths caused by heart disease.

Metabolic health

• Insulin sensitivity: Muscle is where most sugar from your blood gets used. Having more muscle helps your body respond better to insulin and keep blood sugar levels steady, which lowers the risk of diabetes.
• Increased metabolic rate: Muscle tissue burns more calories at rest than fat tissue.
• Improved fat oxidation: Well-developed muscles are more efficient at burning fat for fuel, both during exercise and at rest.

Immunity

• Enhanced immune function: Regular resistance training and having enough muscle helps keep your immune system strong and better able to fight off illness.
• Reduced chronic inflammation: Muscle tissue produces anti-inflammatory chemicals called myokines, which help combat chronic low-grade inflammation linked to numerous diseases.

Brain health

• Cognitive function: Exercise that builds muscle increases production of something called brain-derived neurotrophic factor (BDNF), which can literally increase brain volume, support cognitive health, and potentially reduce dementia risk.
• Mood: Lifting weights and building muscle can help your brain make more of the chemicals that control mood, which may ease depression and anxiety.
• Neuroprotection: Those same myokines that can reduce chronic inflammation may also help protect against neurodegenerative diseases.
• Neuromuscular coordination: Maintaining muscle mass preserves the neural pathways that control movement, balance, and coordination.

The science behind muscle growth

At the cellular level, muscle is created through the mTOR (mechanistic Target of Rapamycin) pathway, which regulates how cells grow and multiply, among other processes. The mTOR complex is activated by things like dietary protein and exercise.

"We have to have what’s called ‘mechanical tension’ in order to build muscle mass," says Sands. "And in order to get mechanical tension, we need some load placed on the body."

We have two types of muscle fibers. Slow-twitch fibers are good for endurance; they contract slowly and resist fatigue. They’re primarily what gets used in distance running, for example, and maintaining good posture. Fast-twitch fibers contract rapidly and forcefully when you move but fatigue quickly (these are the ones you work when you do something like high-intensity interval training, or HIIT). They dominate explosive movements like sprinting, jumping, and heavy lifting.

To add muscle mass and improve strength, it’s important to build up more of these fast-twitch fibers in particular. The key to this is progressive overload—challenging your muscles progressively—whether through heavier weights, more reps, harder variations, or increased time under tension. Weight lifting is just one (very effective) method.

Strength training

While many forms of exercise may count as resistance training, not all will help with building muscle mass.

“Yoga and Pilates are good for stability, balance, mobility, and flexibility, and they target core strength and small muscle groups” says Sands. “But if we're talking about strength and force production, the only way to get that is through mechanical tension from resistance training.”

Body weight training can be a good place to start, but eventually, you will have to add more weight to see results. Some kind of weight training is key, whether that is through free weights or machines.

Before adding significant weight, focus on your form. “There’s a brain-to-muscle connection—we need a strong signal from our nervous system to activate muscles,” says Sands. “It’s important to learn the basics: how to push and pull with your upper body, and how to squat and bend at the hips correctly.”

It can be helpful to recruit a personal trainer when starting out. "My first choice is going with a professional," says Sands. "That way it's supervised and progressive. Progressive overload is one of the biggest principles of adding muscle, and a professional can identify when you’re ready to advance to the next level."

Whether or not you work with a trainer, you’ll want to aim for compound movements such as:

• Squats
• Romanian deadlifts
• Dumbbell chest presses
• Cable rows

Machines offer advantages for beginners because "there's less teaching involved, and you can get a good stimulus of mechanical tension," says Sands. This may include:

• Machine leg extensions
• Machine leg presses
• Machine leg curls

If joining a gym or working with a personal trainer doesn’t align with your life right now, we recommend apps such as the Nike Training Coach app or Equinox+. It can also be helpful to do a limited series with a trainer, such as two or three sessions, to ensure proper form and understand when it’s time to up the ante on your training.

Two days of strength training per week is a good starting point. Over time, you can build up, aiming for 5 to 15 sets per muscle group weekly. It’s a good idea to leave 48 hours between sessions to allow for adequate recovery. You’ll start to notice increases in muscle mass after about 6-8 weeks of consistent strength training.

Other considerations

GLP-1 medications

Anyone on weight-loss medications needs to think seriously about muscle preservation. "When someone's on a GLP-1, a significant amount of tissue loss may come from muscle if we're not doing something to push up against that," warns Sands. Since GLP-1s often aid in calorie restriction, resistance training and adequate protein intake become even more important.

Age and gender

Older adults can still build muscle effectively, and while men may see quicker or larger absolute gains, women can still achieve substantial relative increases in muscle mass and strength, says Sands. Focusing on strength training as you age is a key component of injury prevention and disease resistance.

Sleep

“In order to build muscle mass we need to have both a stimulus and a response,” says Sands. “That response typically happens in our sleep, which is why it’s important to get optimal sleep” for muscle repair and generation.

Optimal Nutrition for Muscle Mass Gains

Nutrition is equally important as training. "What's going to increase muscle mass the most is a combination of resistance training and adequate protein," explains Atria dietitian Adam Ross, recommending about 0.7 to 0.8 grams per pound of body weight daily.

The importance of protein and calorie intake

Proteins and the amino acids that form them are related to the structure of everything in our bodies, from the brain to our hormones to, yes, muscle. That means our muscles are competing with a lot of other body systems for sufficient protein. “If you’re on a low-calorie diet,” says Atria dietitian Adam Ross, “the body will use protein for essential functions before using it to build muscle.” That means anyone looking to add muscle mass needs to eat more than the recommended daily amount (RDA) of 0.36 grams per pound of body weight. We at Atria recommend closer to 0.7 to 0.8 grams per pound, or about 110 grams of protein per day for a 150-pound person who is looking to add muscle mass.

While total protein intake matters most, timing also plays a role—it’s important to space your protein intake throughout the day, rather than concentrating most of it at dinner time, as many people do. Aim to ingest a significant portion of protein every four hours when working to add muscle mass.

Total calorie intake is also crucial: "We actually need to eat at least at a maintenance level of calories, potentially even higher if we really want to optimize muscle mass," says Ross. To estimate your maintenance calorie level, he recommends 15 calories per pound of body weight for active people and 13 calories per pound for less active people. (An online Total Daily Energy Expenditure (TDEE) calculator can provide a more precise estimate.) While slight calorie deficits can work with adequate protein, maintenance or surplus calories typically yield better results.

Supporting nutrients

Beyond protein, other nutrients support muscle building. Ross highlights vitamin D for muscle tissue health, omega-3 fatty acids for strength and inflammation reduction, and electrolytes like magnesium, potassium, calcium, and sodium for proper muscle contraction.

While a little inflammation right after a workout can be helpful to stimulate the muscle repair that we want to see to increase mass, ingesting foods high in antioxidants several hours after a workout can be helpful to bring inflammation back down again.

Creatine can be a helpful supplement to aid in building muscle mass; it’s a good idea to consult your physician before adding it to your regimen.

The bottom line

While results take patience—often 6-8 weeks for beginners—the benefits include improved metabolic health, injury prevention, and successful aging. As the research shows, "those who have higher muscle mass have a higher chance of living longer and less chance of dying from all causes," says Sands.

Remember:

1. Seek professional guidance for proper form and progression
2. Master basic movement patterns before adding significant load
3. Start with 2-3 training sessions weekly, progressing to more depending on your goals
4. Focus on progressive overload over time
5. Prioritize protein at 0.7-0.8 grams per pound of body weight
6. Eat at maintenance calories (13-15 calories per pound of body weight) or slightly above