Anabolism - How Your Body Builds Muscle (and Why It Matters More as You Get Older)
If you’ve ever wondered how your body actually builds muscle, the answer lies in a process called anabolism.
It sounds technical, but the idea is simple. Anabolism is the process where your body builds and repairs tissue. When it comes to strength training, it’s the process that helps your muscles grow stronger after exercise.
Understanding anabolism can help you make better decisions about training, nutrition, and recovery, particularly if you're over 35 and want to stay strong, lean, and active.
What Is Anabolism?
In simple terms, anabolism is the building side of your metabolism.
Your metabolism has two main processes:
Catabolism: breaking things down (like when you digest food or use stored energy during exercise)
Anabolism: building things up (like repairing and growing muscle tissue)
When you lift weights or perform resistance training, you create tiny amounts of stress and micro-tears in muscle fibres. This is completely normal and part of the process.
Your body then responds by repairing those fibres and making them slightly stronger than before. That repair process is anabolism at work. Over time, this is how muscles grow stronger and more resilient.
Why Strength Training Triggers Anabolism
Muscle growth doesn’t happen during your workout. It happens afterwards, while your body is recovering. Strength training creates a signal that tells your body: “These muscles need to be stronger next time.”
In response, your body increases muscle protein synthesis, the process of building new muscle proteins.
Research has consistently shown that resistance training is the most effective way to stimulate this anabolic response, particularly as we get older (Phillips et al., 2016).
Without that stimulus, the body has little reason to maintain or build muscle tissue.
The Balance Between Building and Breaking Down
Muscle growth depends on a simple balance. If muscle protein synthesis (building) is greater than muscle protein breakdown, you gain or maintain muscle. If breakdown exceeds building, muscle mass gradually decreases.
This balance becomes increasingly important as we age because of a natural process called sarcopenia, the age-related loss of muscle mass.
Studies suggest adults can lose 3–8% of muscle mass per decade after age 30 if they are inactive (Cruz-Jentoft et al., 2019).
The good news is that strength training and adequate protein intake can dramatically slow or prevent this loss.
Nutrition: The Fuel for Anabolism
Exercise starts the process, but nutrition supports it.
Muscle repair requires protein, which provides the amino acids needed to rebuild tissue.
For many adults, particularly those over 35 or 40, increasing protein intake can make a noticeable difference in recovery and muscle retention.
Current research suggests that physically active adults benefit from around:
1.2 – 1.6 grams of protein per kilogram of body weight per day (Morton et al., 2018).
Good protein sources include:
Eggs
Fish
Chicken and lean meats
Greek yoghurt
Tofu and tempeh
Lentils and beans
Whey or plant-based protein powders
Spacing protein across meals throughout the day can also support muscle protein synthesis more effectively than having it all in one sitting.
Recovery: The Missing Piece of the Puzzle
Anabolism doesn’t happen during your workout - it happens while you recover.
That means sleep, rest, and recovery are just as important as the exercise itself. Three key factors support anabolic recovery:
Sleep: During deep sleep, the body releases hormones that support tissue repair.
Nutrition: Protein and adequate calories allow your body to rebuild muscle.
Rest between sessions: Muscles need time to recover before being trained again.
This is why well-structured training programmes alternate muscle groups and include rest days.
Why Anabolism Matters More After 35
As we get older, the body becomes slightly less efficient at building muscle - something scientists call “anabolic resistance.”
This simply means the body needs a slightly stronger signal from exercise and nutrition to stimulate muscle growth.
The solution isn’t extreme training. Instead, it’s consistent resistance training combined with adequate protein intake.
For many of the clients I work with in Oxford, this approach leads to improvements in:
Strength
Body composition
Energy levels
Bone density
Long-term mobility
The Takeaway
Anabolism is simply your body’s natural process of building and repairing tissue.
To support it, three things matter most:
Strength training to stimulate muscle growth
Adequate protein to provide the building blocks
Proper recovery to allow repair to take place
When those three elements work together, your body becomes stronger, healthier, and more resilient.
And that’s exactly what we want from training - particularly as we get older.
If you're based in Oxford and want to build strength in a way that works for your age and lifestyle, get in touch — I'd love to help."
Written by Alan Griffin, qualified personal trainer and founder of Griffin Fit, Headington, Oxford
Frequently Asked Questions:
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Anabolism is the process your body uses to build and repair muscle tissue after exercise.
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Research suggests around 1.2–1.6g per kilogram of body weight per day for active adults.
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Yes - consistent resistance training and adequate protein can build and maintain muscle at any age.
References:
Cruz-Jentoft AJ et al. (2019). Sarcopenia: Revised European consensus on definition and diagnosis. Age and Ageing.
Morton RW et al. (2018). A systematic review, meta-analysis and meta-regression of protein supplementation on resistance training–induced gains in muscle mass and strength. British Journal of Sports Medicine.
Phillips SM et al. (2016). Resistance exercise: good for more than just Grandma and Grandpa’s muscles. Applied Physiology, Nutrition, and Metabolism.
