Catabolic Myth: Can Long Workouts Make You Lose Muscles?

Embarking on a fitness journey can be transformative, almost addictive when you experience the life-changing impact it has on your life. The sculpted physique you built throughout the years is a physical manifestation of your dedication and self-discipline. More importantly, pushing the boundaries of your limitations makes you feel good about yourself, allowing you to become resilient both physically and mentally.

Sometimes, we enjoy working out and spending more hours in the gym. However, it's a common question in the fitness circle: could spending long hours in the gym actually be counterproductive for muscle growth? Can long hours of exercise lead to muscle loss?

This article will discuss the science of metabolism and explore catabolic myths so you can make an informed decision about your fitness and health.

Metabolism refers to the process of how the body turns food into energy. The body uses that energy to build and repair tissues, like muscles. Achieving optimal muscle growth requires the body to consistently balance two processes: building (anabolism) and breakdown (catabolism).

Anabolism is the process of building up tissues.

When you eat protein-rich foods, your body breaks them down into simpler forms of amino acids, which act as the building blocks for constructing new muscle cells.

Exercising, especially while lifting weights, creates tiny tears in your muscle fibers. These micro-tears in the muscle tissues are essential to signal your body that it needs to repair and grow stronger muscles.

During recovery, the anabolic process kicks in. Using amino acids from your diet, your body repairs damaged muscle tissues, making them thicker and stronger than before.

This process results in muscle growth over time.

Anabolism > Catabolism = Muscle Growth

Muscle catabolism is the opposite of anabolism. It is the process where muscle tissues are broken down by deconstructing complex muscle proteins into simpler amino acids.

While 'breakdown' carries a negative connotation, muscle catabolism is essential to achieve a balanced metabolism. Your body uses this process to provide energy, especially when you are not getting enough nutrients from your diet. This allows the body to allocate energy sources where they are needed most.

Muscle loss can occur if catabolic activity outweighs anabolic activity for long periods.

Catabolism > Anabolism = Muscle loss

Not necessarily.

While it is true that shorter and more intense exercises ranging from 30-60 minutes are geared toward putting your body in an anabolic state, it doesn’t mean that longer exercise duration puts your body in a catabolic state.

Before you start burning your own muscles for energy, your body has to deplete your glucose (sugar) in the bloodstream for immediate energy needs. Once those are depleted, the body taps into glycogen (sugar stored in other tissues) for energy.

After exhausting glycogen, your body looks for alternative sources, such as fat stores. Only after depleting all means of energy in your body will your body break muscle protein for fuel, leading to muscle catabolism.

Studies have shown that longer hours of strength training don’t negatively affect muscle growth. Longer time in the gym could mean more time to perform more exercise. This effectively translates to higher exercise volume, which is a prime driver for muscle growth.

You have to deplete your other energy stores before your body starts using muscles for fuel

It is important to note that movements and exercises can prevent muscle atrophy or muscle loss. Studies have shown that even cardioaerobic activities such as treadmill running can also improve the leg muscle size.

However, endurance exercises such as long-distance running, cycling, swimming, and other cardioaerobic activities are particularly susceptible to putting the body in a catabolic state.

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Endurance activities consume large amounts of glycogen to sustain long-term muscle activities. More than 90-120 minute endurance exercises can force the body to tap for muscle stores for energy.

If proper nutrition and hydration aren’t maintained during your workout sessions, your body may enter a catabolic state.

Prolonged endurance exercises, with inadequate nutrition, can trigger catabolic state

Pre-workout nutrition

Meal timing is also vital for the muscle-rebuilding process.

Consuming a balanced meal rich in macronutrients such as carbohydrates and protein 1-2 hours before a workout can provide enough energy to sustain your activity and minimize the risk of muscle breakdown.

Following an intense exercise session, eating a protein-rich meal or snack can help replenish your energy, aid muscle repair, and create new muscle cells.

It is essential to consume your meals during the anabolic phase of your body to promote protein synthesis and maximize your muscle gains. Resistance training, in particular, is an excellent trigger for the anabolic process.

To build more muscles, you need to eat enough calories to support your muscle growth. Essentially, your calories are your fuel to support your activities. If you don’t consume enough calories, your body will look for stored energy (sugar, fats, muscles) to sustain your current activity level.

If you are trying to lose stubborn fats and chop off some weights, you can still build muscle mass through body recomposition while staying calorie-deficit.

Sleep is a crucial part of your fitness journey. During sleep, your body releases essential hormones like growth hormones and testosterone to support muscle development. Aim for at least 6 to 8 hours of sleep per night.

Improper periodization of your workouts or too much training can lead to a fitness plateau and overtraining. Too much exercise without rest can lead to higher cortisol levels, triggering catabolic processes leading to weight gain and muscle loss.

Here’s a plan for woman that will help boost anabolism:

And for men:

If you want to build more muscles and avoid muscle loss, you need to be in an anabolic state more often. This means focusing on activities and nutritional choices that promote muscle growth and repair while minimizing factors that lead to muscle breakdown.

Anabolic Activities Catabolic Activities
Heavy weightlifting

Compound exercises

Targeted isolation movements

High-intensity Interval Training (HIIT)

High protein intake

Carbohydrate timing

Essential fatty acids


Rest days

Active recovery




Branched-Chain Amino Acid

Long distance running


Low protein intake

Too much calorie deficit


Lack of sleep


High-stress level

Overuse of caffeine

Chronic illness

Medications (Corticosteroids)

Lack of periodization

Imbalanced workouts

Extended time in the gym isn’t necessarily bad for your muscle gains. In fact, more time working out could mean more exercise volume, which is critical for muscle building. However, inadequate nutrition, overtraining, and too much endurance exercise can trigger your body to enter a catabolic state, leading to muscle loss over time.

The key is finding balance in everything you do. A holistic approach to training, recovery, and nutrition is the key to improving your muscle gains and minimizing the risk for muscle loss.

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