Why Do My Muscles Look Smaller After a Workout? (Solved!)

Last updated on September 16th, 2022 at 10:08 am

It’s almost unthinkable but, “Why Do My Muscles Look Smaller After a Workout?”

You go to the gym, you hit the weights hard, all in the name of hypertrophy.

However, nothing can feel more devastating than your muscles actually looking smaller following your workout.

And yet, this appears to be an extremely common occurrence.

So, what exactly is going on here?

Allow me to reveal all.

Why Do My Muscles Look Smaller After a Workout?

The most obvious reason that your muscles look smaller after a workout is that initially they achieve a temporary increase in size while you workout, often referred to as the “pump”. This simply means that blood flow increases and the blood vessels expand. However, this typically only lasts for a few hours. Additionally, muscle glycogen and water will deplete overnight, as these are still required for your brain and organs to function. Furthermore, improper nutrition following a workout can contribute to your muscles looking smaller after a workout.

1. The Pump Has Gone

I’m sure you’ve heard of muscle “pump” and indeed experienced it.

In its most basic form, a pump is a temporary increase in muscle size.

This typically occurs when you lift weights, and is especially true when you use higher rep ranges or shorter rest periods.

Basically, when you’re lifting weights (or performing any form of exercise) your body will heat up.

Your blood vessels will expand in order to release this excess heat.

And as your blood vessels are now larger, more blood can travel through them in order to transport oxygen to your muscles.

So, in effect, your muscles will look and actually be larger while you’re working out.

This also explains why you sweat, and your body will release excess nutrients and water through the skin.

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However, as I’ve mentioned, this is only a temporary effect.

So, once your workout is over your blood vessels will typically reduce back to their normal size.

In essence, your heart is longer working as hard, and your blood vessels are no longer required to transport as much blood for oxygen to your muscles.

I will also say that you will generally pay far more attention to your muscles while you’re working out.

Therefore, you can actually see that your muscles appear larger and “pumped”.

However, once you’ve stopped exercising, your muscles will actually “shrink”, as they no longer require the extra oxygen.

The muscle pump from working out will typically last 2-3 hours, although this could also be more or less depending on the intensity of your training session.

So, it could be a case that once your workout is over, you’re back from the gym, showered and settled down, your muscles will have returned to normal size.

And this could explain why your muscles appear to look smaller after a workout.

2. Muscle Glycogen & Water Depletion

Now, a similar question I often see is, “Why do my muscles look smaller in the morning?”

So, in effect, you go to bed and your muscles appear pumped, but when you wake up the following day your muscles seem to have significantly decreased in size.

This typically comes down to how your body and internal organs use your main sources of energy.

Your workouts are usually fuelled by glycogen, which is how carbohydrates are stored in the body.

The majority of glycogen is stored in the skeletal muscles and the liver.

Furthermore, glycogen will require water in order to be stored in the body.

Now, during the initial stages of exercise, as well as if you’re on a calorie-restrictive diet, these stores of glycogen will deplete.

This also explains why you’ll typically run out of energy and become more fatigued the longer your workout goes on .

However, while you sleep your body still requires energy from glycogen in order for your vital organs to function.

With that being said, if we take the brain as an example, glycogen is actually taken from the liver for your brain to function while you sleep.

However, you also have to realise that while you sleep you are in effect “fasting”, and therefore your skeletal muscle glycogen will also decrease.

And let’s not forget that glycogen requires water to fulfill its purpose.

So, in effect, your muscles have had much of their energy source taken away from them while you sleep.

And this will explain why your muscles actually look smaller in the morning.

3. Lack Of Proper Nutrition After a Workout

You’ll note that I’ve mentioned that our muscle glycogen stores are typically created from carbohydrates.

And this can actually go a long way to explain why your muscles look smaller after a workout.

I can guarantee that the vast majority of trainees focus much more on protein intake following a workout.

And this does make a lot of sense, as your muscles require protein to grow.

So, many of us will typically take a whey protein shake immediately after our workout.

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What we’re really trying to do here is to adhere to the principles of the “anabolic window” or the “golden hour”.

Basically, the aim is to ingest some fast-absorbing proteins, which in turn will deliver amino acids into your bloodstream when they are required most.

This will help your muscles to recover faster and eventually grow back bigger and stronger.

Plus, your muscles will absorb more nutrients straight after a workout.

With that being said, this is also the ideal time to replace your depleted glycogen stores, and following your workout is the most efficient time to do this.

However, many of us focus on protein intake in the 45-60 minutes following a workout, but not so much on the other macronutrients.

So, while you may be helping your muscles to recover and grow at some point in the future, you’re also ignoring the need to fill up on glycogen.

Therefore, if you’re not consuming protein, carbohydrates, and healthy fats following a workout, you could be missing out on potential gains.

Plus, once again, this will explain why your muscles don’t look as big or pumped following your workout.

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4. Are You Suffering From Muscle Atrophy?

So far I’ve covered the most obvious reasons for your muscles looking smaller after a workout.

These are far more aligned to the usual experiences that we all go through.

However, that is not to say that something more untoward could be happening.

Something else to consider is muscle atrophy.

Firstly, when you workout and your diet is correctly aligned with hypertrophy, or the muscle-building process, you should hopefully see gains.

Okay, this isn’t an overnight process, but progressively overloading your weight training and eating sensibly at a calorie surplus should see you get stronger and bigger.

Why Do You Need to be in a Calorie Surplus to Build Muscle?

This is typically known as an anabolic process, i.e. you are promoting metabolic activity which can lead to muscle growth.

However, the opposite of this is the catabolic process, whereby you are actually breaking down muscle tissue, as opposed to growing it.

So, muscle atrophy is once more the opposite to muscle hypertrophy, whereby this is the progressive degeneration of muscle tissue.

And unfortunately the way you train and eat will have a massive impact on this.

I don’t really want to get into the realms of overtraining, as this is extremely difficult for most of us to do.

However, that’s not to say that your training is actually harming muscle growth.

You have to remember that every time you hit the gym you are actually damaging the muscle tissues.

So, tiny microscopic tears occur in the muscle tissues whenever you exercise.

This is why you need to rest, recover, as well as provide your damaged muscle tissues with adequate nutrients to repair themselves.

So, while it may not be specifically considered overtraining, if you are frequently hitting the same muscle groups you are not allowing them to repair and recover.

In effect, you are damaging the muscle tissues over-and-over again and not allowing them to heal.

Eventually, this will catch up with you and can cause your muscles to get smaller.

This is why rest days are so important, and also why you’ll often hear that you need 48-72 hours rest before you work the same muscle group again.

With that being said, I see nothing wrong with specialization training where you hit the same muscle group multiple times a week.

However, this should typically only be done for 2-4 weeks at a time before allowing your muscles ample time to recover.

Be honest, are you allowing your muscles sufficient rest and recovery time, as well as feeding them with the required nutrients?

5. Could You Be Losing Fat?

The final thing to consider is fat loss, which is never a bad thing.

You can be in fairly good shape, but still be carrying excess fat.

I guess the most obvious place that we can look to confirm this is our abs.

In essence, you can be extremely fit, strong and muscular, but still not be able to see your abs.

Then again, as seems to be the case for many people, only your upper abs are visible.

Why Do I Have Upper Abs But Lower Belly Fat?

In reality, for men we won’t typically see our abs at all until we’re around 10-15% body fat, and at around 18-22% for women.

However, you must remember that it is pretty much impossible to spot reduce body fat.

With that being said, if you can’t yet see your abs then it is likely that you are still holding onto body fat in other areas of the body.

So, if it appears that your muscles are getting smaller over a period of time, this could actually be nothing more than fat loss.

As an example, your biceps may look absolutely fantastic when flexed, but still be soft.

Why Are My Biceps Soft When I Flex?

This will typically occur because you still have fat around your arms.

However, let’s say you’re regularly performing high-rep, short-rest bicep curls, you will not only receive a “pump”, but you’re also likely to be burning fat.

So, your muscles looking “smaller” isn’t always a bad thing.

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Final Thoughts

So, as you can see, there are actually numerous reasons why your muscles look smaller after a workout.

The most obvious of these is that the “pump” you achieve at the gym will typically only last for a short period of time.

However, through progressive overload training and proper nutrition you can of course experience muscle growth.

Furthermore, if you notice your muscles look smaller the following morning, this comes down to muscle glycogen depletion.

Additionally, while you may currently be taking protein post-workout, you should also be consuming carbohydrates to replenish your glycogen stores (and don’t forget healthy fats either).

With that being said, if you’re noticing that your muscles are getting smaller over time, this could be down to not adhering to proper rest, recovery, and nutrition.

Finally, it could actually NOT be a case of your muscles getting smaller, but rather that you’re losing body fat.

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