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.
The most obvious reason that your muscles look smaller after your 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 this.
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 when training, and your body will release excess nutrients and water through the skin.
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.
Muscle Glycogen & Water Depletion
Now, a similar question I often see is, why your 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.
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 aren’t looking that great following a training session.
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.
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.
Are You Suffering From Muscle Atrophy?
So far I’ve covered the most obvious reasons for you 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.
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?
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.
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.
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.
Frequently Asked Questions
Here’s some frequently asked questions on the subject of your muscles looking smaller.
Please note that irrespective of when you notice these fluctuations it typically comes down to many of the points I have already discussed.
Why Do My Muscles Look Smaller Some Days?
There are several reasons why your muscles might appear smaller on some days, even if you’re diligently sticking to your workout routine.
However, in truth, the vast majority of the time this is due to the factors I have already mentioned.
Don’t forget, temporary fluctuations are perfectly normal, but here are the main culprits for looking “big” some days and not so much on other days.
Muscle Pump Deflation
Once again, the main reason is simply that you may not be as “pumped” on certain days compared to others.
This is due to decreased bloodflow a few hours after exercise.
So, depending on when you last worked out, or the type of workout you last performed (you wouldn’t expect your chest to look “pumped” after leg day), your muscles can definitely look smaller some days.
As I’ve mentioned previously, your workouts are typically fuelled by glycogen.
Plus, your levels of glycogen will slowly deplete based on how much energy you’re using.
So, glycogen depletion can make your muscles look less full or rounded, contributing to that smaller appearance. However, proper post-workout nutrition will replenish these stores within a few hours.
Microtears and Repair
Don’t be alarmed!
Exercise actually creates tiny tears in your muscle fibers.
This might sound counterintuitive, but it’s crucial for growth.
Your body repairs these tears with stronger, thicker muscle fibers over time, leading to long-term growth.
This process can create a temporary feeling of “deflation” as your muscles are in the repair phase.
Water is essential for muscle cell volume.
Even mild dehydration can cause your muscles to appear flatter and less defined.
Make sure to stay hydrated throughout the day, especially before, during, and after workouts, to keep your muscles looking and feeling their best.
Sometimes, it’s not our muscles shrinking, but our perception changing.
Factors like fatigue, lighting, and even stress can influence how we see our bodies.
Remember, consistency and progress trump temporary fluctuations.
Don’t let a temporary smaller appearance derail your dedication.
Focus on progressive overload: Gradually increase the weight, reps, or sets in your workouts to constantly challenge your muscles and stimulate growth.
Prioritize protein intake: Protein is the building block of muscle tissue. Aim for a minimum of 0.8-1 gram of protein per pound of body weight daily.
Get enough sleep: Sleep is crucial for muscle recovery and growth. Aim for 7-8 hours of quality sleep each night.
Track your progress: Take progress photos or measurements to measure your long-term gains, rather than focusing on daily fluctuations.
Why Do My Muscles Look Smaller at Night?
There are a few reasons why your muscles might appear smaller at night compared to earlier in the day, whether you’ve exercised or not.
Furthermore, as you might expect, the majority of these reasons are factors that I’ve already discussed.
Throughout the day, your body naturally loses fluids through sweat, urination, and even breathing.
If you haven’t been replenishing those fluids adequately, dehydration can set in by nighttime.
This can cause your muscle cells to shrink slightly, leading to a less defined, “smaller” appearance.
Your Glycogen Stores Are The Issue Once More
By nighttime, your glycogen stores might be depleted, especially if you haven’t eaten well throughout the day.
This depletion can make your muscles look less full and contribute to a smaller appearance.
Fatigue and Perception
As the day progresses, fatigue sets in, and your perception of your body can change.
You might be more critical of your appearance at night compared to the morning, noticing slight changes in muscle definition that wouldn’t have bothered you earlier.
Additionally, factors like lighting and posture can also influence how you perceive your muscle size.
Muscle Repair and Recovery
If you exercised earlier in the day, your muscles might be in the repair and recovery phase at night.
This process involves inflammation and fluid buildup around the muscle fibers, which can temporarily mask their definition and make them appear slightly smaller.
However, this is a positive sign, as it indicates your body is rebuilding and strengthening your muscles.
Throughout the day, your body experiences fluctuations in hormone levels, including cortisol and testosterone.
These hormones can affect muscle metabolism and fluid balance, potentially contributing to minor changes in muscle appearance.
Tips to Minimize Muscle Shrinkage at Night
Stay hydrated: Drink plenty of water throughout the day, especially before and after exercise. Aim for 8 glasses of water per day, and adjust based on your activity level and climate.
Eat a balanced diet: Focus on consuming complex carbohydrates, lean protein, and healthy fats throughout the day to keep your energy levels stable and glycogen stores replenished.
Get enough sleep: Aim for 7-8 hours of quality sleep each night. Sleep is essential for muscle recovery and repair, which can help maintain muscle definition.
Manage stress: Chronic stress can lead to cortisol spikes, which can negatively impact muscle growth and recovery. Practice stress management techniques like meditation or yoga to keep cortisol levels in check.
Track your progress: Instead of focusing on daily fluctuations, track your muscle size over time by taking progress photos or measurements at regular intervals. This will help you see the bigger picture and stay motivated.
Remember, small changes in muscle appearance throughout the day are normal and don’t necessarily indicate muscle loss.
By staying hydrated, eating well, getting enough sleep, and managing stress, you can minimize these fluctuations and maintain healthy, defined muscles.
Why Are My Muscles Getting Smaller But I’m Getting Stronger?
It seems confusing that your muscles might be getting smaller while you’re getting stronger!
But, this is not something to fear, this is actually a positive sign and perfectly normal.
Muscle Composition Shift
Building muscle isn’t just about adding bulk.
When you train, you’re not just increasing the size of muscle fibers, but also their density and efficiency.
This means you can generate more force with the same or even slightly less muscle mass..
Increased Neural Efficiency
Strength gains can also come from improved communication between your brain and muscles.
This means your nervous system can recruit more muscle fibers at once and activate them more effectively, leading to increased strength without significant size changes.
Water and Glycogen Fluctuations
Your muscles hold onto water and glycogen for energy, which contributes to their appearance.
As I’ve mentioned, this can fluctuate throughout the day, appearing smaller after strenuous activity or when glycogen stores are depleted.
Don’t worry, these natural fluctuations don’t signify muscle loss.
Bodyfat Composition Changes
If you’re simultaneously strength training and losing body fat, you might notice a decrease in overall muscle size while gaining strength.
This can happen because fat loss tends to occur evenly across the body, including areas around muscles.
However, the underlying muscle tissue is getting stronger.
Here are some ways to confirm and track your progress:
Strength gains: Track your performance on compound lifts like squats, deadlifts, and presses. If you’re lifting heavier weights or doing more reps, it’s a clear sign of strength building.
Performance improvements: Notice if you’re performing better in everyday activities or sports. Increased stamina, speed, and power are indicators of strength gains.
Body composition measurements: Consider using tools like bioimpedance scales or body fat calipers to track your body fat percentage alongside weight or muscle mass measurements. This can provide a more holistic picture of your progress.
Focus on consistent training and proper nutrition, both are crucial for muscle growth and strength development.
Don’t get discouraged by temporary fluctuations in muscle size. Track your progress over time and celebrate your strength gains!
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.
Want to pack on muscle within the next 12 weeks? Plus, wouldn’t it be great to achieve this without getting fat? Then you’ll want to follow the Massthetic Muscle workout program.
Hi, I’m Partha, owner and founder of My Bodyweight Exercises. I am a Level 3 Personal Trainer and Certified Strength & Conditioning Specialist through the Register of Exercise Professionals, United Kingdom. I have been a regular gym-goer since 2000 and coaching clients since 2012. My aim is to help you achieve your body composition goals.