8 min read

The Illusion of Fast Muscle Growth and Loss

Why does it seem like you can seemingly gain muscle overnight sometimes? And then you lose it just as quickly? Don't be duped.
The Illusion of Fast Muscle Growth and Loss

I'm somewhat surprised when people tell me they don't know what "the pump" is.

Yet I'm rarely ever shocked that they don't understand the ramifications of fluid retention as it relates to training over the longer term. More importantly all the seemingly psychological trauma it causes. Okay that might be an exaggeration.

Or is it?

Today I'm going to explain how people get duped into thinking they've gained a lot of muscle quickly. When in reality all they've done is retain a bunch of water and dramatically altered water balance for a few weeks, maybe a month in some cases.

The Pump

I'll let Arnie explain "The Pump" because it'd be a crime not to:

Almost NSFW? There are sexual references in this video ...

πŸ˜†πŸ˜‚πŸ€£ Gets me every time.

The explanation isn't entirely accurate, and not everyone likes how the pump feels quite as much as Arnie did.

It's not so much blood, as it is interstitial fluid retention. Yes, your heart rate increases when you train and it moves more blood around more quickly as a result. But that blood is also returned to the heart just as quickly, or the heart would have nothing to pump.

Interstitial fluid is the middleman that sits between your blood vessels and your cells. Waiting to diffuse nutrients into the cell from the blood and holding waste products discharged out of the cells and for heading back into the blood.

When you train muscles to a fatigued state you dramatically increase the amount of waste products in the muscle cells and dramatically increase the flow of blood to provide nutrients.

Suddenly this middleman is the busiest courier service in town. It's got all these waste product packages to be sent to other parts of the body for processing and all these nutrient packages waiting to be picked up by the cells. And it's bursting at the seams!

It needs more space to hold everything, so the fluid volume increases to create more space to hold more nutrients and waste for transport.

This creates a bunch of outward pressure against the bigger outer pocket of connective tissue (fascia) surrounding the entirety of the muscle. Pushing out against your skin, where skin sensory feedback tells your brain that your muscles feel swollen. And they are, but it's not new muscle tissue just yet.

This is where you get your 'swole' on.

"The pump" is just swelling isolated to the muscles you've trained. Kind of like a low-level bruise but without any discoloration because it's not blood pooling, it's interstitial fluid.

It's important to note that weight and actual muscle size doesn't change. It's the space between muscle fibers that is suddenly packed with liquid pulled from other parts of the body that creates the illusion of a bigger muscle. But that muscle will return to its previous size given enough time to adequately supply the required nutrients and clear all the waste products.

Usually within a few hours depending on how hard you trained the muscle but fluid retention can actually last longer than that in some special situations. And those special situations can really mess with your training chi when it comes to weight loss or muscle gain.

You hope it comes back microscopically bigger if you're training for hypertrophy but that's neither here, nor there. The pump doesn't cause muscle hypertrophy, nor is it required to build muscle. It's just a term people use to describe a feeling of intense muscular swelling.

Bodybuilding Secret?

This phenomenon well known in bodybuilding circles and yet still seemingly less known in general population circles. It's not really a secret, because nobody has been keeping this information from you if you were willing to seek it out.

I'm not going to get in trouble for explaining all of this to you.

Before bodybuilders go on stage, in one last effort to reveal as much muscle under the skin as possible they do a few sets to failure for all the muscles they want to show off. Typically with moderate to light weights. The goal is to induce the pump and create the illusion of these muscles being bigger than they would normally be.

It's also something actors can also do this before shirtless scenes. Fitness models do it during photo shoots. And yes, you can do it before you head to the club on Friday night if you want too.

Beyond 'The Pump'

Now 'the pump' is short-term and well known in training circles. What is still lesser known or understood even in training circles is the longer-term implications of water retention. Especially in new trainees.

Usually because experienced trainees have long since passed that stage in their development, they've completely forgotten about it. Maybe they didn't even notice.

Some people don't. Most do. Especially women. Men tend to love it, and end up disappointed later when the water retention dissipates.

Now women have their own complicated issues surrounding water retention and menstruation that I'll leave for a separate article but even after the pump has come and gone, mild training induced edema ensues.

*Edema is the medical term for swelling.

Why Muscles Feel Bigger Days After Your First Training Session

Muscle recovery takes longer than a few hours. The typical path lasts about 48-72 hours, depending on how much muscle damage you caused with the training routine.

If you did a lot of training volume in very close proximity to complete or absolute failure that recovery process could take upwards of five maybe even six days. And that recovery process is aided by; You guessed it; A sustained increase in interstitial fluid!

While your muscles may not feel like they are going to explode anymore, they are still retaining more fluid than they were prior to your first lifting session in weeks, or months, or even years, while they recover from that stress you just applied in that last workout.

This can still give the appearance or illusion of bigger muscles. It's to a lesser extent than the pump, but it's still there. You can look kind of swole for a few days after you lift. But again, this is just water retention, not actual new muscle.

Countless men have been tricked into thinking they can stop training now because they clearly gained 10 lbs of muscle mass yesterday.

And countless women have been hoodwinked into thinking they 'bulk up quickly' and must stop training now or risk becoming bodybuilders by the end of the month.

In both cases, water retention has messed with your head and caused you to stop your training pursuit long before you can reap the benefits.

And although I say all that in jest, I'm not joking. I get asked questions about this all the time and I've seen it happen plenty of times. My hope is that if you can understand it better, you can push through to the other side. The side of the big reveal. Where the magic happens.

Water Retention Cycles and Masked Results

Compound into all of the above the issue being a beginner and the opportunity for more fluid intake and you see even more water retention over longer recovery cycles.


Because your body doesn't get used to to the training after only one bout of training. That takes some time and that's also why more experienced trainees don't experience this issue to the same extent. They recover better with less fluid retention.

Assuming you don't let that first training session swelling fool you into quitting early, then you will continue to train. Exposing your body to repeated cycles of edema and a seemingly perpetually 'puffy' or swollen look.

Hours after training, and the days that follow, you drink and eat as one does. And the body responds even further at this point by absorbing more and more fluid from that food and drink. Retaining a bunch of it between the cells and your blood once more. It's no longer a short-term thing where your body can just pull some extra fluids from areas of lesser need in a pinch.

Nope. It's chronic swelling now. Now after only a few weeks of training you might notice your scale weight has drifted up too. Uh oh!!! or Hell yeah!!!

Depending on how you want to view it.

But it's important to remember this isn't muscle. It's water retention.

In practice you might observe that water retention lingers for up to 1-2 months. But I'd say on average, it takes a beginner's body about 21-35 days to get used to whatever training program they are on.

It can dwindle after the first 2-3 weeks and you may observe scale weight going back down at that time. Leading to what some people call the 'whoosh' effect. Whereby instead of gaining a bunch of muscle seemingly overnight from the pump and the edema that lingers; You actually lose a bunch of water weight overnight. Upwards of 5-10 lbs even.

The body is weird like that, what can I say. This is why I always make the distinction between weight loss and fat loss, because weight loss is very often water. And water isn't really what you want to gain or lose.

From the beginner-stage onward, changing your exercise programming – as one probably should do cyclically – can still lead to excess water retention but the durations are shorter for future changes. Lasting maybe a week or two at most and being far less visible to the naked eye, with far less scale weight being altered too.

The first week or two of a training program (a good one anyway) will yield the strongest effect in this respect because the first part of a new training program induces the most muscle damage. Excessive amounts of muscle damage interrupts the growth process. It’s a new program after all.

Water retention adapts pretty well after what I would call a 'base phase' or programming or a 'foundation phase' of programming. A purposeful approach tp programming that prepares your body to manage this introductory part of the process. And it's also something to consider if you're returning to resistance training after a lengthy period of time off.

The problem however, is that if you don't wait this period out, and give it at least the full 21 days of consistent training to run it's cycle, you never experience your whoosh, and you never realize how little muscle you've actually gained. Or how much fat you've also potentially lost.

The first month of a new training program will often seem like nothing is happening, until all of a sudden it does. Be patient.

When Does it Become Muscle?

Muscle growth takes considerably more time than one workout. Considerably more time than even a bunch of workouts strung together.

The overwhelming majority of research suggests that beginner trainees don’t lay down any appreciable muscle mass for ~6–7 weeks of training.

That's a long time. There are a bunch of reasons why that I won't get into, but if you think you've bulked up considerably in your first month or two training.

Remember that you probably haven't.

By all accounts it takes about 10 lbs of lean mass to be noticed by other human eyes. Β This will yield about an inch of additional circumference around key growth areas (arms, legs, chest, shoulders, etc...) you've been training.

A realistic expectation about building this much mass is probably 4-6 months if you're absolutely new to lifting. Mostly because that first 1-2 months is just getting your body used to handling the training.

You have to push through the first 6–7 weeks with consistent progressive overload training if muscle growth is your goal.

Water retention is a pain in the &$$. This swelling effect is extremely deceiving and gives people false hope and discouraging results sometimes too.

Sometimes it takes weeks (or in this case months) to observe the real trends of your workout or nutrition programs. That's why I generally recommend taking weight with girth measurements

Do your best to avoid knee-jerk reactions to short-term situations. You probably didn't gain muscle that quickly. If that's a problem, wait, it'll go away. If it's what you're after, keep training because it will go away.

And not just when you're new to training. It will continue to mess with you your whole training life too.

Wake up dehydrated after a night out partying and drinking, or a marathon or something and look in the mirror to see an incredibly lean individual? Rehydrate, take in some salt and go back to normal. πŸ™

Go low carb for a week or so and the same thing can happen. Eat a big meal in carbohydrates and salt after low carb dieting for a while and you'll puff back up. It can feel like one big carb meal ruined all of that dieting and make the whole process feel hopeless.

Don't let it, because that's not what's happening. Your body is a fickle creature when it comes to water balance.

You have to keep your eye on the prize. The goal is to keep the goal the goal.