It’s frustrating to find come home from your workout and look in the mirror to see a stomach puffed up like a balloon. What possible reason could there be for you to enter a gym with a (relatively) flat stomach, yet emerge 60 minutes later looking six-months pregnant?

This happens to us all the time and so we wanted to know why it occurs.
Now, assuming you rule out the incidence of some weird gym machine impregnation (like that woman who ate the dodgy squid piece and ended up with squid babies) because, let’s face it if I don’t that’s me and the lat pulldown parting company from now on, I’m figuring it must be something to do with my ‘I puff up like a balloon given the slightest opportunity’ stomach,’ so I asked Kesh Patel, Research and Development Manager for Premier Training International the big question…
Why Does My Stomach Look Bigger After Working Out?
Kesh’s response is that I’m likely swallowing air as I exercise.
‘This is quite normal and very common during high-intensity work or weights – as during this type of work you tend to hold your breath occasionally,’ Kesh tells me.
‘When you take a breath in after a breath-hold it’s invariably larger than normal and some air escapes into the stomach.
During rest, this would escape as a burp, but, the high intensity of exercise may keep the stomach constricted and prevent this from happening and so you become bloated.’
The problem also gets worse apparently if you’re dehydrated when you exercise – a dry mouth triggers you to swallow more and as you do that you gulp in air as well. Hmmm, breath-holding and dehydration – yep, that sounds like me at the gym….
How to Stop It
After all, it’s a tad frustrating when you plan your pretty Saturday night outfit around a pencil skirt- and yet, by the time you get home from the gym your stomach is not pencil skirt friendly.
Kesh says the key is to breathe as regularly as possible, not hold your breath – and take more sips of water.
Gym bloating is also more likely to happen after higher intensity workouts so if you are exercising before you want to slip into something tight, it might help to keep your session low to moderate in intensity.
Other Reasons Why Gym Bloating Happens
You might also just be caught out by bad timing. Many foods, particularly healthy foods, have the ability to make us bloat – most common triggers are foods high in fibre like whole grains, nuts, seeds (including chia seeds) and items high in a substance called resistant starch which includes beans, pulses and, frozen bread.
The bloating effects of these kick in about 2-3 hours after you’ve eaten them once the food moves the gut and the bacteria there start to work on things. If you ate a late lunch, you could find your bloating is triggered just as you get to the gym for your post office workout.
Stopping this kind of bloating will mean adapting what you eat, when you eat or how you eat it – you’ll find heaps of tips on this in the links above.
Weight Gain When Working Out
Of course, you might have stumbled across this piece not because your stomach is suddenly bigger when you’re working out, but because you seem to be gradually gaining inches around the middle even though you’re exercising.
This is frustrating side of why your stomach can be bigger after exercise! After all, you’re working hard, surely you should be shrinking not gaining?
Now, there’s no one reason for this happening, but here’s a couple that experts have told me over the years.
The first is that you’re eating more calories than you’re exercising off. This is the most common reason why exercise leads to weight gain around the middle. Fact is, while exercise is very good for us for a number of reasons, done alone it actually sucks as a weight-loss method.
Running for an hour burns about 600 calories – you can wipe all of that out with a smoothie on the way home.
And the fact is, we normally overestimate how hard we’ve worked at the gym and how many calories that might translate to us losing and we underestimate how calories we eat.
This mismatch is the number one reason why exercise doesn’t trigger weight gain – you have to change both your diet and your exercise if you want to lose weight and you need to be realistic about the balance sheet if you want to ensure you don’t gain it.
But what if you weren’t aiming to lose weight and yet you’ve started gaining it? Well, the fact is that exercise might cause us to eat more, partly because it can affect levels of appetite hormones, but. there’s also a little psychological trick called the moral licensing effect that might be coming into to play.
This is the idea that if we’ve done something good for yourselves (like go to the gym) then it’s okay for us to do something not so great – like have extra fries with your dinner. The problem is, when you’re trying to lose weight, the not so great thing often cancels out the benefits of the good thing – and you end up either back to square one, or tipping that calorie balance and gaining weight.
You need to focus on your goals and not be diverted by shiny plates of chips or ice cream calling your name.
Lastly, when it comes to gaining weight around your middle when you’re exercising, stress might be playing a role.
I learned this tip from trainer Dalton Wong and it’s stuck with me.
His theory is that exercise is a stress on the body – and while most of the time its benefits are positive, if you’re stressed out in other areas of your life and you do heaps of hard of workouts, the combination of life stress and exercise stress can raise cortisol levels – and cortisol causes you to pack on pounds around your middle.
For this reason, Dalton suggests his stressed-out clients alternate each cardio session with two easy ones and ideally chill out for 30 minutes before hitting the gym if they exercise after work. Every three weeks they also take a week off the hard cardio just doing walking and yoga instead.
So, there you have it a number of reasons why your stomach might be bigger after working out. Do any of them sound like you?
Image: freedigitalphotos.net

Who is The Wellness Nerd?
My name is Helen Foster and I’m a health journalist and wellness author. Publications I’ve written for include Women’s Health, Reader’s Digest, Body and Soul, Good Health at the Daily Mail and more. I have also written 16 books on health and nutrition.