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Bra Fit and Sodium – Does it Really Matter?


We’ve all heard and experienced the dreaded “retaining water.” Ever have those days when your pants just don’t seem to fit properly, or when you feel bloated and gross? Chances are you haven’t actually gained any weight – you’re just “retaining water.” This is especially true if you find that you go up or down a few pounds on the scale every day – such large fluctuations aren’t caused by weight loss or weight gain, but are instead all about sodium and hydration. So the $100 question – does sodium matter to bra fit?

The Science of Water Retention
Make no mistake about it – water retention is a real thing, backed by science. How does it work?

Our bodies rely on electrolytes to carry electrical impulses. The most significant sources of electrolytes are sodium and potassium. Too many electrolytes in the blood triggers thirst, which makes us drink more water to equalize the electrolytes. When we drink enough water, the kidneys regulate the electrolytes in the blood by increasing or decreasing the amount of water we retain.

The water in our bodies gets kinda complicated. If you’re familiar with osmosis, you probably know that water flows from a lower salinity environment to a higher one until the salinity is balanced. Similarly, the water in our bloodstream moves into our skin after we consume a large amount of salt in an attempt to balance salinity levels. This is what gives our skin the “puffy” look – if you’ve ever had trouble getting a ring off that normally fits well, that’s what’s going on. When we consume less salt, the same process works in reverse and removes the excess water from our bodies.

It may seem complicated, but at the core, consuming too much sodium throws our electrolytes out of balance and causes our bodies to retain more water until the excess sodium is balanced. Less sodium equals less water retention – which means the body is thinner and lighter.

It’s science. Water retention is a real thing.

So can Sodium Affect Bra Fit?
Short answer: you bet! As with all your other clothes, your bra may fit more snugly or have trouble closing if you’ve consumed an unusual amount of sodium. It’s the same principal as when your pants are too tight and you feel bloated when you’re retaining water. The rest of your clothes do the same thing, which is why some shirts may not seem to fit right.

Fortunately, most bras have enough stretch and give that it’s not a huge problem when we’re retaining a little water. The bra may fit a little snugly, but it should still be wearable – particularly comfort-oriented bras that are made of fabrics designed to give a little.

If you find that there are days when your favorite bra doesn’t seem to fit properly and it’s actually uncomfortable, you can try one of two things: either buy the same bra in a size up, or invest in a sleep leisure bra or other type of comfort-oriented bra for days when you’re retaining water. This can also be useful if you find that your bras fit differently at different points in your cycle.

(Yes, that’s another real thing! Being a woman can be so complicated!)

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