Why Do I Stink When I Work Out?

Recently, I was asked by a concerned fitness enthusiast why their sweat had such a horrific stench post-workout, and what they could do about it.

But the fact is, sweat doesn’t stink.

When it comes to body odor, sweat certainly gets a bad rap, but what you smell post-workout is actually the odor of bacteria that is feeding on the components in your sweat. That’s right — in the same way that smelly gas coming out your backside is produced from bacteria fermenting food in your gut, odor is produced from bacteria feeding on sweat around your stinky areas, particularly the apocrine glands in places such as your underarms and crotch.

As you've probably experienced when you’re exercising hard, recovering from a workout, or perhaps “pitting out” from emotional stress, your body produces sweat to help you cool, as a “fight or flight” stress-response.

And this sweat is chock full of proteins, fatty acids, and a special kind of carbohydrate that bacteria absolutely love to eat. So to make energy and survive, the bacteria on your skin break down these components of sweat — and a byproduct of this bacterial metabolism is body odor.

Different bacteria produce different odors when they digest the components of your sweat, and because everybody has slightly different amounts of bacteria on their skin, some people smell better, worse, or simply different than others when they sweat.

In addition, your sweat tends churn out different kinds of proteins, fatty acids and carbohydrates based on the foods that you eat, so a particular diet may cause more or less body odor.

So how you can avoid stinking so much after your workout or when you’re stressed? Here are 4 tips:

  • Avoid sulfurous foods when you want to smell good. This includes foods such as meat, eggs, dairy, onions, garlic and even cruciferous vegetables such as broccoli. Coffee and alcohol can also tend to be stinky sweat culprits for many people.
  • Limit bacteria on the surface of your skin. I personally do this by showering with an anti-bacterial soap (Dr. Bronner’s) with oil of oregano added to the soap.
  • Use an underarm deodorant. Sadly, most deodorants create a chemical cocktail in your armpits, but here are a few good brands.
  • Season your food with cinnamon, cloves, nutmeg or cardamom. These spices tend to influence your sweat scent to a slightly more pleasant aroma.

Hopefully these tips help you, and the next time someone tells you “your sweat stinks,” just tell them it’s not your sweat, it’s those pesky bacteria.