Home>Health and Wellness>Health>Do Gym Shorts Smell? – An Olfactory Expedition into the World of Running Shorts

Do Gym Shorts Smell? – An Olfactory Expedition into the World of Running Shorts Do Gym Shorts Smell? – An Olfactory Expedition into the World of Running Shorts


Do Gym Shorts Smell? – An Olfactory Expedition into the World of Running Shorts

Gain insights into the importance of hygiene and ventilation in keeping gym shorts fresh and odor-free. With this guide, you'll gain a better understanding of how to maintain fresh-smelling gym shorts, allowing you to stay confident and comfortable during your workouts.

Running is a liberating, exhilarating activity, a primal motion that speaks to our very core. As we pound the pavement or conquer the treadmill, there is a single unassuming item that’s always there with us – our running shorts. This humble piece of cloth, light and flexible, plays a critical role in our athletic pursuits. But there is one question that has probably crossed our minds at some point – do gym shorts smell?

Let’s embark on a comprehensive exploration of this topic and demystify the olfactory aspects of running shorts.

The Science of Sweat

To understand why running shorts might smell, it’s essential to delve into the science of sweat. Our bodies produce sweat as a natural cooling mechanism during exercise. The sweat itself is virtually odorless, but the story changes once it mixes with bacteria on our skin.

  • Bacteria & Sweat: The bacteria on our skin break down the sweat, particularly the fatty acids and proteins in it. This decomposition process leads to the production of various compounds, the most prominent being isovaleric acid and propionic acid. These compounds are the main culprits behind that notorious ‘gym clothes’ smell.
  • Types of Sweat: We produce two types of sweat, eccrine and apocrine. Eccrine sweat, produced all over the body, is mostly water and salt. Apocrine sweat, on the other hand, is secreted in areas like the armpits and groin. It’s richer in proteins and fats, making it a delicious feast for bacteria.
  • Synthetic vs. Natural Materials: Synthetic materials, such as polyester, used in many running shorts, are not very good at absorbing sweat, creating a wet environment that bacteria love. On the contrary, natural materials like cotton absorb sweat better, reducing the potential for bacteria growth.

The Materials Matter

As we’ve seen, the materials used in your running shorts significantly influence whether or not they smell after a run. But what materials are we talking about exactly?

Synthetic Materials

  • Polyester: This is the most common material used in running shorts. Polyester is lightweight, durable, and quick-drying, making it an excellent choice for athletic wear. However, its downside is its poor absorption capability. This leaves sweat on your skin and shorts, creating an environment conducive to bacterial growth.
  • Nylon: Another common choice, nylon is highly durable and somewhat better at wicking moisture than polyester. However, it still lags behind natural fibers in sweat absorption.
  • Spandex: Spandex is renowned for its excellent elasticity and often blended with other materials to add stretch. Like polyester and nylon, it struggles to absorb sweat effectively.

Natural Materials

  • Cotton: Cotton is a natural fiber that is excellent at absorbing sweat. It can help keep the skin dry and reduce the possibility of bacteria multiplying. However, its downside is that it becomes heavy and uncomfortable when wet and takes a long time to dry.

Blended Materials

Manufacturers often blend different materials to get the best of both worlds. A common blend is cotton and polyester, providing the moisture-wicking capability of cotton with the durability and quick-drying nature of polyester.

How to Prevent Gym Shorts from Smelling

Understanding why gym shorts smell is one thing; learning how to prevent it is another. Here are some practical tips to keep your running shorts fresh and odor-free.

  • Wash them immediately: The longer you leave your shorts after a workout, the more time you’re giving bacteria to break down the sweat and create those unpleasant smells. Try to wash your shorts as soon as possible after your run.
  • Use a sports detergent: Regular detergents may not be enough to deal with the smell-causing bacteria. Sports detergents are specifically formulated to tackle these bacteria, ensuring your shorts come out of the wash smelling fresh.
  • Air them out: If you can’t wash your shorts immediately after your workout, at least try to air them out. Leaving them crumpled in a gym bag creates the perfect warm, moist environment for bacteria to thrive.
  • Consider natural or blended materials: While synthetic materials are popular for running shorts, if you’re having issues with odor, consider trying shorts made of natural or blended materials.


So, do gym shorts smell? Yes, they can, but it’s not inevitable. The smell is primarily a result of bacteria breaking down sweat, and this can be exacerbated by the synthetic materials used in many running shorts. But by understanding the science behind the smell and following our practical tips, you can keep your running shorts fresh and odor-free.


Why do my running shorts smell even after washing?

This can occur if your detergent isn’t effectively eliminating the bacteria on the shorts. Try using a sports detergent, which is specially formulated for gym clothes.

Can the smell of gym shorts cause skin infections?

The smell itself won’t cause skin infections, but the bacteria causing the smell can, especially in damp and warm conditions. Ensure you clean your shorts regularly and properly.

Do all materials used in running shorts smell?

Not necessarily. Smell is often more associated with synthetic materials like polyester and nylon because they’re not as good at absorbing sweat compared to natural fibers like cotton. However, even cotton shorts can smell if not washed regularly.

How can I make my running shorts smell better?

Washing your shorts immediately after a workout, using a sports detergent, airing them out if immediate washing isn’t possible, and considering natural or blended materials can all help make your running shorts smell better.

Can the type of sweat affect the smell of my running shorts?

Apocrine sweat, which is rich in proteins and fats, provides a feast for bacteria, leading to a stronger smell compared to eccrine sweat, which is mostly water and salt.