How Often Should You Wash and Rewear Gym Clothes?

After returning from a run or a sweat-heavy gym workout, do you put your kit straight into the washing machine on a hot wash? Or does it end up on a chair - or in the ‘floordrobe’ - ready to be worn again the next day?

Earlier this year, French government guidance sparked debate by advising people on how frequently to wash their clothes. It suggests that sports clothes can be worn up to three times before washing.

The recommendation is rooted in valid environmental concerns: every wash cycle uses considerable amounts of water and energy. Washing garments too often can also wear out fabrics sooner, adding to textile waste.

Yet there is also the question of health. If the idea of putting a smelly T-shirt or damp sports bra back on makes you uncomfortable, here is what to consider.

Sports clothes and sweat

Exercise clothing was once generally made from natural fibres, chiefly cotton. Today, most activewear uses high-performance synthetic materials, designed to wick away moisture, regulate body temperature, increase breathability and reduce odours.

Nonetheless, studies have found that this type of workout clothing - especially synthetic fabrics - can contain substantial levels of bacteria after only one wear.

Polyester retains moisture, producing the warm and humid micro-environments in which bacteria thrive.

Bacteria reproduce far more rapidly when clothing is damp, including when it is wet with sweat. The more bacteria present, the stronger the odour tends to be.

Research also indicates that textile developments can make garments longer-lasting and more effective at limiting bacteria. These include silver nanoparticles incorporated into fibres, treatments based on essential oils, durable antimicrobial finishes and innovations in fibre structure.

Is it safe to rewear gym clothes?

The answer depends on a number of considerations:

Fabric type

Natural fibres, including cotton, encourage fewer odour-producing bacteria than synthetic materials. If you exercise in natural fabrics, you may therefore be able to wear them a few times before they need washing.

Exercise intensity and sweat level

Low-intensity exercise that results in little or no sweat, such as gentle yoga or walking, may make additional wears possible compared with high-intensity training. This is because bacterial growth is directly linked to the amount of moisture in fabric.

Indeed, the French government guidance notes that the frequency with which you wash sports clothes depends on how much you sweat.

Season

Climate conditions - including temperature, humidity and airflow - have a major influence on bacterial growth in textiles. It may therefore be more practical to wash clothes less often in colder months, when you are likely to sweat less.

Personal health

Certain people should take extra care when deciding whether to rewear gym clothes. This includes people with skin conditions, weakened immune systems or a tendency towards skin infections.

If you are wearing a cotton T-shirt and shorts for a light activity, such as a walk in the cool morning air, you may be able to wear them once or twice more - particularly if they are aired thoroughly between uses.

However, synthetic performance clothing, as well as anything worn for moderate or vigorous workouts, should be washed after every use. A cold wash cycle is sufficient. This matters particularly for garments that touch areas with high levels of bacteria, such as the underarms, groin and feet.

How to look after clothes between wears

1. Turn garments inside out, which exposes bacteria to the air, and hang them up as soon as you finish exercising.
2. Make sure every item is fully dry before putting it away.
3. Keep clothes in well-ventilated places, rather than enclosed spaces such as a laundry basket or bag.
4. Where possible, hang clothing in sunlight, as short exposure to UV light offers natural antimicrobial benefits.
5. Keep worn items separate from clean clothes.

The bottom line

Ultimately, the decision is personal: everyone must balance the environmental advantages against possible health concerns and their own exercise routines.

Some garments, however, should be washed after every use: sports bras and underwear, socks, anything that is visibly dirty or smells, and clothing worn during high-intensity exercise or in hot conditions.

Carolina Quintero Rodriguez, Senior Lecturer and Programme Manager, Bachelor of Fashion (Enterprise) programme, RMIT University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.