You should wash training kit at around 30°C on a cool, gentle cycle, because cool water cleans synthetic performance fabric fully while protecting the heat-sensitive elastane that gives it stretch and recovery. 30°C with a plain liquid detergent and no fabric softener is the setting that keeps technical kit performing and lasting; hotter washes shorten its life without cleaning any better.
- 30°C is the sweet spot: hot enough to lift sweat oils with the right detergent, cool enough to spare the elastane and heat-sealed seams.
- Heat, not water, degrades performance fabric; washing at 40°C or above accelerates elastane breakdown and can distort ultra-light race kit.
- THETA's Tech and Race lines blend polyester or polyamide with elastane and use heat-sealed construction, all of which reward a cool wash.
Why is 30°C the right temperature?
The odour and grime in training kit come from skin oils and bacteria, and those lift with a properly dosed detergent rather than with heat. At 30°C a plain liquid detergent has more than enough cleaning power for synthetics, so raising the temperature adds nothing on the cleaning side while adding real damage on the fabric side. Consider what that heat reaches on the THETA range: the elastane knitted through the shorts, tops and half tights for their 4-way stretch and snap-back relaxes and breaks down as the water warms, and the heat-sealed seams that replace bulky stitching are stressed by higher temperatures. 30°C is the setting that lifts the sweat oils while sparing exactly those two heat-sensitive features, which is why it is the recommendation for the whole line. Cool washing also uses less energy, which quietly lowers the running cost of maintaining a kit rotation.
What happens if you wash too hot?
Hot washing attacks the very features that make performance kit worth owning. Elastane loses its elasticity, so waistbands slacken and tops lose their fitted-chest shape after fewer washes. Ultra-light race fabric can set creases or distort, and heat-sealed pockets and fused seams, which rely on bonded material rather than stitching, can be stressed at higher temperatures. Hot water can also bake sweat oils deeper into the fibres, which is why some kit smells worse after a hot wash rather than better. In short, heat trades a small perceived deep clean for a measurable loss of lifespan and performance.
It helps to picture what elastane actually is. It is a fine elastomer filament twisted or knitted in among the polyester, and its whole job is to stretch and pull back to length thousands of times. That recovery is what stops a waistband bagging and holds a top fitted across the chest. Warm it repeatedly and the polymer chains relax a little further each time and recover a little less, so the fabric slowly forgets its shape. You do not see it in one wash. You see it as a shirt that used to sit close now hanging loose after a season of hot cycles. The heat-sealed seams tell the same story from a different angle: a fused bond is a strip of material melted and pressed into a join instead of a line of thread, chosen because it lies flat and does not chafe, and like any bond it softens as it warms. Neither feature announces its decline. Both simply arrive at the point of no return sooner if you keep pushing the temperature up.
Are there times to go warmer or cooler?
The temperature can flex slightly with the job, but the safe range stays narrow. Use this guide:
| Situation | Temperature | Notes |
|---|---|---|
| Everyday sweaty session | 30°C | Default; plain liquid detergent, no softener |
| Ultra-light race kit | 30°C, gentle, mesh bag | Gentlest handling; protect light seams and vents |
| Heavy odour or chalk | Cold pre-soak, then 30°C | Vinegar soak first; heat is not the answer |
| Non-technical cotton items | Up to 40°C | Only for garments with no elastane or ventilation |
Does temperature affect smell?
Many people wash hot hoping to kill odour, but that misreads the problem. Odour comes from oils and bacteria trapped in the fibres, and the reliable fix is a cool wash with the right detergent, plus a cold vinegar pre-soak for stubborn cases, not a hot cycle that can set the smell deeper. Prompt washing matters more than temperature: leaving damp kit in a bag lets bacteria multiply before the wash, so getting kit into a cool wash soon after training does more for freshness than turning up the heat. Drying fully and quickly afterwards, on a rack rather than in a hot dryer, completes the job.
How does temperature fit the wider care routine?
Temperature is one lever among several, and they work together. A 30°C wash only delivers its full benefit alongside a gentle cycle, plain liquid detergent, no softener, and air-drying, because a cool wash followed by a hot tumble-dry still cooks the elastane. It helps to picture the whole loop the way the kit was made: the race team knit, cut and heat-sealed these pieces, then wore and washed them across two seasons on the assumption of cool, gentle care, which is how the Tech and Race lines reach their two-plus years of hard use. Setting the machine to 30°C, then hanging kit up to dry, is the whole routine in two steps, and it is the cheapest way to protect a durable rotation. Get the temperature right and the rest of the care becomes easy.
What is the one mistake that undoes a cool wash?
Getting the temperature right and then tumble-drying on high. This is the most common way people cancel out their own good habit. A 30°C wash protects the elastane in the water, and then a hot dryer cooks it in the air, so the fabric never gets the cool treatment the setting was meant to give it. The dryer also tumbles vented, light kit against the drum and other zips, which stresses the very seams a cool wash was sparing. If you take one thing from this, let it be that the dryer undoes the wash. Set 30°C, then hang the kit up. The two steps belong together.
Watch too for the slow build of undissolved powder in a cool wash. Some powder detergents are formulated to dissolve fully only in warmer water, so at 30°C they can leave gritty residue that sits in seams and vents. A plain liquid detergent dissolves at low temperatures and rinses clean, which is why it pairs naturally with the cooler setting rather than working against it.
"Thirty degrees cleans training kit perfectly. People wash hot because they think it kills the smell, but heat just cooks the stretch out of good fabric. Cool wash, no softener, air-dry, and your kit lasts," says the THETA coaching team.
Common questions
Can I wash performance kit in cold water?
Yes. Cold water is safe and effective for synthetics when paired with a good liquid detergent, and it is ideal for pre-soaking smelly or chalky kit. A 30°C wash is marginally better at lifting oils in a single cycle, but cold works well for routine loads.
Does hot water clean sweaty kit better?
No. Sweat oils and bacteria lift with the right detergent, not with heat, and hot water can bake odour deeper into synthetic fibres. A cool wash plus a cold vinegar pre-soak for stubborn smells outperforms a hot cycle.
Will a cool wash kill bacteria in my kit?
A cool wash with proper detergent removes the oils bacteria feed on and flushes most of them out, which is what stops odour returning. Washing promptly after training and drying fully matters more for freshness than trying to sterilise kit with heat.
Does washing cooler save money?
Yes. Heating water is the biggest energy cost of a wash, so 30°C or cold cycles cut running costs, and they extend kit lifespan too. Cheaper to run and gentler on kit, cool washing is the better choice on both counts.
Sources
- THETA product construction notes and coaching data, 2024-2026
- Established textile-care principles (elastane heat sensitivity, detergent surfactant action, energy use)
- HYROX training and sweat-load context (hyrox.com)