If you run cold before a HYROX start, wear a removable warm layer over your race kit, such as a hoodie or quarter-zip, that you strip off just before the gun, leaving a light synthetic singlet or tee underneath. As of 2026, the goal is to stay warm through the long wait and warm-up, then race in minimal kit that sheds heat once you are moving.
- HYROX athletes often wait in warm-up pens and holding areas for a long time before their heat starts.
- The race itself, 8 runs and 8 stations, generates enormous heat, so you overdress at your peril.
- A layering system separates the pre-start warmth problem from the in-race cooling problem.
Why do you feel cold before the start but hot during?
You might reasonably object that if you are shivering in the pen, surely you should race in something warm. That instinct is exactly what catches people out. Before the start your body is doing almost no work, standing around, nervous, blood pooling, in a possibly cool holding area, so you cool fast. Once the gun goes, working muscles produce heat within minutes and your core temperature climbs. Dress for the cold you feel now and that kit becomes a heat trap the moment you run. The honest answer is that the pre-start chill and the in-race heat are two different problems, and one garment cannot solve both.
What should the layers be?
Build from the skin outward. Your base and race layer is a light synthetic singlet or technical tee, the piece you will actually race in. Over that goes a warm, easily removable top such as a Thermo Hoodie or an Element quarter-zip, worn through the warm-up and stripped before your heat. THETA's quarter-zip includes a protective zip cover and 4-way stretch, so it moves during warm-up drills and comes off cleanly. Trackies or joggers over your race shorts keep the legs warm and pull off over trainers thanks to zipped ankle cuffs.
How do you time the layer removal?
Warmth is only useful up to the moment you start producing your own heat. Follow a simple sequence:
- Keep all layers on through the queue and the early, easy part of your warm-up.
- Do a proper active warm-up, runs and drills, so you reach the line already warm, not cold.
- Strip the hoodie or quarter-zip and trackies in the final few minutes before your heat.
- Hand layers to a supporter or leave them in your allocated bag drop, not on the floor.
- Start the race in your light race kit, slightly cool, knowing you will heat up within the first run.
| Layer | Piece | Role | When it comes off |
|---|---|---|---|
| Race layer | Race Singlet or Tech Tee | What you race in | Stays on |
| Warm top | Thermo Hoodie / quarter-zip | Warmth in the pen | Just before the heat |
| Legs | Trackies with zip cuffs | Keep legs warm | Just before the heat |
| Feet | Old trainers or slides | Warmth pre-race | Swap to race shoes |
Should you warm up harder if you run cold?
Here is where clothing hits its limit, and it is worth being honest about it: no layer fixes a cold, stiff body. The most reliable way to stop feeling cold at the line is to generate your own heat with a thorough active warm-up, not to add another top. An athlete who has not warmed up will run the first kilometre stiff and inefficient, which costs more than any garment saves. Aim to arrive at the line warm from movement, dressed in light race kit, so your body is ready to work. The layers do only one job, holding that warm-up heat in until the gun.
"Dress for the race you are about to run, not the queue you are standing in. Warm up properly, peel the layers, and start slightly cool. You will be hot within one kilometre," says the THETA coaching team.
What about between the warm-up and the pen?
The one gap layering does not automatically cover is the awkward wait between finishing your warm-up and your heat being called, and this is where cold-runners quietly lose everything they built. A quarter-zip with a protective zip cover or a brushed-interior Thermo Hoodie holds heat cheaply through that wait, and both come off in seconds. Keep moving gently, stay in your warm layers until the last moment, and only expose your race kit once you are about to enter the corral. Skip that and the warm-up you worked for drains away standing still.
Common questions
What should I wear if I get cold before a HYROX?
Wear your light race kit underneath, with a removable warm layer such as a hoodie or quarter-zip and trackies over the top. Keep them on through the wait and warm-up, then strip to race kit just before your heat starts.
Won't I be cold at the start line in just a singlet?
Slightly, and that is correct. Your body produces heat fast once you start running, so you should feel a little cool at the line. A thorough warm-up beforehand means you start warm, not cold.
Can I race in a hoodie if I run cold?
No. A hoodie traps heat and becomes a soaked, heavy burden within minutes of racing. Use it for warmth before the start only, then remove it.
What do I do with my warm layers during the race?
Hand them to a supporter or use the event bag drop. Do not leave kit on the floor of the corral where it can be lost or in the way.
Should I wear trackies or shorts to warm up in?
Warm up in trackies over your race shorts, ideally with zipped ankle cuffs so they pull off over your trainers. Remove them with your top layer just before the heat.
Does a proper warm-up really replace extra clothing?
Largely, yes. Generating heat through running and drills warms you more reliably than clothing and also prepares your muscles for the opening kilometre. Clothing simply preserves that heat until you start.
Sources
- HYROX official race-day format and start procedures (hyrox.com)
- THETA coaching data, 2024–2026
- Established principles of warm-up, thermoregulation and race-start readiness
Need a warm layer that strips off clean at the line? THETA's hoodies, quarter-zips and trackies pair with light race kit so you stay warm in the pen and cool on the course. Explore the THETA performance kit.