Protocols

Pick a number: the temperature guide for every audience

"How cold should it be?" is the most asked question at every handover. The honest answer: it depends who is getting in and why - and the research is more moderate than the influencers. Set points, times and rules, by audience.

Protocol guide · 2026-09-01

One law before the table: evidence over ego. The meta-analytic sweet spot for post-exercise soreness is 11-15 °C for 11-15 minutes (Machado et al., Sports Medicine 2016) - accumulated, not endured in one sitting. The famous neurochemical study used a civilised 14 °C (dopamine +250%, Sramek 2000). Sub-5 °C bravado belongs to experienced users making an informed choice, not to your reception desk defaults.

Set points by audience

Audience	Set point	Time	Notes
First-timers, hotel guests	12-15 °C	1-2 min	host present, breathe first
Regular members	10-12 °C	2-3 min	the habit zone
Trained athletes	8-10 °C	3-5 min	post-conditioning days
Experienced cold users	5-8 °C	2-3 min	opt-in, posted rules
Contrast circuits	10-12 °C	1-3 min × rounds	with 85-95 °C sauna
45+ / mixed club members	12-15 °C	1-2 min	graded entry, rails

Commercial reality check: the colder the set point, the longer each guest's tolerable dip - but the slower your queue and the higher your power bill. Most venues land at 8-12 °C: cold enough for the gasp, warm enough for throughput.

The physics of holding those numbers here

Tropical lowland air sits at 28-34 °C, so every degree below ambient is machinery: a 400 L lidded tub in Jakarta leaks roughly 516 W at 5 °C - which is why it wants a 2 HP chiller, holds ±0.3 °C once there, and costs about Rp 214 ribu/month to keep cold. The chill-down itself (29→5 °C) takes ~5.4 hours; daily operation just holds. Lids halve the bill; shade helps; insulated shells make the difference between a set point and a suggestion.

House rules we post at every commercial zone

Rinse before entry - hygiene starts upstream of filtration.
Never alone: commercial cold is a supervised or buddy activity.
Breathe before, not through: settle breath at the edge, enter on a long exhale, no breath-hold contests.
Contraindications posted: cardiovascular conditions, pregnancy, and anything a doctor should clear first - we are builders, not physicians.
Timers visible: a clock on the wall beats bravado in the water.

Audience protocols become products quickly: beginner slots at 12 °C, athlete hours at 8 °C, one tub, one schedule. The venue playbooks live on the sector pages - gyms, hotels, padel.

Can one tub serve beginners and athletes?

Yes, by schedule: run 12 °C days with 8 °C athlete windows. Set point changes take effect within the hour at typical volumes.

Is 3 °C ever the right call?

It is the coldest we hold, and some experienced users want exactly that. As a venue default - no; as an opt-in expert setting with posted rules - fine.

Do lids matter that much?

Yes: an insulated lid roughly halves standing losses. It is standard on our commercial units for the electricity bill alone.

What about warm plunges for contrast?

The same chiller heats to 40 °C - one machine can run a cold tub in the morning and a warm soak for evening circuits. See contrast therapy sets.

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