Ice Baths

Cold water immersion is among the most studied recovery practices available, and the findings are unusually specific about temperature and duration.

Alertness and mood. Cold water triggers a large release of noradrenaline, the neurotransmitter behind alertness, focus and attention. In protocols resembling normal use, 20 seconds at 4 degrees, three times a week for twelve weeks, plasma noradrenaline rose 200 to 300 percent above baseline. Under a far more demanding protocol, a full hour at 14 degrees, one study recorded a 530 percent increase in noradrenaline alongside a 250 percent increase in dopamine. Elevations of this kind persist for hours rather than minutes, which is why people describe a sustained mental clarity through the morning after an early plunge.

Muscle soreness and recovery. A network meta-analysis examining different combinations of temperature and duration found the strongest results from 10 to 15 minutes at 11 to 15 degrees. That combination significantly reduced delayed onset muscle soreness, significantly reduced creatine kinase, a blood marker of muscle damage, and significantly improved jump performance in the days following hard exercise. Colder water at 5 to 10 degrees for the same duration also produced significant results, but was not superior.

That is a useful finding, because it says the temperature most people can actually tolerate is the one the evidence supports. Colder is harder, not better.

Metabolic response. One hour at 14 degrees raised resting metabolic rate by 350 percent during immersion. At 20 degrees the increase was 93 percent. These are acute responses during exposure rather than a sustained change.

Sleep. Core temperature drops after immersion and then rebounds, and that rebound forms part of the same thermal signal that supports deep sleep.

Every study referenced here is cited in full in our research library.

The research points to two different protocols depending on what you want, and they are not the same.

For alertness, mood and the mental side. Short and cold. Two to five minutes at 3 to 10 degrees. This is the morning session, and it is where the noradrenaline response sits.

For muscle recovery after hard training. Longer and less extreme. 10 to 15 minutes at 11 to 15 degrees, which is what the meta-analysis found most effective for soreness, muscle damage markers and jump performance. Colder was not better.

This is where set and forget temperature control earns its place. Running both protocols from the same bath means changing the temperature depending on the day, which is straightforward with a chiller and effectively impossible with ice.

One caveat that matters. If maximum muscle growth from resistance training is your primary goal, avoid plunging within an hour of lifting. Cold immersion appears to blunt some of the adaptive signalling that drives hypertrophy. This does not apply to endurance training, and it does not apply if you plunge at a different time of day.

The chiller is what turns cold water from an occasional effort into a routine.

Without one, a bath is filled with ice before every session. Three bags a session, four sessions a week, comes to more than six hundred bags and around two hundred trips across a year, before accounting for the fuel, the time and the temperature you cannot control.

The Emerge Chiller holds whatever temperature you set, continuously. The Circular maintains it to within 0.3 of a degree. Cooling ambient water to plunge temperature takes approximately five hours, after which it simply holds. Replace the cover when you finish and the bath is ready the following morning at the temperature you chose.

Running costs are modest. Holding water at 10 to 12 degrees draws roughly 0.3 to 0.5kW, which is in the order of 10 to 15 cents an hour depending on your tariff and the weather.

The chiller is included with the Circular and the Timber, and is built into the All-In-One. It is not a separate purchase.

Precision temperature control applies at both ends of the range. The Emerge range runs from 3 degrees to 42, set from the digital panel or from your phone.

At 3 to 6 degrees you have a serious plunge for anyone who has built the tolerance. At 10 to 15 degrees you are in the range most of the research used, which suits most people. At 15 to 20 degrees you have a cool immersion that remains manageable through a Melbourne winter.

At the upper end of the range you have warm water. A hot immersion before bed, or a warm bath for the household on a cold evening, using the same unit you plunged in that morning. Contrast bathing without owning two things.

Check the specification for your model. Temperature range and precision vary across the range and each product page states its own.

Emerge Circular Ice Bath, $4,895
900 x 900 x 1100mm, 477 litres, 316 marine grade stainless steel. The one that fits where nothing else will: a corner, a side passage, a small deck. You step in from any angle rather than climbing in from one end. 3 to 42 degrees held to within 0.3 of a degree, runs at 45 to 52 decibels, and connects to WiFi for remote scheduling. Chiller included.

Emerge Timber Ice Bath, $5,695
1300 x 900 x 700mm, 346 litres. Stainless steel interior with Canadian red cedar cladding and steel banding. Full length, so you lie back rather than sit up. The cedar needs one coat of food safe oil a year and improves with age. Ships with a universal wheel, cover and step. Chiller included.

Emerge All-In-One Ice Bath, $8,999
1900 x 780 x 890mm, 524 litres, marine grade stainless steel throughout. The chiller, filtration and controls are built into the housing, so there is no second unit on your deck and no hose running across the pavers. 3 to 42 degrees from the panel or your phone. The largest volume in the range and the one to buy if you want it to look like a single considered piece of equipment rather than a kit.

Emerge Chiller, $2,400
Included with the Circular and the Timber when you buy them together. Sold on its own for anyone who already owns a bath and is finished with ice. Holds any temperature from 3 to 42 degrees continuously, connects by hose, wheeled housing so you can position it yourself, and plugs into an ordinary power point.

Not sure which suits your space? Talk to us. Access and placement are usually the deciding factors.

316 marine grade stainless steel. The grade specified for marine fittings and outdoor architectural work. It handles UV, coastal air and humidity year round without seasonal storage, and it will not stain, sag or perish the way a lined tub can.

The chiller is included in the price. Worth checking when comparing. A lower advertised price often covers the tub alone, with temperature control quoted separately.

Repeatable temperature. Within 0.3 of a degree on the Circular, anywhere from 3 degrees to 42. If you are following a protocol, the temperature in the research needs to be the temperature in the water.

No electrical work. The chiller runs from an ordinary 10 amp power point using the supplied cord. A dedicated circuit is recommended for consistent running, but no electrician is required.

Free East Coast Metro Delivery and a 7 year warranty on the bath, with 12 months on the chiller. Full terms are on our **warranty page**.

Pairs with heat. Contrast bathing is the oldest recovery protocol there is. See the sauna range or build the pair together.

Cold water immersion places a genuine physiological load on the body, which is the point of it, and it warrants some care.

Start at two minutes and build from there. Ten to fifteen degrees is the range most of the research used. Colder is not better, only harder. If you are new to it, do not plunge alone, and get out if you begin shivering uncontrollably or lose sensation in your hands or feet.

Speak with your doctor before starting cold water immersion if you have a cardiovascular condition, high blood pressure, Raynaud's, or if you are pregnant. If you are on medication that affects heart rate or circulation, ask first.

There is more detail on protocol, timing and dose in the FAQs below, and our ice bath guide covers easing in, timing and temperature in full.

Delivery. Free East Coast Metro Delivery. We deliver the bath to your address. Unpacking, positioning and assembly are arranged by you, so please have help on hand. These are heavy units, 142kg for the Circular, 150kg for the Timber and 220kg for the All-In-One. Outside East Coast Metro, contact us for a quote.

Where it goes. A flat, level, load rated surface. A deck, pavers or a concrete pad. Allow roughly 2m x 1m for the All-In-One plus half a metre each side to get in and out comfortably. The Circular needs far less, which is the reason it exists.

Power. An ordinary power point within reach. No electrician required.

One suggestion. Position it out of direct sun where possible. Shade reduces the work the chiller does and the running cost with it.