Woman stepping from a barrel sauna toward a wooden cold plunge tub on a deck, an H2Glow water bottle at her feet

Contrast therapy: sauna and cold plunge, in what order?

What is contrast therapy, and which comes first?

Contrast therapy means alternating heat and cold, such as a sauna and a cold plunge. After hard exercise, alternating warm and cold water eased soreness better than resting, but no better than other recovery methods. No study reviewed here tested whether hot or cold should come first, so the order is a preference, not a rule.

Part of the Glow Protocol guide. Start here: The Glow Protocol

Five things worth knowing

The best evidence is for sore muscles after exercise. It comes from studies of warm and cold water, not saunas.
Contrast beat resting. It did not clearly beat cold water alone, compression or stretching.
Order is untested. Hot first or cold first has not been compared in the research reviewed here.
Cold and heat each have their own evidence. Most of it comes from small studies.
Sauna sweat is real fluid loss. Replace the fluid and the sodium.

What the research on contrast therapy shows

The main source is a 2013 systematic review and meta-analysis of contrast water therapy after exercise that damages muscle. It found 18 trials, and rated all of them at high risk of bias.

Pooled data from 13 studies showed contrast water therapy improved muscle soreness more than passive recovery at every follow-up point, from under 6 hours to 96 hours.
It also reduced the loss of muscle strength at each of those points.
Compared with other methods, including cold water immersion, warm water immersion, compression, active recovery and stretching, there was little evidence that any one was superior.

The authors add that the size of these effects may matter most to elite athletes. Note what was tested: water baths after hard exercise. A sauna followed by a cold plunge for general wellbeing has not been tested in the same way.

Illustration of a block of skin split in two: under heat the blood vessels are wide and red, under cold they are narrow and blue — *Heat widens the skin's small blood vessels; cold narrows them. Illustration, not to scale.*

Does the order matter?

Nobody has shown that it does. The research reviewed for this page includes no trial comparing hot-first with cold-first, and none comparing ending on cold with ending warm. The contrast studies measured soreness after exercise, not sequence. Until someone tests it, choose the order you find easiest to repeat, and notice how you feel afterward.

One finding is worth knowing if you train afterward. In a 2023 meta-analysis of 20 studies, jump performance was lower immediately after cold water immersion. If you have a workout or a game straight after your session, ending on cold may not suit you.

The cold side: what cold plunges do

Soreness. A 2016 meta-analysis of nine randomized trials found cold water immersion slightly better than passive recovery for muscle soreness, both immediately and later.
Fatigue. The 2023 meta-analysis of 20 studies found cold immersion after exercise lowered soreness and perceived exertion straight away, and lowered the blood marker creatine kinase at 24 hours. It found no effect on two other blood markers, CRP and IL-6, over 48 hours.
Wellbeing. A 2025 meta-analysis of 11 studies and 3,177 healthy adults found stress was lower 12 hours after cold immersion, but not immediately, at 1 hour, 24 hours or 48 hours. Sleep quality and quality of life improved. Mood did not. Inflammation rose immediately and at 1 hour, which the authors describe as an acute inflammatory response. They also note the evidence is limited by few trials and small samples.

The hot side: what saunas do

After exercise. A 2025 systematic review of 14 studies and 194 participants looked at heat after exercise, including sauna and hot water. Of nine short-term studies, four found no effect on performance recovery, four found a benefit and one found harm. The authors could not draw firm conclusions.
Long-term health. In a study that followed 2,315 middle-aged Finnish men for about 20 years, more frequent sauna bathing was associated with lower risk of fatal heart disease and death from any cause. That is an association in one population, not proof of cause.
Skin. In 41 healthy volunteers, regular Finnish sauna users had a more stable skin barrier and higher water content in the outer skin layer than non-users.
Overall. A systematic review of 40 dry sauna studies found most reported benefits, but only 13 were randomized trials and most were small.

More: Infrared vs traditional sauna and Infrared sauna for skin.

How long and how cold should each round be?

The studies give ranges, not a recipe. For sore muscles, a meta-analysis of nine trials found the best results with cold water at 11 to 15°C (about 52 to 59°F) for 11 to 15 minutes. Wellbeing studies used 7 to 15°C for anywhere from 30 seconds to 2 hours. No ideal number of rounds has been established.

What	What the studies used	Source
Cold water for soreness	11–15°C (52–59°F), 11–15 minutes	Meta-analysis of 9 trials
Cold water for wellbeing	7–15°C (45–59°F), 30 seconds to 2 hours	Meta-analysis of 11 studies
Sauna, skin study	Two 15-minute rounds at 80°C (176°F)	Controlled study, 41 people
Sauna, heart-health cohort	Lower sudden cardiac death risk with sessions over 19 minutes than under 11	Cohort of 2,315 men

One caveat on temperature: the 2023 meta-analysis found that water temperature made no difference to fatigue recovery, so the "best" range above is not settled.

These are what researchers tested, not targets. If you are new to it, start shorter and milder and build up.

Is contrast therapy safe?

A review of sauna risks found sauna bathing is well tolerated by most healthy adults. It lists unstable angina, a recent heart attack and severe aortic stenosis as reasons not to use a sauna, and says alcohol during sauna bathing raises the risk of low blood pressure, irregular heartbeat and sudden death and should be avoided.

Cold water carries its own risks. A 2017 review of cold water immersion treats it as both a hazard and a treatment, and examines it as a precursor to drowning, cardiac arrest and hypothermia. It also found the evidence for some claimed benefits is still anecdotal.

Check with your doctor before starting contrast therapy, and before any cold plunge, if you have a heart condition, are pregnant or take medication that affects blood pressure. Do not plunge alone.

Replace what you sweat

A sauna makes you sweat, and that fluid has to come back. In one study, healthy young adults using a portable infrared sauna at about 66°C (151°F) lost more than 2% of their body mass in under 180 minutes. That protocol was designed to dehydrate people, so an ordinary session is likely to lose less, but the direction is the same.

A sports-science review found that to restore fluid balance after sweating, you need to drink more fluid than you lost and replace electrolytes, particularly sodium. Plain water covers the first part only.

More: What to drink after a sauna.

What contrast therapy does not do

It does not beat other recovery methods. It beat resting.
It does not "detox" you. A review of sweat physiology found the role of sweating in clearing waste and toxicants is minor compared with the kidneys and gut.
It has not been shown to build fitness. Repeated post-exercise heat had no effect on cycling performance or VO2max in the 2025 review, though it may help running in hot conditions.
It does not lift mood in the pooled data. The 2025 cold-water analysis found no significant effect on mood.

Make it a Glow Protocol

Before. Drink normally through the day so you arrive hydrated.
During. Follow the time and temperature guidance for your sauna and cold plunge, and get out if you feel dizzy or unwell.
After. Replace what you sweated out: more fluid than you lost, with sodium, through food or an electrolyte drink.
Daily. Skin hydration is built every day, not only on session days. That daily layer is Step 0.

H2Glow is Step 0: the hydration layer underneath the routine. It does not make any device work better. See the full Glow Protocol.

Where H2Glow fits

H2Glow's part is the sauna half. Sweat takes water and sodium with it, and both need replacing. One stick has 300 mg sodium, 200 mg potassium, 150 mg magnesium and 515 mg chloride. Mix it with water and keep drinking after it: the review above says to take in more fluid than you lost. H2Glow does not change what the heat or the cold does.

Frequently asked questions

Should you do sauna or cold plunge first?

No study reviewed here compared the two orders. Pick the sequence you will repeat, and consider ending warm if you plan to train right after.

Should you end on cold?

It has not been tested. Jump performance was lower immediately after cold immersion in one meta-analysis, which matters only if you are about to exercise.

How long should you stay in a cold plunge?

For muscle soreness, the best results in one meta-analysis came from 11 to 15 minutes at 11 to 15°C. Start shorter if you are new to it.

Does contrast therapy work?

After hard exercise, contrast water therapy reduced soreness and strength loss more than resting, across 13 pooled studies. It was not clearly better than other recovery methods.

Does a cold plunge help with stress or sleep?

A 2025 meta-analysis found lower stress 12 hours after cold immersion and better sleep quality, with no effect on mood. The authors call for more high-quality trials.

Can you use an infrared sauna for contrast therapy?

Yes, in the sense that it supplies the heat. The contrast studies used water, so there is no direct evidence for any type of sauna in this role.

Does sweating in a sauna remove toxins?

Very little. A review found sweat plays a minor role in clearing waste compared with the kidneys and gut.

What should you drink after contrast therapy?

More fluid than you sweated out, with sodium. See What to drink after a sauna.