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Fire and Ice: The Benefits of Contrast Therapy

Redwood Outdoors - Dec 8th 2022

Athletes have long known that extremes of temperature can aid recovery and keep them performing at their peak for longer. However, science has only recently begun investigating the best way to apply sweltering heat and frigid cold for maximum effect. Combining the two by alternating outdoor sauna heat and cold therapy is particularly effective and is known as contrast therapy, or “Fire and Ice” therapy. 

While you can obtain many benefits from both extremes, there are a few caveats about the order in which you should use them after exercise. 

Fire and Ice 

"Fire and ice" are polar opposites, but both high and low extremes shock our bodies into a physiological response. Although the two elicit different reactions from our systems, both come with distinct benefits and can be used to complement each other for post-exercise (or post-game) recovery. 

Indeed, some researchers' findings show it is a mistake to default to only using one therapeutic method, as your body gets used to that approach and stops responding so well, whereas switching it up keeps your recovery dynamic. 

You can (and should) incorporate these thermal modalities into your daily routine, as you reap many benefits primarily from ongoing, long-term use. 


Heat therapy from saunas, whether an indoor sauna or outdoor sauna, stimulates blood flow to the body's surface, carrying toxins such as the heavy metals lead, zinc, mercury, and cadmium to the skin, whence they can be eliminated. As a result, the toxic burden on your nervous system, endocrine system, and liver is reduced. 

The increased circulation also helps remove lactic acid, formed during intense anaerobic activity, from the muscles, reducing post-workout stiffness. 

High temperatures trigger anti-inflammatory responses, stimulate the body's production of internal antioxidant compounds that scavenge the free radicals produced by exercise, and up-regulate the expression of heat shock proteins, which increase white blood cells in the long term, enhance your muscles' growth, and reduce inflammation in your brain. 

Heat also changes your body's "engines" and fuel supply: getting into a barrel sauna regularly stimulates your muscle cells to make more mitochondria, the organelles that burn glucose for energy. Moreover, your body's ability to turn the glycogen stored in your muscles into glucose your mitochondria can use as fuel improves. 

You can also promote beneficial gene expression after strength-based activities, such as weight-lifting, by treating your body to heat inside a barrel sauna. If you use your outdoor sauna regularly after pushing the force-producing abilities of your muscles, you will switch on "good" genes and switch off "bad" genes, which has a long-term impact on your health. 

Don't forget the role of quality sleep in maintaining your health and helping your body recover from physical stress, such as exercise. Spending time in a barrel sauna temporarily boosts your core body temperature, after which it drops by 2 to 3 degrees - this drop in core temperature helps you get to sleep faster and rest more soundly. 

The high temperatures of a sauna stimulate the sympathetic nervous system and promote endorphin release, both of which ease the pain induced by a workout or competition. 

However, there's an essential tip about heat therapy: don't get into a hot sauna immediately after exercise, and don't use a heating pad. Applying heat directly after exercise exacerbates the inflammation that sets in as the secondary damage phase takes hold. Instead, take an ice bath first. 


Cooling your body down causes superficial blood vessels to constrict as more blood goes to your core. The reduced blood flow to your muscles slows down their metabolism and diminishes the inflammatory response during the secondary damage phase (which can last 24 to 72 hours after exercise). The best time to use cold therapy is immediately after your workout. 

A post-workout ice bath reduces pain and swelling in your muscles and lessens delayed-onset muscle fatigue, which, as the name suggests, only shows up later. 

After applying cold therapy following a workout, follow up with warmth to ward off joint stiffness and muscle spasms and diminish pain. As you see, sequencing cold therapy and heat therapy in the correct order following strenuous activity produces optimal recovery. 

Exposing your body to frigid temperatures by taking ice baths induces the production of "cold shock" proteins that help protect against dementia and up-regulate your immune system function. While moderate exercise is good for your immune system, elite athletes often have suppressed immunity, so it makes sense to counteract this. 

A cold plunge into icy water after endurance-dominant exercise such as long-distance running encourages advantageous gene expression. As with heat treatment, you should make ice baths a regular practice to reap the full epigenetic benefits and resulting long-term health benefits. Using a plunge tub to take an ice bath allows you to have it in the yard, next to your sauna. 

Benefits of Alternating Sauna and Cold Plunge 

In Finland, where the sauna originated, people often built them next to one of the myriad small lakes dotting the Finnish landscape. They would follow a sauna session by jumping into the lake to cool off or rolling in powder snow during the winter! Other Nordic countries and neighbors like the Russians have similar traditions. 

But why would you want to get warm in a sauna and then shock your body with a cold plunge into the icy water? Or even go through the cycle multiple times, as some people do? 

One reason is that the poles of the cycle have a synergistic effect. The practice of alternating heat and cold is known as contrast therapy, and it works better than either approach does on its own. Sports scientists are still researching how much of an edge it will give you. 

2021 study published in Cell Reports Medicine found improved brown adipose tissue (BAT) activity and enhanced thermoregulation in a group of young men who followed the Nordic cultural tradition of winter swimming and sauna alternation. As a result, they burned more calories at low temperatures and were at lower risk of metabolic disease. 

The thermal shock of going from a hot sauna into frigid water triggers a flood of adrenalin through your body, pushing you into fight-or-flight mode. When you first experience this, you will find it stressful. But you will find it beneficial in the long term. 

Repeated exposure to the stress of icy water results in you handling it better, which leads to an enhanced ability to deal with everyday stressors. Moreover, over time, you will find the sudden thermal shock lifting your mood and pushing you into a state of heightened alertness. Both effects improve your mental health. 

If you don't have a convenient lake by your outdoor sauna, consider installing a plunge tub to reap the benefits of a cold plunge. 

Final Thoughts 

Saunas and plunge tubs allow athletes to practice contrast therapy. This “fire and ice" treatment modality reduces recovery time, enhances post-workout gains as the body repairs itself, and yields long-term benefits ranging from advantageous gene expression to improved ability to handle stress.