Why Cold Plunges and Saunas Are Key to Marathon Recovery

May 28, 2025

Crossing that finish line is a moment you’ll never forget. The training, the miles, the early mornings—it all led to this. But once the medal’s around your neck and the adrenaline fades, one big question remains: How do you actually recover?

Because here’s the truth: running the race breaks your body down. What you do next is what builds it back up.

First Up: Get in the Plunge

We know the last thing your legs want after a marathon (or a 50-miler) is cold water. But hear us out. This is where recovery begins.

When you submerge in cold water (especially between 39-55°F), your blood vessels constrict, which helps reduce inflammation and minimize muscle micro-trauma from all those miles. This vasoconstriction is followed by vasodilation once you exit the plunge, encouraging fresh, oxygen-rich blood to flood your tissues, a powerful recovery mechanism.

It also helps flush out metabolic waste like lactic acid, which can build up during intense endurance events and contribute to delayed onset muscle soreness.

Mentally, cold plunging can activate the parasympathetic nervous system, your body’s rest-and-digest mode, helping to soothe your fried nerves and bring your cortisol levels down.

Post-plunge benefits:

Inflammation relief in legs, knees, ankles.
Boosted circulation and faster nutrient delivery to muscles.
Nervous system reset.
Mental clarity and emotional calm.

Then: Heat Things Up

After the cold, it’s time to melt into the sauna.

Using heat (180-220°F) increases your core temperature, which causes your blood vessels to dilate. This vasodilation boosts circulation, helping shuttle nutrients to your muscles and assisting with the removal of cellular debris.

Heat also stimulates heat shock proteins (HSPs) - molecules that help protect and repair muscle tissue under stress. Studies show that regular sauna use can enhance cardiovascular endurance, increase growth hormone levels, and even improve sleep quality, which is crucial post-race.

Post-run sauna benefits:

Accelerated muscle recovery and reduced stiffness.
Enhanced circulation and cellular cleanup.
Deep, restful sleep.
Calm mind and mood regulation.

Contrast Therapy: Cold + Heat = The Comeback Formula

Alternating between cold and heat, aka contrast therapy, taps into your body’s natural healing mechanisms. The temperature fluctuations create a pumping effect on the blood vessels, improving lymphatic drainage and speeding up waste removal.

Research has shown contrast therapy to be effective in:

Reducing muscle soreness and swelling
Improving range of motion
Enhancing recovery in endurance athletes

Protocols to Try

Beginner Protocol (Post-Race, First Time Doing Contrast)

3 minutes sauna (180-200°F)
1 minute plunge (50-55°F)
Repeat 2–3 rounds
End on cold

Why it works: Gentle introduction to thermal stress. Keeps your system responsive without overloading it.

Experienced Protocol (You’ve Done This Before)

10-15 minutes sauna (180-220°F)
2-3 minutes plunge (39-50°F)
Repeat 3-4 rounds
End on cold for alertness; end on heat if heading to bed

Why it works: Longer exposure promotes deeper adaptation, faster recovery, and stronger resilience.

Recovery Is a Skill

You trained hard for the race. Now it’s time to train your recovery - because real gains don’t just happen on race day. They happen in the hours and days after, when your body rebuilds, repairs, and levels up.

Whether it’s your first marathon or your tenth ultra, the Plunge and sauna are more than just tools - they’re your recovery team.