When to Use Cold vs Heat for Training and Recovery

Both cold exposure (ice baths) and heat therapy (steam sauna, hot tub, or hot-water immersion) are powerful tools to complement your training routine. But knowing when and why to use each makes all the difference.

Quick intro to each practice

Cold-plunging involves immersing your body — partially or fully — in very cold water for a short period. To qualify as cryotherapy, water should be below 13°C and sessions typically last 2–3 minutes (up to a maximum of 8 minutes).

Wet saunas (not dry sauna) use steam to generate intense heat with nearly 100% humidity, typically between 40–55°C.

And of course, hot-water immersion / jacuzzi — usually above 35°C — is an often underrated tool for recovery.

Cold or Heat Before Training?

Cold-plunging

Cold immersion before training can boost performance.

Nicolás Ini, biohacker and founder of Tuluka, explains: “When we do an ice bath, we lower our core temperature and start from a cooler baseline.”

This means you reach the point where your body overheats much later, helping you go harder for longer.

Other benefits of pre-training cold exposure:

Energy and adrenaline boost
Increased blood flow
Improved range of motion
Higher oxygen availability

So, cold-plunging before training is a good idea.

Recommendation: cold-plunge 1–2 hours before training so your body has time to re-warm.

Sauna or hot immersions

Heat before training is not recommended. It puts your body in a deep relaxation mode, not ideal for peak performance. Like we say… heat before training leaves you melty and sluggish.

It may also increase dehydration risk if you combine sauna with exercise.

Hot or Cold Post-Workout?

Cold-Plunge

Taking the plunge after training will depend on your goals.

If your goal is muscle growth (hypertrophy), avoid cold immersion right after lifting since it can reduce muscle growth by over 60% (Betz et al., 2025).

After heavy training, the body begins repairing micro-tears in muscle fibers to build new tissue. If you take a cold plunge in the middle of this process, muscle growth will be stopped.

Rule: wait 6–8 hours after training before doing a cold plunge if you’re focused on building muscle.

Now, if your goal is faster recovery, feeling like your best, then ice baths are your way to go.

After an intense workout or high-frequency training, lactic acid goes up and causes muscle pain and fatigue. Cold-plunging can help lower lactic acid and boost anti-inflammatory proteins in the blood, easing muscle soreness and speeding up recovery.

Sauna

Post-training sauna is recommended. Why?

Does not hinder muscle growth — actually supports it thanks to the boost in growth hormone (helps protect and grow muscle).
Relaxes stiff muscles
Improves blood flow and recovery

Tip: wait 15–30 minutes after your workout, hydrate, then sauna.

Hot water immersion

Just 10 minutes in hot water after training can: increase strength, improve recovery and accelerate adaptation.

In this study, two groups of athletes followed the same training protocol: high-intensity leg sessions over two weeks. Both groups finished with heat exposure, but the method was different:

One group did a 10-minute hot-water immersion (bathtub) at 40 °C.
The other group took hot showers at the same temperature.

And the results are very interesting: the immersion group saw a 9.3% increase in maximum leg strength. The shower group? Only 4.5%. Same training. Same temperature. Different heat method.

Hot-water immersion activates heat-shock proteins, which help the body repair damaged muscle fibers and strengthen the signals that drive adaptation.

Hot-water immersion also helped reduce leg muscle fatigue and boost blood circulation.

Another plus: neither group experienced negative changes in cardiovascular function, indicating that short-term resistance training combined with hot-water immersion/showers was safe for the heart.

(*) Important note: This information is educational. Always consult a health professional before adopting these practices.

Explore your full potential and experience the benefits Alfa Humans can bring to your life. Learn more about our Cold & Hot Baths and portable steam saunas.