While research on cold exposure in humans still emerging, some evidence suggests that when implemented properly, it can improve well-being and even reduce depressive symptoms. Cold exposure activates cold shock proteins, which preliminary studies indicate could have therapeutic benefits for neurodegenerative diseases.
 

The Good News: Cold Exposure for Cognitive Enhancement

The benefits of cold exposure are accessible and straightforward. It’s low cost, simple, and quick to perform — just 20 seconds at 40℉ or 5–15 minutes at 50–55℉ can enhance cognition and mood. This makes it a viable option for nearly anyone interested in trying it as long as one can perform it safely.
 

From my own experience, I’m convinced that the neuroendocrine benefits of intermittent cold exposure are real and powerful. After a brief session in the cold plunge, I feel more awake and alert throughout the day.
 

The Bad News: Cold Exposure Might Be Sabotaging Your Muscle Gains

While cold exposure can boost your brainpower, it might be compromising your muscle-building efforts. Like all tools, cold water immersion serves a specific purpose and may be less effective — or even counterproductive — if used at the wrong time.
 

Initially, cold water immersion gained popularity among athletes for its ability to improve recovery by reducing inflammation, muscle damage, and soreness. It’s very effective in this regard. When used after exercise, cold water immersion reduces delayed-onset muscle soreness (DOMS), lowers markers of muscle damage and inflammation, and accelerates fatigue recovery — allowing athletes to bounce back faster for the next training session.
 

But this quicker recovery could come at a cost.

The Muscle-Blocking Effects of Cold Exposure

Recent evidence suggests that cold water immersion immediately after resistance exercise reduces gains in muscle strength and size. A 2024 meta-analysis by Dr. Brad Schoenfeld and colleagues concluded that combining cold water immersion with resistance training leads to less hypertrophy compared to the same training performed without it. Although the effects are small, they are notable. However, due to the low quality of studies included, the authors were cautious about making broad recommendations.
 

Another meta-analysis from 2022 found that post-exercise cold water immersion reduced strength gains during resistance training.
 

So, should you avoid cold water immersion after exercise if you're aiming for muscle gains? It seems that avoiding it right after your workout is wise, especially if long-term adaptations are your goal.
 

Why Does Cold Exposure Inhibit Muscle Growth?

In my interview with Dr. Luc van Loon in episode 93 of the FoundMyFitness podcast, he provided insights into the mechanisms behind these effects, which you can hear about in the clip below. Be sure to subscribe to the FoundMyFitness Clips channel to stay up to date with the latest content!

When you immerse in cold water after exercise, muscle blood flow decreases — heat enhances muscle blood flow, while cold reduces it. This reduced blood flow is similar to why icing an injury was once recommended to reduce swelling, though this practice is now less common.

Cold exposure also decreases muscle protein synthesis — the anabolic process that signals for our muscles to grow. After exercise, muscle protein synthesis naturally increases, especially when protein is consumed. However, cold exposure blunts this increase, even when protein is taken within the so-called “anabolic window” post-exercise.

These are acute effects, reflecting very short-term changes in protein synthesis (1–2 hours) after exercise. But would these effects persist over longer periods?

Postexercise cooling impairs muscle protein synthesis rates in recreational athletes. J Physiol. 2020

Indeed, regularly applying cold water immersion during two weeks of resistance training results in lower daily muscle protein synthesis. This likely leads to reduced muscle conditioning — less strength and hypertrophy — over time. Moreover, other anabolic pathways, including the activation of key proteins and satellite cells, are diminished after cold water immersion compared to active recovery like low-intensity cycling.
 

How cold and how long does cold exposure need to be? Just 10–15 minutes of cold exposure at 8–15℃ (46–59℉) is enough to exert these muscle-mitigating effects based on the most up-to-date research.
 

So, is there a way to enjoy the neurocognitive benefits of cold exposure without sacrificing muscle gains?
 

Striking a Balance: Reaping the Benefits of Cold Without the Costs

This is exactly what I asked Dr. Luc van Loon, and he offered some insightful alternatives:
 

Cold Showers: Taking a cold shower is unlikely to have the same muscle-mitigating effects as whole-body cold water immersion but can still provide mood- and alertness-boosting benefits, albeit to a lesser degree.

Timing Matters: Avoid cold exposure during the first few hours after exercise, as this is a crucial period for anabolic signaling. Waiting 6–8 hours or more after your workout may reduce the negative effects on muscle gains. To be extra cautious, consider doing cold exposure on non-training days.
 

Does Cold Exposure Affect Endurance Training?

Dr. Luc van Loon speculates that cold water immersion might negatively impact endurance training adaptations in a similar way to strength training, as protein synthesis is crucial for both. However, the evidence isn’t settled. Some studies indicate no adverse effects of cold water immersion after endurance exercise, and some even suggest positive outcomes like enhanced mitochondrial biogenesis and improved microvascular function.
 

Most research, however, finds little to no difference in endurance training adaptations when comparing post-exercise cold water immersion to no intervention or active recovery. My interpretation is that performing cold after endurance training is likely not as harmful as it is for strength training. Still, to be safe, you may want to do your cold exposure later in the day or on non-training days.

Exposure to cold temperatures induces a range of acute physiological responses, collectively referred to as the cold shock response.

Final Recommendations

If you’re focused on building muscle size, strength, or both, avoid cold water immersion in the immediate (1–4 hours) period after exercise. Instead, use cold exposure 6–8 hours post-exercise or on non-training days. Cold showers, on the other hand, are likely fine before or after exercise if you need a quick pick-me-up.
 

Could a short bout of cold exposure before exercise boost your alertness and energy? It might not have the same negative effects as post-exercise immersion, but due to the lack of data, I can’t say for sure.

I want to be clear: I don’t want anyone to stop using cold exposure because of this email. I still believe it's a powerful tool for enhancing mental and cognitive health if you enjoy it. But it’s important to be aware of the potential interference between cold exposure and the signals that govern muscle growth.
 

For those who don’t enjoy cold exposure, maybe this is just the excuse you needed to continue avoiding it.

If you want to learn more about the effects of cold exposure, you can watch two of my Question & Answer episodes, #11 and #39.

Relevant cold exposure timestamps:

• 23:42 - Where does cold exposure fit in on my list of tools & supplements for lowering inflammation?
• 24:30 - How exactly cold exposure lowers inflammation
• 25:00 - Cold exposure parameters necessary for increasing norepinephrine two-fold
• 25:22 - Why people become adapted to cold exposure, making it easier to tolerate
• 26:09 - How norepinephrine inhibits TNF alpha and decreases several harmful chemicals secreted by immune cells, helping to lower inflammation
• 26:39 - Why cold exposure and cryotherapy might aid people with arthritis
• 27:54 - Does the browning of fat reverse after stopping cold exposure?
• 1:12:54 - Could a cooling suit be a cost-effective substitute for a cold plunge?
• 1:14:29 - Are there any longevity correlations in populations who practice cold-water swimming?

Relevant cold exposure (and heat exposure!) timestamps:

• 1:02:35 - How heat shock proteins generated during heat stress boost the immune system
• 1:04:40 - Does the sauna reduce risk of pneumonia?
• 1:04:55 - Does frequent sauna bathing reduce the duration of the common cold?
• 1:05:10 - My sauna & cold shower protocol
• 1:05:57 - Does cold exposure boost the immune system?
• 1:06:40 - Does winter swimming increase white blood cell count?
• 1:06:50 - The cold exposure parameters shown to increase lymphocyte numbers and reduce the risk of colds in healthy males
• 1:07:12 - Does winter swimming reduce respiratory tract infection risk?
• 1:08:30 - Do I practice hot/cold contrast therapy?