The Long Haul: Cold Plunge

Welcome to The Long Haul! Every week, I’ll explore a longevity topic and then give a roundup of the big news in longevity.

This week, I’m telling you why you should consider cold plunge.

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Today's Topic: Cold Plunge

Cold plunge is a longevity phenomenon right now. Everyone in the space is running out to buy their own personal kiddie pool to ice bath in their backyard.

Early research shows that cold water immersion (CWI) has benefits, but science has yet to show irrefutable evidence. Most studies show positive effects but often with very small sample sizes.

So take this week's information with a grain of salt. Overall, CWI won’t harm you, takes little time & effort and has potentially massive benefits.

What is cold water immersion (CWI)

Cold plunge is defined as immersion in water below 60°F (16°C) for a short period (20 seconds - 10 minutes).

Cold water swimming, cold/ice baths, cryotherapy, and cold showers all count as CWI.
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Research shows cold showers may be slightly less impactful because it’s less “immersive” and the average shower doesn’t get as cold as the other modalities (average showers go as low as ~55°F / 13°C). [1]

How does it impact our longevity?

Lots of studies on CWI do not show causal evidence, meaning the benefits reported in the studies cannot be fully chalked up to cold plunge. Many of the health benefits could be correlated to the fact that people who cold plunge are generally health-conscious individuals and other things they do in their lives produce benefits. [2]

But there is some (small) scientific evidence that CWI helps with:

• Inflammation
• Stress regulation
• High cholesterol & heart disease prevention
• Immunity

To me, inflammation is the big one here. Centenarians are shown to have lower levels of inflammation than other seniors and low inflammation is a successful predictor of aging.
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The scientific basis of all the benefits is that regular CWI increases norepinephrine levels. Norepinephrine is a hormone and neurotransmitter involved in our fight-or-flight response.

An increase in norepinephrine:

• Enhances alertness
• Regulates mood
• Increases lipolysis (fat → energy) [2]
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Contrary to the myth that being in the cold makes you sick, CWI is shown to reduce the occurrence of upper respiratory infections and workplace sickness absence. [3]

How to do CWI

You could go buy a cold plunge tub, but I think it’s overkill given the small amount of causal evidence on CWI.

But a study of over 3000 participants found that spending the last 90 seconds of your shower in cold water reduces illness and increases perceived energy levels. [3]

So by turning your shower to its coldest setting for 90 seconds a day, you could reap some benefits. That seems worth it to me.

Biohacking bros seem to think cold plunge is the best – and I think once more scientific evidence forms, it'll be even easier to agree with them.

The Haul: What you can’t miss in longevity this week

Podcasts

• Dr. Benjamin Levine provides his weekly exercise regimen he believes is the best strategy for preserving heart health on the Found My Fitness podcast:
  • 1 long (1hr+) aerobic exercise session: dancing, long walk, fitness class
  • 1 high-intensity exercise session: HIIT
  • 2-3 moderate intensity base pace training sessions: use the talk test to get into Zone 2​
  • 2-3 resistance training sessions

Twitter

• ​We’ve all had something​

Thanks for reading.

– Robyn

[1] https://www.cedars-sinai.org/blog/cold-exposure-therapy.html

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9518606/

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025014/

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​DISCLAIMER: None of this is medical advice. This content is strictly educational.