[@RenaissancePeriodization] Cold Immersion Is Even More Worthless Than We Thought? (New Study)

Link: https://youtu.be/uhwvH6pVDOw

Duration: 13 min

Short Summary

Dr. Mike discusses a comprehensive meta-analysis of 30 randomized controlled trials (527 participants, 2008–2025) finding that cold water immersion reduces muscle growth stimulus when used within an hour after training and does not meaningfully restore strength or vertical jump performance. He declares "the era for cold water immersion" for performance recovery over, noting that partial-body immersion works no better than whole-body immersion, soreness and creatine kinase reductions largely vanish after publication bias correction, and the study population was nearly all male.

Key Quotes

1. "Cold water immersion does not meaningfully restore strength or jump performance overall." (00:06:20)
2. "the era for cold water immersion of well yeah it's not good for muscle growth but it obviously I'm doing it for performance because it enhances recovery that era to me is over" (00:11:54)
3. "Cold water immersion does seem to help some people feel less sore after hard exercise." (00:09:41)
4. "So, it for sure makes some people feel less sore. It doesn't dependably reduce mechanical damage indicators from a molecular detection perspective." (00:06:21)

Detailed Summary

Meta-Analysis Findings on Cold Water Immersion

Dr. Mike walked through a comprehensive meta-analysis of 30 randomized controlled trials involving 527 participants, with data spanning from 2008 through 2025. The immersion protocols tested ranged from 5 to 20°C for durations of 6 to 25 minutes, applied within roughly one hour after training across a wide variety of exercise modalities—including HIIT, resistance training, endurance running, rugby, basketball, jiu-jitsu, 10km downhill running, and half marathon protocols.

Muscle Growth and Performance

• Cold water immersion reduces the amount of muscle growth stimulus compared to not using it; Dr. Mike declared that "the era for cold water immersion" for performance recovery is over based on these findings.
• Cold immersion does not meaningfully restore strength or countermovement jump (vertical jump) performance overall according to the review.
• When publication bias statistical correction was applied, the reductions in muscle damage indicators (creatine kinase) mostly disappeared, suggesting many of the observed benefits may be artifacts of selective publishing.

Soreness and Recovery Markers

• Cold water immersion did reduce subjective soreness reports, and one subanalysis found lower creatine kinase, but publication bias correction mostly eliminated these findings.
• Partial or lower body immersion worked about as well as whole body immersion across outcomes, meaning neither approach was particularly effective for performance recovery.

Practical Recommendations

• Those seeking hypertrophy (muscle growth) should avoid cold water immersion after training.
• Peaking athletes like soccer players in multi-game tournaments may still benefit to prevent stiffness and soreness accumulation between events.
• The speaker could not extend conclusions to local icing or cryochamber, as these were not specifically studied.

Study Limitations

• The participant pool was almost exclusively male, limiting conclusions for female athletes.

Key Numbers from the Meta-Analysis

• 30 randomized controlled trials reviewed
• 527 total participants
• Literature date range: 2008–2025
• Immersion temperatures: 5–20°C
• Immersion durations: 6–25 minutes per session

Full Transcript

Show transcript

Let's say you want to reduce post
exercise inflammation. You're not
concerned with hypertrophy gains of
muscle size gains or strength gains.
Well, then get in the cold after your
your workout. Do that for one to some
people can do 10 minutes. Reduce
inflammation. The era for cold water
immersion of well, yeah, it's not good
for muscle growth, but it obviously I'm
doing it for performance because it
enhances recovery. That era to me is
over.
Hey folks, Dr. Mike here for RP Strength
and is it time to chill out on cold
immersion? Whoa, cool intro, Mike. What?
Let's talk about it.
What is cold immersion? Other than
having to hang out with an aunt that,
you know, has no sense of humor. It's
pretty cold.
You do sports.
Somebody tells you that if you get into
very cold water and sit there for a
while, especially after your workout,
especially immersing muscles that you
just trained,
especially with the goal of improving
recovery, that some good recovery things
will happen to you. And it's about as
simple as that.
Cold immersion says you immerse yourself
in cold, recovery will occur.
Now, you would think that this is kind
of some weird esoteric practice that
almost nobody does. It seems kind of
strange if you just look at it on paper,
but it is incredibly popular.
Health clubs are getting cold immersion
tanks and cryo chambers and stuff.
Professional teams of all sports all
around the world can't wait to do their
cold immersion.
People are taking cold showers at home
and about a million health hacker
podcasters are talking about how cold
immersing everything is supposed to give
you all kinds of amazing benefits. Now
what is it supposed to do in its best
realistic cases?
Cold immersion like all cold application
is supposed to reduce the inflammatory
cascade that you get after training to
enhance recovery.
and thus allow you to perform at the
same level that you were before the
exercise or close and maybe even improve
your mobility. So, it can prevent that
tight sore feeling that makes you
shittier at sports.
It can potentially make it feel that
you're not as sore, feel like you're not
as sore, which can enhance performance
potentially if soreness and the
psychology of pain is keeping you from
performing your best.
And it is supposed to be especially
useful in peaking and repaking athletes.
If you are a soccer player and you have
a one-day tournament where you play
three games or a two-day tournament
where you play four games, you don't
want the stiffness and soreness caused
by each game to successively accumulate
in future games. So by the time you get
to your most important game of the
tournament, you're the most jammed up
and super tight. So ideally in this
case, cold immersion after every single
game would keep you looser and more
performant such that you get to the last
game and you are on your jam feeling not
nearly as bad as you would have without
actually getting into the cold.
These are all potential upsides. The
known very wellressearched downside that
is pretty much definitive at this point
from multiple other reviews of
literature is that cold water immersion
within about an hour after you train for
muscle growth reduces the amount of
muscle growth you will be getting over
the next several days as your muscles
grow and heal. That's a given. We
already know cold immersion reduces
muscle growth stimulus
which sucks. But if you are a
powerlifter or a weightlifter, you're
training mostly the neurological part of
that whole system and the muscles are
about as big as you want them in the
near term. And if you have to peak or
train with super heavy sessions back to
back to back. If you are doing jiu-jitsu
or rock climbing or anything else, maybe
cold immersion can give you a boost in
performance where like you don't really
care about muscle growth for that
workout. Like people don't rock climb to
grow their muscles. Maybe if you can
cold immerse after rock climbing and go
rock climb again, you'll have a better
second session. So, it's not all about
muscle growth. We just know that's a
distinct downside already.
And so, there's a downside we know for
sure, and that's muscle growth gets
reduced. Not eliminated, but reduced.
But, cue my favorite meme in the world,
Anakin Padme meme. But we know that
there is an upside to cold immersion.
Right. Right. Scott, real quick, peak
Padme and Natalie Portman. Could she get
it out of town?
>> Oh, come on.
>> All right. Just checking to see if
you're awake.
>> Come on.
>> In any case,
>> who's going to say no to that? Come on.
>> I mean, it would be a very strange no.
>> If you say no, I got news for you.
>> Yeah, we got some news for you. Um, you
Scott, do you remember the uh Phantom
Menace, the the Star Wars episode one?
>> Sure.
>> Okay. Do you remember how she had all of
her like staff? It was a bunch of other
ladies dressed in uh slightly more uh
concealing attire and then she had a
like um a girl that looked like her that
was like the fake Queen Amadala.
>> Everybody every one of those could get
it 100%.
>> I don't give a shit. Like you know
that's not really Queen Amadala. I'm
like then do you hear me ask really
loud? Do you feel me? You know what I'm
saying? Just cuz you're an adviser girl
doesn't Anyway.
So, let's look at the actual data. We
have an amazing new document. A new
metaanalysis
shows up out of nowhere, bro. Just at
the club throwing bows at everybody. It
is a massive multi-study review. They
ended up with 30 randomized control
styles in the good god. 30 randomized
control studies, randomized control
studies, which means one group goes and
does cold immersion and one group does
placebo and
they tell both of them this will
probably help you and then they don't
get to pick their own groups and they
measure performance after the entire
meta analysis is 527 total participants.
Man, that that's a lot. That's a big
sample size. That's enough to start
telling some things apart with some
decent confidence.
Decent confidence. Most of them were
males. So we'll talk about that in
limitations a little bit, but this was
data that was published from the year
2008 all the way through 2025. That's a
lot of data. It is a lot of high quality
data.
And the cold water immersion protocols
in this data set were very varied. So we
can't say, oh, but they just tested one
type. They had temperatures of 5 to 20°
C, which is pretty goddamn cold to still
pretty cold.
Immersion protocols of anywhere between
six and 25 minutes. Scott, are you
interested in 25 minutes at 40 degrees
Fahrenheit?
>> Absolutely not. I'm not interested in 25
seconds.
>> Yeah, 100%. 25 anything really. And the
immersion depths
ranged from just partially like putting
in one limb to putting in your lower
body to like the entire thing up to the
neck because cold water immersion can be
systemic or it could be like just
immerse the area of your body that you
want to cool off in the immersion tank.
And now here's the really fascinating
part to me of this study. The exercises
they tested people in, the modalities,
the kinds of working out and fitness
that they tested people in
performance-wise
to see if they could get the degrading
performance out of them and then fix it
in the cold water immersion were many,
many different kinds. high-intensity
interval training, conventional
resistance training,
endurance running, they had rugby,
basketball, even jiu-jitsu was in there
and a few endurance protocols like 10
kmter downhill running and even half
marathon. So basically what we're asking
here, what the meta analysis is looking
at is if you do cold water immersion
within about an hour of these,
do your performance metrics come back
recovered more recovered than if you did
a placebo or just sat around doing
nothing? And the performance outcomes
mostly measured in this was strength
or jump height.
It's really simple. You do like an hour
of jiu-jitsu or whatever. Then you do
like 15 minutes of cold plunge. Then you
get out of the cold plunge and they go,
"Okay, we knew before you did jiu-jitsu
what your strength and your
countermovement jump was like, your your
vertical jump. Now we measure them again
and we measure them in the people that
did the cold water immersion and we
measure them in the people that did not.
And what ostensibly we would be looking
for based on the claims of cold water
immersion is that the cold water
immersion people would still be fatigued
from their earlier jiu-jitsu, but not as
much. And that would be reflected in the
fact that they are stronger and can jump
higher than compared to if they didn't
do the cold water immersion, which we
know from the control group.
Now, here's the hammer.
This meta analysis drew the following
conclusion.
Cold water immersion does seem to help
some people feel less sore after hard
exercise. They reported feeling less
sore.
And in one subanalysis, creatine kynise,
which is a measure of muscle damage, was
lower. But when they applied a
publication bias statistical correction
to this data set, that mostly went away.
So we could have made the claim that
cold water immersion causes less muscle
damage, but we're not even comfortable
making that. So, it for sure makes some
people feel less sore. It doesn't
dependably reduce
mechanical damage indicators from a
molecular detection perspective.
But here's what it for sure does not
meaningfully do according to this
review. Cold water immersion does not
meaningfully restore strength or jump
performance overall.
And here's a really trippy thing.
partial or lower body only immersion
work just about as well as whole body
immersion across outcomes, which is a
fun way to put it because just about as
well when you're not working is just
about as doesn't do anything.
Now, before we really crank on this the
poor neck of cold water immersion, let's
step back a second and be a little
scientific here.
This the law of averages.
Some people really feel better after
cold water immersion and maybe they get
performance enhancements.
On average, there was no performance
enhancement, but we can't say that's not
the case for all people. So, if you
really feel amazing after cold water
immersion, I'm not going to tell you
there's a 100% chance it's doing nothing
for you performance-wise.
And these studies didn't focus on local
icing and they didn't focus on the
cryochamber. But mechanistically, it's
all cold. But we can't be so specific to
say, "Okay, cryo doesn't work for sure
either." Now, this study group was
composed almost exclusively of males, of
very few females.
Sounds like my Hangouts, which means we
can't really conclude that for females,
cold water immersion is equally
ineffectual as it is for males. Let me
tell you guys something that I seriously
mean exactly as I'm saying it.
the era for cold water immersion of well
yeah it's not good for muscle growth but
it obviously I'm doing it for
performance because it enhances recovery
that era to me is over
based on this very expansive
comprehensive review of the literature
and it means that the next time you
think about doing cold water immersion
for any application including definitely
hypertrophy and even sport performance
performance, think again.
Because if it's growth you're after,
definitely don't do cold immersion after
you're training. Maybe do it hours later
or something if you're into torturing
yourself like that. It's a vibe for
sure. I get it.
But if it's performance recovery you're
after, well, cold immersion probably
doesn't do that seemingly.
So, are you cold plunging because it is
an evidence-based thing that is
increasing your performance, or are you
cold plunging because it's a vibe and
you still haven't gotten the memo that
it probably does not improve recovery
and thus does not affect performance and
doesn't help you become more of a spring
chicken at your next basketball game.
Because if that's the case and cold
water immersion actually doesn't work,
it looks like the science
of cold water immersion just got a bit
chilly.
I always wanted to do that reporter
thing. Anyway, I'm going to go take my
testicles and put them into cold water
only for psychological punishment, which
I deserve. And I will see you guys next
time.