[dardie]

Alternative hypothesis: The 79% who were able to complete the trial had already selected for 'grit', or folks who wouldn't skip a day's work for a minor ailment. To check, instead of just comparing the test group to the control group you would need to compare the test group to itself, before and during the cold shower period.

[watwut]

I can compare that on myself - I was very often sick (with common colds and such) and it got slowly better after I started cold showering regularly.

Cold swimming (which should include showering with cold water if you follow guidelines) is not exceptional here and people do report improvements in immunity. That is common reason for starting it - you are often sick and this is last desperate attempt to make it better after more pleasant methods did not worked.

[carlmr]

Maybe you just got mentally hardened. What you used to treat as a sick day now doesn't feel that bad. Not because you're less sick, but rather because a light cold doesn't seem so bad anymore.

[watwut]

I am 100% sure it is not the case.

It is also completely absurd to think that daily cold shower will mentally harden you so that you don't perceive sickness.

What I am confused about is the level of investment people have in idea that it can not possibly do something with body on physical level and absurdity people go to argue that.

[carlmr]

>I am 100% sure it is not the case.

What makes you so sure?

>It is also completely absurd to think that daily cold shower will mentally harden you so that you don't perceive sickness.

I didn't say not perceive sickness. I said that you wouldn't judge some levels of sickness to be as debilitating. I know enough people that sneeze once and don't work for a week. While others will only not go to work if they have a fever.

Both of those people feel worse with a blocked nose, but one of them doesn't judge it as debilitating (given they're not just scared of losing their jobs).

>What I am confused about is the level of investment people have in idea that it can not possibly do something with body on physical level and absurdity people go to argue that.

Why is it absurd to think of alternative explanations for the same phenomenon? I also never said it could not possibly be the case. I think you should take a look at it from different angles. It's unscientific to rule out something that's so well documented like mental effects (placebo).

[watwut]

> What makes you so sure?

Cause the difference between feeling better/being stronger and being able to overcome that is something I can evaluate. I know when throat hurts. You really can tell.

Also, the hardening effect is ridiculous, mostly because the actual hardening effect going on is that you stop perceiving cold water to be unpleasant. That is also not just psychological. You can stay longer and longer and longer without starting to tremble. For the record, trembling means you have overdone it and should go out asap.Hypotermia is real thing that happens to real people.

For that matter, with cold swimming, your resistance to cold will go up too and you will be able to stay much much longer then untrained people without trembling or being tired after.

All in all, if you follow guidelines and make water cold only gradually, you don't experience unpleasant feelings. With cold swimming (which tend to be natural progression once showers are boring), you experience high from endorphins it releases.

As in, it is the day in week you look forward, because it feels good.

> I know enough people that sneeze once and don't work for a week. While others will only not go to work if they have a fever.

Fewer is good immune system response.You can have no or low fewer and still feel pain or be weak. You described one person with good immune system and one with bad one.

> It's unscientific to rule out something that's so well documented like mental effects (placebo).

It is also unscientific to reject idea that something is not placebo.

[cies]

In other words: correlation is not causation.

I remember I've heard looooong time ago they used a similar method in Siberia to make primary school students stronger. Not sure if that's still practiced. But that cold exposure strengthens the body always stayed with me. (and now we have Wim Hof)

[Reedx]

That probably plays into it.

There's also a psychological boost and momentum to overcoming a challenge first thing in the morning, which makes subsequent challenges easier. Plus a cold shower and/or exercise gets the blood flowing.