This week I had one of my more interesting check-ins on coach.me.

For the past 365 days, I have taken a cold shower.

Over the past year, this has taught me countless lessons about myself, fear, health, willpower and about habits in general.

Today I’m going to share the 7 best ones with you.

1. The fear doesn’t go away.

No matter how often you do it, that little voice in the back of your head, that says: “Come on, just set it to warm, just this once!” never fully goes away.

There will be times when you laugh at it and there will be times when you’ll listen closely.

Some days you’ll punch the knob to the coldest setting and be excited to step in.

Some days you’ll stare at the shower head for 30 seconds, shake your head, and set it to cold.

But it’s always there.

And that’s a good thing, because it means you get to beat fear again and again and again.

Every day after your cold shower you’ll step out, and you’ll be a champion once again.

2. Cold showers make you mentally tough.

Guess what beating fear on a daily basis does to you? It makes you mentally strong.

You’ll become much less whiny and not give in so easily.

You not caving in the morning and resisting the urge to take a semi-nap under warm water might make all the difference.

It could mean also not caving later at work, when your boss yells at you for something you didn’t do wrong — and you finally yell back…

…or not throwing a tantrum late at night when your honey forgot to bring the milk, yet again…

…or just not losing your cool in insane commuter traffic and therefore not crashing into some idiot who brakes for no reason.

Closely related to your newly found mental strength is this:

3. Your immune defense goes up. Way up.

Say what you will, cold showers make you toughen up. The physical difference is noticeable.

In the past year I’ve gotten sick much less than in any given year before. I had one, clearly stress-indicated fallout in March, which is also when my weight went down terribly:

You can tell where I got sick, right?

(weight in kg, measured over 1 year, daily until about January, then weekly)

You can feel the physical resilience this habit builds up.

I walk around in the rain, wear thinner clothes, don’t catch a cold from a slight breeze and can take a fair bit of spontaneous exertion, such as running to catch a bus, walking up 5 flights of stairs or getting up in the middle of the night to drive 450 miles to see my girlfriend on Valentine’s Day.

4. You can expect an increase in testosterone that’s…noticeable.

Quite a few studies have looked at the relation between temperature and fertility in men, some proving heat hurts testosterone production, others, like this one, linking colder temperature to a higher quality, volume and motility of sperm.

While there is a whole lot of rocket science going on around the topic, you don’t have to have a PhD to notice the effects.

When you get out of the shower in the morning, you’ll feel this after glow, sort of like an aura of confidence. It’s a great way to start your day because you’ll feel like you can tackle anything (and anyone).

You’ll know what I’m talking about and if not, let the ladies decide. (Or gentlemen, of course.)

5. You have to remain flexible if you want to make it work.

As with any habit, obsessing over how much you do it won’t help you get there.

If you start from zero and want to shower cold for 10 minutes each day, good freakin’ luck.

You’ll throw in the towel right at day 4 when you only manage to do 8:43 min and “everything is ruined”.

Start out small and don’t blow mistakes out of proportion.

As long as cold water hits your body from above at some point during the day, your good.

When I visited my girlfriend in Berlin, the old lady she lived with only had a bath tub. Did that mean crouching in a tiny porcelain structure, holding the shower head over my head and shooting cold water at my different body parts one after another? Yes. So?

Another example is when I got sick, and also in the winter, sometimes when the water hit my head I got a numb feeling, almost as if I was about to pass out — so I did 30 seconds of cold, showered and cleaned myself with a warmer setting, and then finished with another 30 seconds of cold.

Don’t be afraid to change things when they don’t work. Just make sure you get going and fix the details as you go.

6. You realize you’re stronger than you think.

I’m sure you’ve had this feeling before:

You’re trying something new, something you’ve never done before, or are about to start on a task you don’t feel very confident about.

You give it your best shot…and it works, at least sort of.

The moment I’m talking about is the one where you go: “Hey…I can do this! I’m much better at it than I thought I would be, I can handle this!”

This is called confidence and it’s one of the most important determinants of your success in life.

You’re ability to create a successful life, whatever that means to you, hinges on you being able to trust in yourself.

This little “Hey, I can do this!” moment you’ll have every morning when you take your cold shower will dramatically alter your faith in being able to handle life’s challenges.

This is the single biggest reason to take a cold shower every day.

7. Habit stacking works

I’ve talked about habit stacking before, and this showed me that it works, yet again.

Originally challenged by Tai Lopez on Day 12 of his 67 Steps, I decided to make cold showers a daily habit after the initial week was over on September 22nd, 2014.

I cued the habit right between getting up and having breakfast and it worked fabulously.

Repeat after me, if you want to do the same:

After I [wake up in the morning], I will [take a cold shower].

After I [took a cold shower], I will [eat breakfast].

Commit to doing this for a week, and soon you’ll be able to say:

So, what should you do now?

Very basic. Just 3 steps.

Walk to your bathroom. Take a cold shower. Tell me how long you lasted.

Who knows, you might learn something about yourself. And it probably won’t be on this list.