WHITEFISH BAY, Wis. —

Last Friday was the 600th day Paul Koepnick went into Lake Michigan.

"It was never about going into the lake every single day. It was about making every single day count," he says.

This is more than fun for Koepnick. It's a type of therapy called cold water immersion, similar to ice baths and cold showers.

"This moment of absolute power and inspiration that you have inside of yourself -- to be able to get past your limitations in all aspects of your life."

To do this type of therapy, Koepnick says you need to follow the proper safety precautions and guidance.

"I don't advise people to go into the lake without someone who has been trained and who knows what they're doing

Click here to learn more about cold water immersion.

Watch the video above to learn more about this story.

MILWAUKEE — No matter the conditions, rain, wind, or extreme cold, Paul Koepnick has been starting his morning in the waters of Lake Michigan. He's formed this habit over more than 500 consecutive days.

If you happen to pass by Klode Beach in Whitefish Bay around sunrise, you've probably seen him.

So many people are curious that a small group now joins him. Koepnick believes it's not just a great way to jump-start your day.

He said developing the routine provided a pretty robust sense of accomplishment. He's now able to use the cold water as a motivating tool.

"You're training your brain just to jump and go in and do the hard thing," said Koepnick. "And you're going to see yourself push past whatever you thought you were capable of."

Koepnick has learned that cold water can provide him a ripple effect of energy and productivity that lasts the entire day, better than a jolt of java. And when the pandemic hit, it felt like less of an obstacle because he had a coping mechanism in place. "(The pandemic) didn't even phase me," laughed Koepnick. "The practice, when we go in, we're putting ourselves in deliberate fight or flight. And then we're teaching ourselves how to come down from that. How to manage that stress."

He admits he had to learn that kind of control. Koepnick's path to the lake's rocky shoreline began when he hit rock bottom.

"It started at the lowest point in my life where I was homeless, I was living in my car — and I was in a dark place," he said.

Koepnick has launched a 30-day "Cold Water Challenge." He's inviting others to try this out. And you don't have to get into the lake — it can be as simple as taking a cold shower.

He intends that the challenge creates conversation around mental health. Koepnick said the cold water was the catalyst that pulled him out of depression and anxiety and pushed him toward success in his personal life and career.

"Going into an uncomfortable situation every day and pushing yourself outside your comfort zone allows you to grow," he explained.

In 2022 Koepnick wants to begin teaching workshops about cold water immersion, including the science and research attached to using breathwork to control body temperature and muscle movement to re-warm and activate muscles.

You can learn more about that by visiting Koepnick's website and social media pages.

Andrea Albers at TMJ4 first reported this story.