Paul Caldwell, 63, tells Brain & Life how his background in physical education lifted him out of a depression after a diagnosis of Parkinson's disease.

I've always been known as an active teacher and coach. I did gymnastics in high school and college, and later taught high school biology and physical education and coached several teams over my career.

In my early fifties, I was training for the Chicago half marathon when I developed plantar fasciitis, which causes severe pain and inflammation of the fascial tissue that connects the heel to the toes. After treating me for several weeks, my podiatrist asked me to walk down the hallway and take a few steps back and forth. Then he asked if I acted out in my dreams. My wife, Jenny, who joined me during the appointment, laughed at that question, because I was known for acting out in my sleep.

The podiatrist recommended that I see a neurologist because he was 80 percent sure I had Parkinson's disease. (Many of his patients had the condition, so he was familiar with the signs and symptoms.) Jenny and I looked at each other in shock. As a biology teacher, I knew enough about the disease to know it was not good news. On April Fool's Day 2013, I saw a neurologist, who confirmed the diagnosis.

For more than a year, I sank into depression. Then I saw a segment on 60 Minutes that changed my life. Correspondent Lesley Stahl, whose husband has Parkinson's disease, reported on a therapy program, called Rock Steady Boxing, that was developed specifically for people with the disease.

The segment motivated me to research how exercise can help slow the progression of symptoms. Around that time, I learned that a friend's husband, Ted Deery, had the disease. We soon connected and joined a Rock Steady Boxing program.

After retiring in 2017, I started conducting fitness classes. I now lead an hour-long high-intensity interval training class over Zoom three times a week with a small group of friends, some of whom have Parkinson's. I also take two Rock Steady Boxing classes with Ted, lift weights, and walk with Jenny.

I never thought I'd be in such great shape at age 63. Because of my medication regimen and daily commitment to exercise, my symptoms are imperceptible, according to my neurologist. Not every day is perfect. Sometimes the fatigue is overwhelming, or my left foot goes numb with burning pain and I don't feel like teaching a class.

But the coach and teacher in me keep me going even on bad days. The diagnosis has only made me physically—and mentally—stronger. I am fully motivated to stay in the best shape and help others stay as active as possible.