When Portia O'Callaghan was diagnosed with multiple sclerosis on Super Bowl Sunday in 2004, she did not let that stop her from running.

"I have been a runner on and off my whole life, but mostly for fitness, not competitively," O'Callaghan says. "When I was diagnosed, I thought it was important to run while I still could, so I got more interested in it. I also thought it would keep me healthy, and I think it has. Since I've been diagnosed, I've run two marathons, five half-marathons, and countless shorter races. This year I'm running a 5K every month and hoping to PR (set a personal record) this fall."

Such a scenario might have seemed ridiculous when O'Callaghan, 39, began suffering from MS symptoms.

"My leg felt weak and I had never experienced anything like it before," she says. "I thought I had a virus or something so I went to the ER. The doctor told me I either had MS or meningitis. I asked, 'Which of those do I want to have?' The doctor said meningitis, but it turned out I had MS. He cried when he told me this, and I was really scared. When a doctor cries, you know it's bad."

It turns out that many people can have symptoms for years before they are diagnosed with MS. After her diagnosis, O'Callaghan was motivated to keep running because of her family. She says it is important to make healthy decisions because with each one she has the chance to live a normal life. She wants to stay healthy for her husband and their 9-year-old daughter.

"My husband is an ultrarunner and he inspires me every day," O'Callaghan says. "He gets up early, works eight hours at a bakery, then goes for crazy long runs in the afternoon. I have a wonderful, supportive running family in the Oiselle team, which is a Seattle-based women's running apparel company that has a team of 250 athletes -- mostly regular women like me, and some elite runners as well."

When O'Callaghan, who works as a user-experience designer, is not running, she enjoys her time with family and hiking. She tries to do core and strength exercises a few times a week. While O'Callaghan has been lucky that her MS symptoms haven't been more severe, she has experienced minor issues in balance, speech and fatigue.

"I became very motivated to eat healthier after having more fatigue in the past six months," she says. "I am mostly vegan and stay away from dairy, caffeine, sugar, and processed food. It sounded like a boring way to eat at first, but I feel great and already have less fatigue in the few months I've been eating this way. I also meditate every day for 10-30 minutes, which I think is great for calming the nervous system."

O' Callaghan writes about running with MS in a blog called Run Portia Run. She also recommends reading Overcoming Multiple Sclerosis: An Evidence-Based Guide to Recovery to anyone who is newly diagnosed with MS.

Related Story: Woman Says Diagnosis Of Multiple Sclerosis Was Blessing In Disguise

-- Follow Kaitlyn Kaminski on Twitter @kaitk96 and on her website Not Your Typical Jersey Girl.