Being thankful for a diagnosis of multiple sclerosis (MS) may seem ironic to most people.
But for Shannon Heo in 2010, it was like a gift of life.
Earlier that year, she had been mis-diagnosed with brain cancer, which she was told would take her life, probably in months.
To her, MS - generally a non-fatal neurological condition which has varying degrees of symptoms - was a much better option than life-threatening cancer.
Her first MS attack that year affected her balance and left her temporarily unable to feel her limbs or walk until she recovered and went into remission.
Having regained her mobility and despite a subsequent attack, the 37-year-old veterinarian will participate in next month's Osim Sundown Marathon with 30 other patients, volunteers and healthcare professionals to create awareness of the condition.
The recipient of the 2013 Singapore Health Inspirational Patient Award began competing in distance events for multiple charities in September that year and has already collected numerous medals.
But Heo, a mother of two children aged four and seven, confessed: "I hated running but I will never forget what my doctor told me - that as an MS patient, I have to be fitter than everyone else."
Determined to battle her condition, Heo took the doctor's advice and started training in September 2012 while she was in remission.
Just three months later, she ran her first 10km race. She credits the rapid improvement to a tip which one of her friends shared: "She said, 'On a treadmill, don't hit the stop button until you hit the goal that you have set'. And this tip has stayed with me."
However, she suffered her second MS attack in 2013, and the jovial Heo subsequently became withdrawn.
Overwhelmed by what she said was a feeling of guilt caused by the physical limitations imposed by her condition, she stopped talking to her family for three weeks.
But it all changed when she saw how her family and friends were rallying around her. "Everybody was supporting me and fighting for me. So why should I not fight for myself?" she said.
For Heo, running long races can also mean having her feet go numb halfway through an event, but she has never considered giving up and is even looking to running a 100km race before she reaches 40.
Her reason is inspirational, reflecting her courage and determination.
She will keep challenging herself, she said, because "I want to try 100km because I don't know when I'll lose the use of my legs".
This article was first published on June 5, 2015.
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