SINGAPORE - Dr Marcus Cranston, 48, grew up in Montana in the United States, went to university in Oregon and has lived in different places in the US as well as Germany as a doctor in the US air force.
Four years ago, his active life was dealt a blow when he discovered he has Parkinson's disease.
A disease of the brain, it is characterised by muscular tremors, slowing of movement, partial facial paralysis and weakness.
But instead of feeling depressed, he decided to marry his sporting passion with his disease and do something for a worthy cause.
So in Mongolia on April 4, he embarked on a project to run four miles (about 6km) in 44 countries in four weeks and four days to raise awareness and funding for Parkinson's research.
The main reason he chose to run four miles in each country is the significance of the number four to him. But that distance also gave him a good balance between it being possible for him to complete, and also being a challenge.
He will end his run-the-world project in Las Vegas on May 6.
His run during the Singapore leg of his trip started and ended at The Parkinson Centre in Bishan on April 9.
He lives in Las Vegas with his wife, a Malaysian, and younger daughter, 14. Their older daughter, 19, is in college in Portland, Oregon.
He says it is the numerous non-motor symptoms, unseen by others, that often have the greatest impact on those with Parkinson's.
These include sleep and mood disorders, constipation, bladder problems, excessive saliva production, fatigue and loss of energy, depression, fear, anxiety and skin problems.
To follow Dr Cranston for the rest of his trip, go to: www.444ParkinsonsTraveler.org.
What do you do to keep fit?
I typically exercise five or six days a week. Over the past three years, I have mostly spent my exercise time training for triathlons.
I take part in three or four triathlons a year.
A typical day would see me either running for 40 minutes to an hour, swimming for 40 minutes to an hour or biking for one to two hours.
In addition, as a member of the United States Air Force, we are required to pass a fitness test twice a year.
How has having Parkinson's disease impacted your life?
In 2010, at the age of 44, I was diagnosed with Parkinson's disease, so that number is significant for me.
The disease threatened to take away my two favourite hobbies, sports and travel.
However, it has given me a cause towards which to apply my experience and interest in medicine and humanitarian relief.
It is my hope that my Run-the-World 4 Parkinson's Disease project can raise awareness of the needs of those affected by the condition worldwide.
Why is raising awareness important?
Parkinson's disease is a chronic, incurable disease.
It is estimated that more than five million people live with this condition worldwide and many do not have access to the medications that make the symptoms of the disorder manageable.
While we wait for better treatments and possibly a cure, the lives of those with Parkinson's can be greatly improved by increasing their own understanding of the disease, as well as the knowledge of the general public.
Too many people try to hide the fact that they have Parkinson's.
They feel shame and worry about how they will be judged in public.
If we can raise public awareness, so the public understands and accepts Parkinson's, hopefully those with the disease will be able to live a better life.
What is your secret to looking so fabulous?
I exercise for health and performance. The general well-being that I get from feeling healthy and the knowledge that a particular activity will make me clock faster timings in a run or triathlon motivate me to exercise.
Being fit happens to make you more attractive, too.
Has there ever been a time when you were not fit and fab?
In 2005, while playing football, I injured my knee and had surgery to remove part of the torn meniscus.
The few months after surgery when I couldn't be as active as usual were very frustrating mentally.
I also gained some weight and became less fit.
What is your diet like?
In general, I try to practise moderation.
There are no particular foods that I completely avoid or always eat, but I try not to eat anything in excess.
However, there are some things that I can't help but overdo, and most of these dishes are my wife's specialities such as enchiladas and chicken tikka masala.
What is your work like and does it make it difficult for you to keep fit?
My work is office-based medicine practice and programme administration. Therefore, I don't get much activity at work.
However, given that my job as a physician is about promoting health, it does motivate me to practise healthy habits myself.
What do you do to maintain a healthy work-life balance?
Fortunately, exercise helps me to relax.
I also enjoy watching sports of all kinds, both live and on television.
What are the three most important things in your life?
My family, ability to participate in the hobbies I enjoy and having a job that I enjoy doing.
Would you go for plastic surgery and why?
I don't think that would be for me.
Do you think you're sexy?
It is best to ask my wife, Lila, to answer this question.
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