She used to unwind by watching TV. Now, oncologist Joanna Lin runs marathons and recently finished an Ironman triathlon.
What do you do to keep fit?
My training each week comprises six to eight hours split into three or four sessions. I mix running, biking and swimming.
I trained for about six months for a recent Ironman triathlon.
During this time, I increased my training hours to around 10 to 12 hours per week, with a mixture of running, cycling, swimming, core training and speed work, as well as some open water swims in a wetsuit.
Has there ever been a time when you were not fit and fab?
I started exercising regularly only five years ago after seeing some close relatives and friends fall sick. I was 45 then.
I realised that I was approaching the age when illnesses begin to appear and I really wanted to stay healthy for my family.
I had never really exercised much before - except in school, and after that, the occasional tennis game and swim.
I spent most of my downtime watching TV and playing computer games. My husband even called me a couch potato.
What is your diet like?
I eat anything. But I generally stick to a low-fat diet and moderate my carbohydrate intake.
My breakfast is light, with a cup of coffee and some fruit.
Lunch is usually lean meat or fish, a moderate amount of rice or noodles and plenty of vegetables.
Dinner is similar, but with only a small amount of rice or noodles or potatoes as I don't need as much carbohydrates late at night.
I usually drink a glass of low-fat milk after dinner as it helps me sleep.
What are your indulgences?
I love chocolate and lemon meringue pies.
What is your work like and does it make it difficult for you to keep fit?
I work office hours and I fit my exercise sessions either before or after work.
I take my son to school at 6.30am and after that, I exercise for one to two hours, depending on when my first patient is scheduled.
After work, especially just before dinner, I sometimes go for a one-hour run or bike session.
What do you do to relax and how do you maintain a healthy work-life balance?
Since taking up more exercise a few years ago, I use it as a form of relaxation and hardly watch television any more.
My family likes going out to watch movies and we try to take a few short holidays a year.
Sometimes, we mix races with holidays - for example, my husband and I ran the Marathon Des Alpes Maritimes in Southern France a couple of years ago. It was a full marathon along the coast.
Just before last month's Ironman race in Melbourne, I went there a few days earlier to spend time with my son, who is studying there.
I think, in general, we tend to let ourselves go, health-wise, when we hit 40. This is rather dangerous as that is the time when many age- and weight-related illnesses start to emerge, such as high blood pressure, diabetes, heart disease and cancer.
Most of these diseases are preventable with a controlled diet and a fair amount of exercise.
In addition, as a doctor, I should set a good example for my patients.
I have noticed many differences since I started exercising regularly.
I have higher energy levels, better clarity of thought and am more calm and content.
Many people cite a lack of time, but those are excuses. Everyone has half an hour in their day that they could devote to exercise as opposed to watching TV or surfing the Internet.
What is most important is the will to change.
What are the three most important things in your life?
My family, my health and my work.
Would you go for plastic surgery and why?
No. I believe that it is possible to look youthful with a good diet and regular exercise.
Plastic surgery only helps with superficial looks. What is much more important is how you feel inside and if you are fit and healthy inside, you will look good outside.
Do you think you're sexy?
I think you should ask my husband that.
Dr Joanna Lin
Taking part in races is often a family affair for Dr Lin, an oncologist in private practice.
It started after a holiday in Hong Kong, when her brother-in-law, a keen participant in amateur races, encouraged her to try.
Her first, in September 2009, was to climb 73 floors in the Swissotel vertical marathon. She did it in 19 minutes.
Then her husband registered both of them for a 10km race in December 2009.
After that, there was no looking back.
She started doing triathlons in 2010. Since then, she has taken part in over 30 races, including 10km runs, half marathons, one full marathon, various aquathlons, duathlons and triathlons.
She did her first half Ironman race in March 2012 and another last August.
On March 23, she completed her first full Ironman race - a 3.8km swim, 180km bike ride and a full marathon - in 16hr 44min.
"It was my 50th birthday present to myself," she said.
Her family, including her orthopaedic surgeon husband Kevin Yip, two children, brother-in-law, sister-in-law and cousins, were there to support her.
She would definitely do another Ironman race again, said the mother of three children, aged 21, 19 and 11.
"It was an amazing experience for me and my family," she said.
This article was first published on May 22, 2014. Get a copy of Mind Your Body, The Straits Times or go to straitstimes.com for more stories.