He used to get epileptic seizures at least once a week and was overweight because of his sedentary lifestyle.
That was until hospital porter Muhammad Jazlan Ahmad bought a bicycle in 2012 and started cycling leisurely, after his doctor warned that he was at risk of high blood pressure and other heart conditions.
His newfound love for cycling also led him to pick up swimming and running. Training five times a week, he lost 20kg in nine months in 2012, after weighing 80kg at his heaviest in 2011.
Not only is Jazlan in better shape now, his medicine dosage for epilepsy has also been reduced as a result of his weight loss.
The frequency of his seizures also decreased from once a week to once a month.
Said Jazlan: "Stress was one of the main triggers of my seizures and cycling really helped to relax my mind and destress."
As cycling is a form of aerobic exercise, it releases endorphins to "burn off the stress hormones", said Dr Wang Mingchang from the National University Hospital's Sports Centre.
"Endorphins make us feel good and counteracts the effects of stress," he added.
The 31-year-old Jazlan is currently training for the May 5-6 OCBC Cycle and is confident of completing the 23km route.
He said: "I hope I can make some friends and find more people to cycle with next time."
That is something he would not have imagined possible after being diagnosed with epilepsy at age 10.
During school days, Jazlan could not attend physical education lessons with his friends because of his epileptic seizures, which occurred at least once a week.
He was looking forward to national service after he graduated in electrical technology from the Institute of Technical Education in 2004, only to find out he was completely exempted.
He applied for jobs in the healthcare industry but was unsuccessful due to his medical condition. His multiple attempts to enrol in healthcare assistant courses were similarly met with rejection.
After doing odd jobs for several years, he became a hospital porter in 2011. But, due to his medical condition and weight, he was entrusted with only simple tasks like delivering documents.
"I saw myself getting from bad to worse, my weight was going up, I was frustrated that I couldn't do a lot things just because I have epilepsy," recalled Jazlan. "I felt like I was living in a very dark world and I didn't know what to do next."
Determined to lose weight, Jazlan took up cycling. But doing sports in his condition was not the easiest. He had to learn special breathing techniques to reduce the risk of seizures during exercise.
He once fell off his bike during an attack and dislocated his left shoulder. But an undeterred Jazlan refused to throw in the towel.
"I know I could have stopped cycling, but I really wanted to fight the seizures and lose weight," said Jazlan, who now clocks 30km per session at least twice a week.
Things are also better at work as he is able to handle physically demanding tasks.
He said: "From fetching documents to being able to assist patients in critical condition, knowing that people finally trust me to do important tasks makes me feel happier."
• Online registration for the OCBC Cycle is open. For more information, visit www.ocbccycle.com