Mok Ying Ren, the 2013 SEA Games marathon champion, is confident about his chances of qualifying for this year's Games in Kuala Lumpur.
The 28-year-old, who will be targeting the qualifying mark of 2hr 37min 10sec at the Seoul International Marathon on March 19, said he is in the "tapering phase" of his training, and is taking the necessary precautions to stay fit.
"I'm just focusing on staying healthy and preventing myself from catching any bugs at work," he added.
"So I wear my mask at work and keep myself hydrated - it's just doing these small things to prevent myself from falling sick. That's my main focus now."
Mok, an orthopaedic surgical resident at National University Hospital, is also feeling good about his preparations, despite having to balance work and training.
He said: "(Doing) one run a day so far over the last six to eight months has shown that it's quite effective in terms of training benefits.
"The Seoul marathon will be the first marathon that I've trained for while working, so depending on how well I do, it'll give me a lot of confidence that this kind of training can still allow me to progress over the next few years."
Two spots in the marathon for the Aug 19-31 Games are up for grabs, with defending SEA Games champion Soh Rui Yong having already met the qualifying standard.
Compatriot Ashley Liew, who is also gunning for qualification, was just off the mark, clocking 2:38:30 at last weekend's Tokyo Marathon.
Liew, a chiropractor, revealed that he will not be running any other marathons until the qualifying window closes on May 31.
The 30-year-old will not be attempting to qualify for other events as well.
He said: "I've got to pick my fights. I know the marathon's always been my strong suit, and to switch to a 10km event... I wouldn't have the speed and the legs for that, so I'd rather stick to a marathon."
Liew, eighth in the 2015 race in Singapore, added that he was not disappointed about falling short of the SEA Games qualifying time.
"I've got to keep the bigger picture in mind as well - I love representing Singapore for the SEA Games, but at the same time I'm also still dreaming of Tokyo 2020," he said.
"And in order to get there I need to run faster times first, so if I can go to the SEA Games, that'll be great.
"If I don't, then I can focus on running a faster time somewhere else."
The duo were speaking on the sidelines of the launch of Runnerdotes: A Collection Of Anecdotes From Inspirational Runners, which is a book by Sundown Marathon founder Adrian Mok.
The book includes contributions from Soh, Liew and Ying Ren.
On the possibility of having two Singapore SEA Games marathon champions competing in this year's event, Ying Ren said: "I think it'll be exciting because prior to 2013, there was no male SEA Games marathon winner from Singapore, and two cycles later, there could be two (in the same event).
"Hopefully this year, we can show that it wasn't a fluke."
•Runnerdotes: A Collection Of Anecdotes From Inspirational Runners is retailing at $23 at all major bookstores. All Osim Sundown Marathon 2017 participants can also buy the book for $20 at sundownmarathon.com.