Haze running tips for outdoor runners in Singapore

She has switched to easy runs rather than speedy bursts of interval training. “Now is definitely not a good time to do interval training outdoors,” she says.

Track PSI readings, shorten or cancel runs

Runners and event organisers are tracking the haze and referring to government advisories to cancel, postpone or modify runs.

SGRC, for example, shifted its Oct 17 morning run from VivoCity to Canberra, as hourly PM2.5 readings have been lower in the north. About 30 runners turned up for the 30-minute easy run.

On Oct 24, the club will move its run indoors and do eight or 10 loops of Marina Square mall instead, before shops open. The mall first opened its space to runners on Oct 17, when about 15 enthusiasts from the community running group X-Run Singapore logged mileage of up to 19km.

Those who registered for running events in the last quarter of 2026 are still training, but some remain uncertain about whether their races will proceed.

The POSB PAssion Run for Kids 2026, scheduled for Oct 25, was cancelled on Oct 20.

Also slated for Oct 25 is the Garmin Run Marathon Series – Singapore.

Organisers say they are monitoring PSI levels and advisories from the National Environment Agency.

They will let registered participants know by 11pm on Oct 24 whether the race is cancelled.

The Great Eastern Women’s Run 2026, originally scheduled for Nov 1, was cancelled on Oct 16. Organisers cited the uncertain haze outlook in an Instagram post that day.

Organisers of the BYD Singapore International Marathon presented by adidas, which is on from Dec 4 to 6, say that training runs continue, though some have been shortened or cancelled because of the haze.

Lion City Road Runners is a weekly training programme that helps runners build up their mileage ahead of the BYD marathon. On Oct 10, planned distances of 24km and 18km were reduced to 12km and 9km, respectively. The Oct 17 session was cancelled.

Leon Lai, chief executive of SG International Marathon, which is organising the BYD Singapore International Marathon, says: “While we recognise that runners are preparing for their races in December, their health and safety must take precedence over training mileage.”

Running with an N95 mask not foolproof

Jack Seow, 35, has worn a surgical or cloth mask for his outdoor runs since the Covid-19 pandemic. In September, he switched to a KF94 mask, which filters 94% of haze particles, similar to the N95.

“I make sure to wear it tight and properly,” says the senior operations executive in market research.

He is “not a fan of indoor treadmills” and keeps his runs shorter, easier and in green spaces to reduce exposure to the haze.

He sometimes has to remove the mask and readjust it during a run, but says he usually completes the workout without removing it.

Poh says that wearing an N95 mask to run outdoors is not necessarily foolproof.

A well-fitted N95 mask with a good seal can filter 95% of airborne particles, but may not be comfortable or safe during vigorous exercise like running, he says.

“An N95 mask adds resistance to airflow, which makes breathing more laboured,” he says. This causes extra strain for people with existing lung and heart conditions.

“My advice is not to rely on an N95 mask to justify running outdoors in the haze when the air quality is bad,” he adds.

Train indoors with care

When the haze made it dangerous to run outdoors in early October, Justina Zeng, 44, signed up for a six-month membership at a private fitness chain.

Zeng, who works in banking, is training for a marathon in Hanoi in November, and for the BYD Singapore International Marathon.

“Desperate times call for desperate measures,” she says with a laugh.

She prefers to run outdoors and is concerned that training in air-conditioning will make it harder for her to run outdoors during the actual races.

“I’m worried I won’t be acclimatised to the environment,” she says.

Poh advises moving exercise indoors during this period of haze, especially if the indoor area is well filtered and well ventilated.

Air-conditioner filters alone cannot filter out PM2.5 particles effectively, but the building serves as a barrier to haze particles. A ventilation system can also keep outdoor air pollution from entering the gym.

“It is best to have an air purifier. If not, closing the windows and turning on the air-con or fan is the next best alternative,” Poh adds.

He cautions that outdoor air may still accumulate indoors if there are poor window seals or poor ventilation.

People with chronic heart or lung conditions, and other vulnerable groups, should take care when exercising.

Try resistance bands, push-ups, static and dynamic stretches, and balance-training routines that can be easily done at home, Poh suggests.

With outdoor runs out of the question, Tan consulted her trainer and focused on strength training and rest.

This period of alternative exercise has given her muscles and ligaments time to recover and led to better sleep, she adds.

As the hourly PM2.5 readings fell to elevated or even normal levels in various parts of Singapore on Oct 18 and 19, many runners she knew headed out for a run.

Tan continued to train indoors. “The 24-hour PSI is still high. I prefer to protect my lungs at my age,” she says.