Entering the third summer in the shadows of COVID-19, gyms across Japan are coming face to face with a mask dilemma as they juggle ideas to prevent the spread of infection while worrying about severe summer heat.

While exercising when wearing face masks can cause a suffocating sensation and lower oxygen intake, some patrons remain reluctant to remove them in gyms' closed, indoor spaces.

A customer at a Copin sports club in Gifu works out while wearing a protective mask on July 13, 2022. (Kyodo)

That sentiment may be shared by more and more people in the coming weeks as the sharp rise in positive cases has signaled the arrival of a seventh wave of infections.

Yasuhiro Uno, a patron at a Copin sports gym in Gifu, works out while wearing a mask at the gym on June 28, 2022. (Kyodo)

"A part of me wants to take it off; it feels like it's suffocating me, but I can't help getting worried about COVID when I see people talking in the gym," 73-year-old Yasuhiro Uno said recently as he did weight training in the city of Gifu.

A 50-year-old man exercising at the same Copin sports club in Gifu, did not hide his discomfort about having to wear a mask while using a treadmill.

"I've slowed my pace and shortened my duration, but it's still hard to breathe. I believe we don't need to wear (masks) as long as we are exercising silently on our own," he said.

The operator of 53 gyms, mainly in central Japan, Copin requires visitors to wear masks -- swimming pools and shower rooms being the only exceptions. Masks pulled down under the nose are also a no-no.

"We can't do without masks if we want people to exercise with a sense of safety," its spokesperson Mai Chaya said.

A training facility run by the city of Niigata northwest of Tokyo, meanwhile, has eased its mask-usage instructions from "mandatory" to "whenever possible," stating that gym users can take them off during cardio workouts.

Kusanagi Sports Complex in Shizuoka Prefecture, west of Tokyo, which has installed numerous ventilation devices, also only "recommends" visitors remained masked.

One-on-one sessions with trainers in private rooms are gaining in popularity for those not wanting to be distracted by others. A personal trainer in his 40s from central Japan revealed that some of his customers sought out his personal gym after canceling gym memberships with major companies.

The choice of whether to wear a mask or not during private sessions is up to the customer, he said.

In the pandemic's early stages, some infection clusters were reported at gyms, and some local governments asked them to suspend operations alongside restaurants and live music venues.

Gifu University professor Nobuo Murakami. (Photo courtesy of Nobuo Murakami)(Kyodo)

Nobuo Murakami, a specially appointed professor at Gifu University, who is well-versed in infectious diseases, said masks should be worn during the summer, too.

"Masks are effective in preventing the infection of others, and keeping us from getting infected ourselves," he said. "There is no objective evidence that wearing masks causes heatstroke either, so we shouldn't demonize it just during the summer."

But he also suggested that gym users can strike a balance by taking their masks off when spaces are well ventilated and social distancing can be observed between gym patrons.

"I hope people can take notice of their surroundings and make wise decisions," Murakami said.

Related coverage:

Japan's daily COVID cases top 150,000, new record high

COVID-19 outbreaks in sumo stables disrupt Nagoya meet

Japan walks tightrope between no COVID restrictions, hospital strain