TORONTO -- Leo Namen breathes heavily, taking a breath between words as though just talking is making him winded. Ropes dictate where he’s allowed to go, and his oxygen saturation levels are just 89 per cent.

The Canadian climber and heart attack survivor is 5,364 metres above sea level, at Mount Everest’s base camp. Despite the restrictions put in place by the Nepalese government and the precautions taken at base camp, at least one climber has tested positive for COVID-19 and Namen said there might be more.

“There’s some controls that the government has put on to reduce the risk of this happening but still, there’s been some cases already of COVID-19 within base camp,” he told CTVNews.ca in a FaceTime interview on Wednesday.

Currently, there is at least one confirmed COVID-19 case in base camp but some climbers are concerned there are far more, and the Nepalese government isn’t particularly forthcoming with the data, tweeted Nepal journalist Rojita Adhikari.

“More than 30 people have already been evacuated with propellers to Kathmandu, with suspicion of pulmonary edema - later found to be positive for coronavirus,” Polish climber Pawel Michalski wrote on Facebook on April 28. 

Adhikari tweeted that she tested positive for COVID-19 shortly after her visit to base camp, and she’s pushing the government to release case data related to the mountain. 

Part of the problem is that people can develop what’s called Khumbu cough, or high altitude hack, a persistent cough as a result of the low humidity and cold temperatures.

“It’s very common to get this continuous cough that has nothing to do with COVID-19, but there’ve been cases also with regard to that,” said Namen.

The situation is made worse by the large number of people in base camp.

“In 2019 there were [381] permits issued, and this year up until [Wednesday], because they’re still open, there had been 408 permits,” said Namen. 

Even with 408 permits given out, there are far more people on the mountain and in base camp than that number. It could be upwards of 1,000, said Namen.

“When you think about the permits, you believe that’s only people who are going to climb Everest, but you have to multiply that sometimes by three because they need assistance, they need porters, they need sherpas,” said Namen.

There’s also the support at base camp, including medical support.

“It’s very disappointing for mountaineers and climbers here to see that instead of reducing the amount of climbers they’re increasing the amount of permits,” he said. “There are a lot of challenges aside from COVID-19 that we’re facing here.”

Despite the rumours of widespread COVID-19 infections, Namen said there are numerous precautions in place to prevent the spread of COVID-19.

“One of the new rules in base camp is there cannot be any interactions between expedition teams to avoid contacts,” he said.

He pulled on a thin rope dusted in fresh snow, snaking between tents -- a marker of where his expedition’s bubble begins and ends. The ropes run between all expeditions’ campsites in an effort to prevent climbers and guides from interacting.

“We all are in some sort of a bubble protocol,” he added.

And the COVID-19 protocols started before he left for Nepal. He was tested before leaving Canada, and again upon arrival in Nepal. Expedition members were to isolate separately for seven days, at which point they’d be tested again, he said.

With a negative test, expedition members could then board a small plane to Kathmandu. Expeditions are not to interact with each other, and all water, food and climbing supplies are to be handled by the team alone, with no additional help.

Like in much of Canada, masks at base camp are mandatory much of the time. Teams are not to share any gear, including kitchen items, tents and even water.

But, it’s not just COVID-19 fears that are giving Namen a difficult time. He’s now had food poisoning four times on the trip and speaking to him on his third day at base camp, he still wasn’t ready to climb the Khumbu ice fall.

“Honestly I'm not going to climb until I have the green light from the doctors,” said Namen.

Getting to the summit, at 8,849 metres, requires a lot of things to go right, and expending energy when he’s not in top health isn’t in his best interest.

Making sure he’s healthy before trying to climb is important because his body is currently working hard to acclimatize to the high altitude.

“Over time, there are adaptations, in terms of how oxygen is actually used in the body to make it more efficient to carry more oxygen on the blood, but you never really get back to how it would be in low altitude,” Craig Steinback, assistant professor in the department of kinesiology at the University of Alberta, told CTVNews.ca in an interview on Wednesday.

At extremely high altitudes people remain in a hypoxic state and once they start climbing, they’re using up even more oxygen, he added. With time, the body can make adjustments.

“That allows you to carry more oxygen per hemoglobin in the blood, you end up with more red blood cells that can carry the oxygen around, the tissues become more efficient at using oxygen getting more small blood vessels within tissues to be able to get more blood oxygen,” said Steinback.

But even giving the body time to adjust to high altitudes isn’t a sure sign of success on Mount Everest.

“Some of the fittest individuals go to altitude, they suffer, because their physiology doesn't come together to protect them from the low oxygen whether they're correcting for it or compensating for it,” said Steinback.

But even some of the effects of high altitude, like Khumbu cough, mimic symptoms of COVID-19. Those include pulmonary edema, which can have symptoms such as coughing, shortness of breath, and rapid or irregular heartbeat.

Pulmonary edema can come on quickly and descending to lower altitudes needs to be done immediately. Climbers are well prepared to look out for pulmonary edema, but Steinback worries about the consequences of someone who develops COVID-19 symptoms while climbing high on Mount Everest.

“I would suspect that you’d be in a scenario where someone may not even be able to come down because it becomes, frankly, it gets more and more difficult the higher and higher you go on that mountain,” he said.

That’s why climbers tackle the mountain in stages to get used to the ever-lower levels of oxygen and barometric pressure as they climb.

Namen and his expedition will work their way up to Camp 1, which is at 6,065 metres. There, they’ll stay one night before descending for base camp again. They’ll then make a push for Camp 2, at 6,400 metres, where they will again stay for a night before returning to base camp. After a couple of days rest they’ll go for Camp 3, at 7,300 metres, and stay for a few hours before returning to Camp 2 for the night and then back to base camp.

The final camp before the summit is Camp 4, at 8,000 metres. Above 8,000 metres is considered the Death Zone, where the body can’t acclimatize and begins to die, which is why climbers try to limit their time in this altitude.

For Namen, his first priority isn’t making it to the top of the world. It’s coming home. He’s climbing for his wife, daughter, sister and mother, he said.

He hopes to raise awareness about the lack of information about women’s cardiovascular health.

“Women are more likely to be misdiagnosed than men and there is insufficient information on how heart disease develops and appears in women,” he added.

In April, 2018, at the age of 48 he suffered a heart attack. Now three years later, as his 51st birthday approaches, he wants to show the world what a heart attack survivor can do.

If he makes it to the summit, he will be the first Canadian heart attack survivor to stand on top of the world.