TORONTO -- Leo Namen breathes heavily, taking a breath between words as though just talking is making him winded. Ropes dictate where he鈥檚 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鈥檚 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.

鈥淭here鈥檚 some controls that the government has put on to reduce the risk of this happening but still, there鈥檚 been some cases already of COVID-19 within base camp,鈥 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鈥檛 particularly forthcoming with the data, tweeted Nepal journalist Rojita Adhikari.

鈥淢ore than 30 people have already been evacuated with propellers to Kathmandu, with suspicion of pulmonary edema - later found to be positive for coronavirus,鈥 Polish climber on April 28. 

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

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

鈥淚t鈥檚 very common to get this continuous cough that has nothing to do with COVID-19, but there鈥檝e been cases also with regard to that,鈥 said Namen.

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

鈥淚n 2019 there were [381] permits issued, and this year up until [Wednesday], because they鈥檙e still open, there had been,鈥 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.

鈥淲hen you think about the permits, you believe that鈥檚 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,鈥 said Namen.

There鈥檚 also the support at base camp, including medical support.

鈥淚t鈥檚 very disappointing for mountaineers and climbers here to see that instead of reducing the amount of climbers they鈥檙e increasing the amount of permits,鈥 he said. 鈥淭here are a lot of challenges aside from COVID-19 that we鈥檙e facing here.鈥

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

鈥淥ne of the new rules in base camp is there cannot be any interactions between expedition teams to avoid contacts,鈥 he said.

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

鈥淲e all are in some sort of a bubble protocol,鈥 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鈥檇 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鈥檚 not just COVID-19 fears that are giving Namen a difficult time. He鈥檚 now had food poisoning four times on the trip and speaking to him on his third day at base camp, he still wasn鈥檛 ready to climb the Khumbu ice fall.

鈥淗onestly I'm not going to climb until I have the green light from the doctors,鈥 said Namen.

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

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

鈥淥ver 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,鈥 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鈥檙e using up even more oxygen, he added. With time, the body can make adjustments.

鈥淭hat 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,鈥 said Steinback.

But even giving the body time to adjust to high altitudes isn鈥檛 a sure sign of success on Mount Everest.

鈥淪ome 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,鈥 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.

鈥淚 would suspect that you鈥檇 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,鈥 he said.

That鈥檚 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鈥檒l stay one night before descending for base camp again. They鈥檒l 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鈥檒l 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鈥檛 acclimatize and begins to die, which is why climbers try to limit their time in this altitude.

For Namen, his first priority isn鈥檛 making it to the top of the world. It鈥檚 coming home. He鈥檚 climbing for his wife, daughter, sister and mother, he said.

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

鈥淲omen are more likely to be misdiagnosed than men and there is insufficient information on how heart disease develops and appears in women,鈥 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.