Victor Campenaerts (NTT Pro Cycling) has already hit the headlines for likening the effects of sleeping in his altitude tent to EPO, but after spending time sleeping at 4,700 metres, the Belgian has taken his oxygen deprivation to new levels ahead of the season restart in August.
Every day, Campenaerts simulates being at an altitude of 10,000 metres for one hour, he told Het Laatste Nieuws. For comparison's sake, the peak of Mount Everest stands at 8,848 metres, with altitudes above 8,000 metres referred to by mountaineers as the 'death zone'.
"Every afternoon I put on a mask for an hour and my oxygen supply is reduced," Campenaerts said. "The concept is called 'intermittent hypoxic training', scientific research has been done.
"The extremely low oxygen concentration gives your body an extreme incentive to produce extra red blood cells. I don't think many athletes do this. It's an experiment – I'm trying to be a pioneer and now I have time to try it out."
The effective oxygen percentage at 10,000 metres would be less than 6 per cent, half of what Campenaerts would experience at 4,700 metres, and a full 15 percentage points lower than it is at sea level.
Campenaerts said that he could only ride eight hours a week when he was sleeping at 4,700 metres, so tough were the conditions on his body. Meanwhile, pending time at double that altitude makes even the simplest of tasks near impossible.
"The oxygen supply is reduced," he said. "All I do is lie on the bed; I can't do more. It's pretty boring and then I start fiddling with my mobile phone, but I can't concentrate on it. Every word I type has a spelling error. It's very unpleasant and always a countdown until it's all over."
The use of altitude tents is permitted by WADA, though they have caused concern in the past, with WADA considering banning them back in 2006. The organisation's ethics committee deemed them "probably contrary to the spirit of sport", though no action was taken.
Last year, Campenaerts spent several months living at altitude in Namibia ahead of his successful World Hour Record bid, though the 1,800-metre altitude he experienced in the African country pales in comparison to his recent artificial efforts.
"Hopefully it will make me a little better again," Campenaerts said of his altitude tent and mask. "The intention is to occasionally sleep in my tent to lengthen the effect. The preliminary results are very good: I broke all my wattage records, but I hear that from different riders so it's not abnormal.
"We've never had such a long period in which we can train in such a structured way. That way, that had to pay off."
Campenaerts is targeting October's Giro d'Italia when the season restarts, given that the race will feature three time trials. He'll race the Czech Tour, Belgian National Championships and European Championships in August before taking on the Settimana Coppi e Bartali, World Championships and then the Giro.