DENVER – “Sucking the air out of a building” happens occasionally in the NBA playoffs, typically when the visiting team romps to an easier-than-expected victory or a rival player lights up scoreboard in front of someone else’s fans.

The idiom takes on a whole different meaning, though, at Denver’s Ball Arena, where the air always seems to have been sucked. And it’s not the out-of-towners causing or benefiting from it.

The city’s location 5,276 feet above sea level – rounding up for its “Mile High City” nickname – long has been credited/blamed for the effects it can have on unaware or unprepared visitors from lower elevations. Civilians can feel the effects of lower air pressure and decreased oxygen when they arrive, and the same often goes for visiting athletes.

Sure, they’re better conditioned than Joe or Jane Average, but they’re drawing more on the thin air in their competitive exertions. Many, if they’re being honest, have stories to tell about needing rather quickly to find their second winds. Or taking days, when they have them, to acclimate enough that their performances don’t suffer.

“Oh, it’s real,” veteran Denver Nuggets forward Jeff Green said this week. “I mean, it’s real for us too. We have to deal with it as well. It’s not something you get used to off the bat and ‘aw, it’s nothing.’ Sometimes if we don’t get a chance to practice, we feel it.”

Green, 36, has played for 11 NBA teams in 15 seasons, the past two with the Nuggets. So he has experienced some of the sluggishness, the shortness of breath, the lightheadedness, sleep issues, headaches and even nausea that can hit people new to the altitude.

“You feel it everywhere, through your whole body,” Green told NBA.com. “You just have to get over it. There’s nothing you can do about it.”

Well, you can always deny the symptoms and try to power through whatever limitations they impose. That’s what Miami Heat coach Erik Spoelstra sounded inclined to do when asked Wednesday, on the even of the 2023 Finals opener, what effect he expected the thin air to have on his team.

“We’re not getting into any of that stuff,” Spoelstra responded. “Our guys are in great shape. They’re ready to compete. If Denver wants to tip this thing off at the top of Everest, we’ll do that.

“This thing is going to be decided between the four lines. They’ve also got to come back to Miami. If you want to make it about that, we’ll turn off the air conditioning and they’ve got to play in 90-degree humidity, sap the [bleep] out of their legs.”

In Spoelstra’s world, O2 matters far less than Xs and Os. Especially with Game 2 set for Sunday (8 p.m. ET, ABC) and his team down 1-0 in the best-of-seven championship series.

The Heat, though, did turn in an uncharacteristically flat showing Thursday, less forceful than their usual brand of basketball, their shooting off. It’s impossible to say if thin air played a role or if something more tangible – like Miami needing a seventh game to finally eliminate Boston three days prior, then flying across two time zones to face a rested Finals foe – undercut them.

After Denver’s 104-93 victory, Heat center Bam Adebayo – his team’s most effective player with 26 points and 13 rebounds – shrugged off the mile-high angle.

“I don’t think that was part of the game anyway,” Adebayo said. “I didn’t even think about the altitude until you just said it.”

Or as veteran Kevin Love said when asked if he gets winded in Denver: “Winded? I get winded everywhere I’ve played.”

Still, it is something about which the Nuggets, along with their NHL (Avalanche), NFL (Broncos) and MLB (Rockies) brethren, want visiting teams to think. Physical effects can get amplified if the mental seeds for them are planted, and the sports franchises here are avid in their sowing.

At Ball Arena, there is signage where visiting teams enter and exit noting the city’s altitude. The numbers 5,280 are printed right on the court, near each free-throw line. The video board during introductions welcomes the road team with an ominous warning about the difficulty in catching one’s breath. And there are large, hazard-orange-and-black placards on display (“Attention: Altitude Warning/Low Oxygen”).

“I think the lungs tell you more than the signs,” ABC analyst Jeff Van Gundy said during the Game 1 telecast.

Miami is a superbly-conditioned, no-excuses type of team, so it is possible that if its players don’t mind, the thin air won’t matter. But even Nuggets players cop to suffering the effects, based on circumstances. Reserve Bruce Brown, for instance, acknowledged cramping up Thursday.

Also, the Nuggets’ franchise has an all-time record at home 1,238-641 in regular season games, compared to 662-1,250 on the road. In the NBA playoffs, Denver is 65-45 at home, 30-86 elsewhere. This season, its home marks were 34-7 in the regular season, 9-0 so far in the postseason.

Let’s not forget, either, that there is a whole school of athletic training based on high-altitude workouts. Olympic athletes routinely seek out facilities in Denver and Colorado Springs to boost their oxygen efficiency, and countless trainers and gyms simulate the effects with dedicated breathing equipment.

Those oxygen tanks that pop up on the sidelines at Mile High Stadium aren’t full of laughing gas.

“The altitude, actually, it is an advantage. It plays a difference,” Nuggets forward Aaron Gordon said before the opener. “I remember when I was in Orlando and coming to play against Denver, it was difficult just to get your first and second wind. But that [Heat] team is full of fighters. That team is excuse-less.”

The city of Miami – elevation 6.5 feet – is about as low as one. But the good news for the Heat is that most people do acclimate over the course of a few days. By the time Game 2 tips off, they will have been in town for six days. And with Games 3 and 4 spread across five days in south Florida, some of the Nuggets might be in similar shape if the series shifts back for Game 5.

“You’ve got to get used to the altitude every time we leave and come back,” Brown said.

If nothing else, the elevated nature of these games brings new meaning to the sports cliché of trying never to get too high or too low.

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Steve Aschburner has written about the NBA since 1980. You can e-mail him here, find his archive here and follow him on Twitter.

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