WITH THE LIGHTS dimmed for the introduction of the starting lineups, Ball Arena directs everyone's attention to the big screen for an urgent message.

"ATTENTION, WARNING TO VISITORS."

Denver Nuggets public address announcer Kyle Speller proceeds to deliver a grim caution to the Los Angeles Lakers and their fans before the start of the Western Conference finals.

"All visitors to the Mile High City be warned," Speller says in an ominous voice. "High levels of exertion at this altitude may cause hypoxia with symptoms of fatigue, difficulty breathing, rapid heart rate, headaches and confusion."

The alert on the big screen begins to shake and blur as if altitude sickness has already set in. The next graphic shows an X-ray of an upper body with the chest area pulsating red. That is followed by a "Low Oxygen Levels" flash and the number "5280" with a heartbeat pulse darting across the screen.

"You have been warned," Speller says.

Just like the Lakers were advised, from the moment when the Miami Heat walk off the bus past a mural that reads "Welcome to the Mile High City, 5,280' above sea level" to the large "5280" next to each free throw line, the newly minted Eastern Conference champs will be reminded often they are no longer in South Beach, which boasts an elevation above sea level of just under Jimmy Butler's 6-foot-7 height.

Denver not only owns the most suffocating home-court advantage in the NBA, but no active franchise in history has had more success at home compared to on the road.

The altitude isn't a myth.

"Yeah, it's real," Lakers star LeBron James said before Game 1 of the West finals. "You get tired a lot faster."

When the Nuggets return to the court after a nine-day break for Game 1 (Thursday, 8:30 p.m. ET, ABC), the fabled Mile High altitude will make its NBA Finals debut. The Nuggets are 8-0 this postseason at Ball Arena, where they posted the second-best regular-season home record at 34-7 (Memphis was 35-6).

Trying to keep the 6-11, 284-pound Nikola Jokic out of the paint and off the glass while also chasing Jamal Murray through screens is that much more daunting when opponents feel like they need an oxygen mask while their legs and lungs tighten.

In case the Heat -- winless in Denver since the 2015-16 season -- don't feel the altitude physically, the Nuggets will do all they can to make them feel weaker mentally.

"That s--- real," Hall of Famer Kevin Garnett said recently on Showtime's "KG Certified. "You know what [the Nuggets] do before games just to f--- with your mental? 'Welcome to Denver. If you start feeling faint. It's because you are above [sea level] ...'

"You're like in the layup line, did you hear that s---? Yo, hold on. Whoa! Whoa! Did that [PA announcer] just say [5,280 feet]?

"You start having a panic attack."

FROM ANTHONY EDWARDS tossing a chair on his way off the floor after missing a 3 at the buzzer to force overtime for the Minnesota Timberwolves to Kevin Durant turning the ball over seven times in a Phoenix Suns loss, to James stunningly blowing a layup and later letting the ball slip out of his hands on a breakaway dunk, opponents have experienced some inexplicable out of character moments in Denver this postseason.

Nuggets forward Aaron Gordon knows what it is like to not feel like yourself in Denver, especially when visiting from Florida. Gordon needed to become a Colorado resident in order to feel acclimated to the Rockies.

"Most definitely, oh my God," Gordon said of whether he felt the altitude when he used to play at Denver during his six and a half seasons with the Orlando Magic. "Couldn't even feel my muscles. I feel like there wasn't even enough oxygen getting into my muscles when I played here. It was crazy. ...

"It takes maybe a week or two to get acclimated to it."

It's no wonder why the Nuggets own an all-time home winning percentage of .652. Away from Denver, the Nuggets are a paltry .350 all time. That .302 difference between home and road win percentage is the largest for any active franchise in NBA history, according to ESPN Stats & Information research.

The Denver altitude can get the best of everyone from savvy veterans to draft prospects. The Nuggets have had to cut some draft workouts short after seeing players turn pale and get sick.

"One of the main things that players coming into town feel is that they get desperate [for air]," said director of performance/head strength and conditioning coach Felipe Eichenberger, who has been with the Nuggets for 13 years. "You go for a sprint, you come back and you go for another sprint and all a sudden you just try to pull air. And then I feel like the players [feel], why can I not breathe?"

Detroit Hall of Fame point guard Isiah Thomas said he didn't know anything about altitude or what it meant to play in it since he grew up in Chicago and played his college ball at Indiana. Thomas played in the highest-scoring game in NBA history, a 186-184 triple-overtime Pistons victory at Denver in 1983. Thomas logged 52 exhausting minutes and scored 47 points against the run-and-gun Nuggets in thin air.

"If I did," Thomas told ESPN about whether he felt the elevation, "I didn't notice it."

Researchers, though, have noted that the Nuggets indeed have a unique advantage over opponents at home. According to a 2017 study published by four researchers that includes Michael Lopez, NFL senior director of football and analytics who was a Skidmore College associate professor of statistics, the Nuggets, Denver Broncos and Colorado Rockies all led in their leagues in home-field advantage when accounting for team strength. The Nuggets could expect to win 66.1% of their home games compared to the typical home advantage of 62%, according to the study.

"We play there once a year," Miami guard Tyler Herro said after the Heat's Game 7 win in Boston. "So we don't really have much experience [with] games in the altitude. We played in Mexico City actually this year which has a higher altitude [7,350 feet] than Denver.

"But you can feel it. It's an adjustment for sure."

The Heat didn't have much time to celebrate winning the East. Miami jumped on a plane and flew from Boston to Denver hours after Game 7, giving Erik Spoelstra's team more than 60 hours of thin-air acclimation before Game 1.

Potentially making matters worse for Miami is that one of the possible side effects of dealing with the altitude is a lack of sleep. According to a 2016 Athletes at High Altitude study by four doctors from the department of family medicine at the University of Colorado School of Medicine, "athletes often complain of insomnia, frequent awakening and restless sleep" at high altitude.

On the other side, the Nuggets will have slept comfortably in their own beds for nine nights before the Finals tipoff. The seven more days of rest they have than the Heat is tied for the second-largest rest advantage in Finals history, according to ESPN Stats & Information research.

"We've been here for a while now," Denver guard Kentavious Caldwell-Pope said, "working out, getting our breathing right, lungs, everything."

Whether it was legendary Denver coach Doug Moe's high-octane Nuggets offense trying to run Thomas and the Pistons off the floor or George Karl's teams that ranked in the top five in pace at home in all of his nine seasons at the helm, the Nuggets have long wanted to leave opposing transition defenses panting in Denver.

Nuggets coach Michael Malone stressed the importance of his team running and pushing tempo early prior to the start of the Western Conference finals. They currently lead all teams in home fast-break points per game in the postseason at 19.3.

"You see it all throughout the season when teams come in here," Malone said Tuesday about the Heat having little time to acclimate. "The altitude is real. [Miami] got in late [after Monday's Game 7], so they're going to try to acclimate as quickly as possible.

"... When we can establish that pace of play, that makes it really hard for visiting teams to kind of sustain and stay with that initially. Most teams will wind up getting their second wind and be able to work themselves into that. But yeah, the altitude is here, man. Might as well use it to our advantage."

Malone says he even hears from Nuggets legends to push tempo and take advantage of the elevation.

"When I hear from guys like Dan Issel, who will text me," Malone said. "And he said it in the Lakers series, 'Man, just keep running these Lakers off the floor.'"

AFTER THE NUGGETS finished 23-18 at home during the 2021-22 season with Murray out with a knee injury, general manager Calvin Booth had a staff member research what the competitive advantage is from playing at elevation and how the Nuggets can exploit it both physically and mentally.

Understanding that exercising at elevation can lead to symptoms of nausea, fatigue and cognitive impairment for those not acclimated, the Nuggets wanted to see when they could strategically push the pace and identify lineups that can play faster to maximize potentially the most influential home-court factor in the league.

"All the teams I've been on, essentially you're definitely going to feel it in the first couple minutes," Booth, who played 10 seasons in the NBA, told ESPN. "Typically, you get your second wind pretty quickly and you stop thinking about it. But now in a high-intensity environment like the playoffs, maybe late in the game it starts to affect you a little bit more."

Booth also wanted to examine how other pro and college teams that play at altitude try to get into the heads of opponents.

By halfway through this season, the Nuggets had devoted the majority of their allotted 30 seconds designated for introducing the opponent's starting lineup to their altitude warning. (It has forced Speller to go through the opponents' starting five as if he is competing in a speed reading contest.)

Speller will also slip an ominous-sounding "5,280 feet" during breaks in the game like he did during one coaching challenge in the fourth quarter of Game 1 of the conference finals.

"He just drops that in kind of subliminally when you can tell a guy is getting a little tired [or] made a bad pass," Craig Dzaman, Nuggets senior director of game presentation, told ESPN.

Dzaman credits Booth with the team enhancing the altitude theme during games. And with the Nuggets in reach of their first NBA championship, they're planning to find more ways to remind the Heat of what they're trying to scale in Denver.

Jokic, however, believes the Nuggets' play should get more credit for their home-court advantage.

"Maybe, maybe not," Jokic says of whether the elevation impacts the opposing team.

"We think it's us."

MURRAY IS GASPING for air as he stands at the free throw line with 19.4 seconds left in Game 2 against the Lakers.

Already feeling the lingering effects of an ear infection that left him mostly sidelined in the days leading up to the West finals, Murray is putting the finishing touches on a 23-point fourth quarter that wins Game 2. It is the first of two straight 37-point outings in the series.

"We are in Denver," Murray said. "Air is thin out here. But you just grit and grind ... Joker is exhausted, too. We all were tired, but we gutted it out.

"We know they're tired, as well. We play in Denver a lot, and they don't as much. So we know down the stretch, even if we're tired, they'll be just as tired or even more."

This moment is why Murray and the Nuggets train so hard during the offseason. Eichenberger takes players to Red Rocks, an open-air amphitheater built into a rock structure 10 miles west of Denver to run stairs, jump up the rows of seats and endure other lung-crushing exercises at 6,450 feet above sea level.

Eichenberger puts players through intermittent hypoxic training, during which they ride stationary bikes while wearing masks that alternate levels of oxygen.

During the season, Eichenberger makes sure his players acclimate back to the altitude following long road trips. Even the two-time MVP has to go through a short but "very intense" high-intensity session when Jokic returns from a sea level road trip, no matter how many heavy minutes and or how depleted his body feels.

"Just to activate his lungs," Eichenberger said. "We do that with him a lot. ...

"He's out of breath for a couple of repetitions and he's just like, 'Man, this sucks. But it makes me feel good.'"

Every step is to make sure the Nuggets outlast their opponents. According to ESPN Stats & Information research, the average speed of players on visiting teams in Denver decreases by each quarter from 4.20 mph in the first quarter to 3.89 mph in the fourth. And the percentage of time visiting players spend walking or standing still inside Ball Arena goes up from 69.1% in the first quarter to 73% in the fourth quarter.

"It can mess with your head, for sure," Eichenberger said. "You start thinking about a lot of things. It's just like, 'Man, am I crazy? Am I out of shape?' And you start overthinking."

This postseason, the Nuggets rank second in offensive efficiency and first in net efficiency, effective field goal percentage and true shooting percentage in the fourth quarter at home, according to ESPN Stats & Information.

"You can use your timeouts, you can do whatever," former Phoenix Suns coach Monty Williams said of trying to manage against the altitude before Game 2 during the second round against Denver. "I've been here and played before. You go through it early and as the game progresses, you get used to it a little.

"But I'm sure it does have an effect. That's not an excuse."

The Heat will be the last opponent tested in the Mile High City this postseason -- one heavy breath at a time.

"You can't stress out about it," Miami guard Gabe Vincent said after Game 7 of the East finals. "We're headed there right now so we'll have a little bit of an adjustment to do."

Not long after the exhausting series against the Celtics, Heat guard Kyle Lowry was already combating the altitude with Miami attitude.

"We'll be ready to go," Lowry said. "We're a team that's ready to go no matter where we are playing."

-- ESPN's Nick Friedell contributed to this story.