As much as he's playing in the playoffs, it's possible to get tired just watching him.
The Chicago Blackhawks' top defenceman has skated over an hour more than the next closest player for a total of 537 minutes through the first three rounds. If Keith keeps playing 31:36 a game, he'll have the highest average ice time since the NHL and the Elias Sports Bureau began keeping track of in 1998.
Keith is on pace to play more than 600 minutes this post-season, a feat that has only been accomplished 31 previous times since 1998 and twice already by him. A third would put him ahead of elite company that includes Chris Pronger and Scott Niedermayer.
"He's kind of a freak as far as his metabolism and conditioning level," coach Joel Quenneville said during the Western Conference final. "Just certain guys genetically, aerobically, anaerobically, they can sustain it."
That's a common theme for minute-munching defencemen who have taken on a heavy burden on the way to the Cup final.
"I think that you get used to it," said Derian Hatcher, who averaged almost 28 minutes a game for the Dallas Stars in 2000. "I think when you're used to it and when you're conditioned to it, it's not a big deal at all. You kind of expect it."
Part of the expectation is on Keith, given the Blackhawks' lack of reliable depth on defence. Quenneville leans heavily on the 31-year-old Norris Trophy winner, Niklas Hjalmarsson (26:34 a game), Brent Seabrook (26:21) and Johnny Oduya (25:23).
After beating the Anaheim Ducks in Game 7 of the West final, Keith said he didn't think any player was tired this time of year. The excitement of facing the Tampa Bay Lightning in the Stanley Cup final is enough energy for the Blackhawks' Energizer Bunny.
If Keith continues playing over 31 minutes a game, he'll approach or surpass Nicklas Lidstrom's average ice time of 31:10 from the Detroit Red Wings' 2002 Cup run. If the series goes seven games and he keeps this up, he'll pass Los Angeles Kings defenceman Drew Doughty's total ice time of 747:33 from last year.
"Keith is a guy who knows how to manage his minutes well," said Lightning defenceman Matt Carle, who averaged 25 minutes a night for the 2010 Philadelphia Flyers. "You watch him play, he skates pretty effortlessly. But I've got to think it's been taking a toll on his body.
"He's not the biggest guy in the world. It's not like a Chris Pronger playing 30 minutes a night where he's cruising around."
Pronger averaged 30:57 for the Edmonton Oilers in 2006, 29:03 as Carle's partner in Philadelphia in 2010 and 30:11 during the Anaheim Ducks' 2007 run.
Keith is accustomed to this kind of workload, and Quenneville said the more he plays the more efficient he is. Hatcher, now co-owner of the Ontario Hockey League's Sarnia Sting, thinks some of that is psychological.
"What happens sometimes, too, is when you do get used to it, maybe other people are getting tired and you're not," Hatcher said in a phone interview last week. "Everyone thinks you're getting worn down but you're really not. ...
"The players that usually get that ice, they handle it just fine."
Keith is handling it better than fine with 18 points, tied for second on the Blackhawks and best among defencemen in the playoffs.
An injury to Michal Rozsival pushed Quenneville to rotate Kyle Cumiskey, Kimmo Timonen and David Rundblad in his the third pairing. The 40-year-old Timonen seemed to wear down more as he got hit, something that Hatcher considers the biggest issue with playing major minutes.
"The more you're hit the more tiring it is," Hatcher said. "Skating's easy for hockey players because that's what they do. But it's when you're stopped and started.
"Just like when you're running, someone stops you and you've got to start back up. That's where it becomes tough."
Carle knows that's the key to containing Keith in the Cup final.
"When you're competing and battling in your own end as a defenceman, that's where it gets tiring," he said Monday. "I'm sure we're going to try to make him work as much as possible and try to tire him out as much as we can."
Follow @SWhyno on Twitter