It is difficult to compete in the NHL.
Most seasons, players are going after each other in 82 regular-season games per year and they may play 20 or more games in the postseason.
The games are demanding physical contests and players often play three or four times per week.
Players may be bigger and stronger in the NFL, but those players are playing one game a week and have 16 games on their schedule per season.
The NBA is as demanding as the NHL from a cardiovascular perspective, but the physical nature of the play is not comparable.
Major League Baseball players play 162 games per season, but don't have the physical demands placed on their bodies that hockey players must endure.
Yet for all the rigors of the sport, hockey players often don't want to give up their sport. A player who keeps himself in top physical condition can play past his 40th birthday.
At the conclusion of last season, Detroit Red Wings defenseman Nicklas Lidstrom decided to retire. He was 42 at the time and he was still considered one of the best defensemen in the league when he chose to end his remarkable career.
Chris Chelios, a former teammate of Lidstrom's, played until he was 48 and retired reluctantly after the 2009-10 season.
Chelios was a physical defenseman who would light up his opponents with thunderous checks. Lidstrom was not considered as physical a player, but over the course of his career, he delivered and received many hard hits.
According to Hockey-Reference.com, five players 40 or older are active in the NHL this season.
While players who complete long careers almost always pay homage to the love of their sport as a key reason for their ability to stay active, that's merely an emotional reaction.
Former player Gary Roberts played until he was 42. He was considered one of the most remarkably conditioned players of his era and he now helps players maintain top physical conditioning so they can thrive in their hockey careers.
Roberts had to devote himself to conditioning after suffering a neck injury at the age of 30. He learned as much as he could about exercise and diet and put those principles into practice.
Now he teaches them to other players, including superstar Steven Stamkos of the Tampa Bay Lightning.
“I realized, after what I went through as a player, making a comeback and playing those extra 13 years, that I was only able to do that through the great advice that I got from friends in the nutrition world, and the strength and fitness world," Roberts told Toronto Star sports columnist Dave Feschuk. "I wish I had that information when I was 18, 19, 20 years old."
Roberts advises his clients to eat organic food and drink pure water to help their conditioning and longevity.
“I’m a little over the top with this stuff, you realize,” he told the Toronto Star. “I’ve never done anything half-assed before. And I want these athletes to have the right information. Even if they apply the majority of what I tell them . . . they’re going to be way better off. The only reason I played in the NHL until I was 42 was because of what I did off the ice.”
Roberts' success in the hockey-conditioning field is impacting his sport. Hockey players are paying attention to conditioning more than ever before and that gives them a leg up with it comes to longevity.
The love of the game may be the motivation, but it's the effort to prepare that allows older players to continue their careers.