After almost 30 months of non-stop rugby, Thorn looked every day of his 38 years, and perhaps more, following the Highlanders' frenetic 49-44 Super Rugby win over the Wellington Hurricanes last week.
"My profile says I'm 38 but I'm feeling about 45 with some of the games we have had," he said after his team's third win of the season on Saturday.
Thorn's fatigue can be partially attributed to the fact he has not stopped playing since the end of the 2010 season.
In the intervening period, the lock has played in New Zealand, Japan and Ireland and helped the All Blacks to the World Cup and Leinster to the European club title.
The physical demands of crashing into hulking rugby players each week aside, the mental strain of the current season has weighed on the veteran of more than 100 Super Rugby games.
Thorn's recruitment, along with fellow World Cup winners Tony Woodcock and Ma'a Nonu, was seen as pivotal in providing the 'X-factor' the Highlanders needed to challenge for the Super Rugby title after two seasons of promise under coach Jamie Joseph.
Instead the team lost their first eight games of the season and were out of contention for the playoffs, which begin next week after the final round of games this weekend, by early May.
"It's not easy getting up every week," he said of the mental toll the season has taken.
"From mid-season we have been out of it and it takes ticker (heart), takes caring about each other and a bit of pride in who you're representing," he added after the Hurricanes game.
"I talked to the guys before the game and said that people often talk about playing for mates but we have been out of the finals since mid-season so this is exactly what we're doing.
"We're playing for each other. You're playing for your mate and you're playing for the people of Southland, Otago and those places."
The Mosgiel-born Thorn's intensely competitive streak, exhibited with a victorious roar after the Hurricanes' game, has kept him going this season and he looked forward to the team regrouping ahead of next year.
"It never changes for me. I have had years with the (Brisbane) Broncos where we lost four games all the way to the grand final and I still wanted to win those four," he added in reference to his storied rugby league career in Australia before he switched to New Zealand rugby.
"I just want to win every week."
The Highlanders travel to Melbourne for their last match of the season against the 12th-placed Rebels on Friday, and while his team will be saying goodbye to several players Thorn hopes to finalise an agreement this week for another year with them.
"I've had a crazy amount of footy, especially in the last two and a half years, and that was backed up by a lot of footy before that too," he told Fairfax Media.
"I'm keen to play some more footy. I feel pretty good, but I just need a break ... it's that simple."
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