Bone-jarring hits from a fired-up Manu Samoa won't be the only potential health pitfalls facing the All Blacks in Apia on Wednesday.
Sweltering heat of 29°C and 74 per cent humidity await the men in black when they kick off their Rugby World Cup campaign and play a historic first test in Samoa.
The sticky conditions compare with the 16°C high yesterday in Auckland where the All Blacks are in camp.
The All Blacks revealed midweek they would use ice packs before and during the game in a bid to cool body temperatures and limit fluid loss.
NZ Football medical director Mark Fulcher - who has overseen the preparation of All Whites' clashes in the Pacific - said some All Blacks could lose up to 4.8kg in fluids alone.
"The worst [conditions] would be no cloud cover, on a hot day with no wind," Fulcher said.
"[Samoa] tends to have weather like that."
Humidity will stop the players cooling off and Fulcher added players would need to steadily rehydrate after the game.
"You're going to replace [fluids] over a period of five to six hours," he said.
The All Blacks will fly to Apia tomorrow.
Awaiting them are Samoan players who have been preparing for the biggest game of their lives.
But Manu Samoa's large European-based contingent is also feeling the heat.
"It definitely doesn't get any easier playing in the heat. It's tough," said centre Johnny Leota from his ice bath.
Also awaiting the All Blacks is a rock-hard Apia Park.
Leota said the hard pitch could play into Manu Samoa's hands.
"I guess on the day you'll see the kind of rugby we're trying to play. Obviously we want to play the Samoan way - physical - and see what happens from there."