Fabio Capello's side arrived in Sao Paulo on Sunday after a long-haul flight from Moscow, and will again be boarding planes to Cuiaba, Rio de Janeiro and Curitiba for their three Group H matches.
Vasilkov, who travelled with Russia to South Korea and Japan for the 2002 finals, said such a drastic change in time zone was a significant factor in the national side's preparations.
"There is a whole new science about long-distance travel. If we move north to south – to Madagascar, for example – it's easy. Our bodies don't need to adapt," Vasilkov told Uefa’s official website.
"But if we go east or west and spend more than four hours in the airplane, then our bodies find it harder to adapt to new circumstances."
Capello has reportedly gone lightly on his charges in their first hours in Brazil, and Vasilkov said that was a sensible move from the former England boss.
"After long flights, players shouldn't be training really hard," he said.
"They need time to recover. Also, we have noted that it is harder to sleep if you fly east to west."
Vasilkov also said that players should not be consuming “fancy food” at a World Cup; but did recount treating some of the Russia squad 12 years ago.
"Fancy food is not welcome at these tournaments as the pressure on players' bodies is very high anyway," he said.
"We had to take individual needs into account, though.
"Back in 2002, I took some black caviar with me to spread it on bread to make some players happy. Believe me, it wasn't just for me!"
Russia's team chef Nino Graziano said he will provide only nutritional options for the players.
"We will say no to fatty food," Graziano said.
"Pasta, chicken, fish and rice with vegetables are welcome and of course meat, which is very good in Brazil.
"We will give the players plenty of fruit too. The team's mood and results depend a lot on the quality of their diet."