The South African opener, who laid a firm foundation for his team's mammoth 540, lost three-and-a-half kilograms while batting on the first day of the first cricket Test against India in Chennai.

It means, he lost one kilogram for every hour he stayed at the crease.

Mohammad Moosajee, the team doctor, was a worried man.

"Losing three and a half kgs in one day is a lot. The average loss should not be more then between one and two kgs.

"With the temperature at around 35 degrees Celsius and the humidity between 70 and 80 per cent, we have to take care of their hydration, heat tolerance, nutrition and recovery," he was quoted as saying in a South African daily.

Moosajee said McKnezie regained some of the lost weight, and got back to the same figure after the match.

"Neil got about two and a half kilograms back through the liquids and nutrients he took and the food he ate," he said.

Moosajee said lack of liquid causes problem for the players and they strive hard to maintain the body temperature of the players.

"The difference between cricketers and cyclists or racing drivers is that cricketers do not have liquids with them at all times. They are at the mercy of the umpires.