Patrick Sang, a former Olympian and trainer of world record holder Eliud Kipchoge, said on Wednesday Kenyan runners must brace for the biggest challenge of running at night, which will demand their bodies to quickly adjust, which are used to morning marathons, reports Xinhua news agency.
"The biggest challenge for athletes running at night will be adjusting their bodies, which are used to morning marathons. They need to compete when their biological clock has not adjusted to the local time zone," Sang told the Olympic Channel.
The women's marathon will be held on Friday night in Doha where Kenya's Edna Kiplagat will be eyeing her third gold in fifth attempt.
Kiplagat, 41, won in Daegu (South Korea) in 2011, Moscow in 2013, was fifth in Beijing in 2015 and settled for silver in London two years ago. She will team up with Dubai marathon champion Ruth Chepngetich and Visiline Jepkesho.
Kiplagat says the main thing for her is to stay focused mentally.
World marathon record holder Paul Tergat (2:04.53) however, has downplayed the high humidity and soaring temperatures in Doha, saying it does not require any specific training or preparation.
The temperature in Doha as on Thursday morning at 6 a.m. was 32 degrees Celsius and humidity was 69 per cent, which was not much of change from the figures during the night.
The athletes have been subjected to numerous anti-doping tests to rule out cheats.
Last year, IAAF determined that Kenya together with Ethiopia, Belarus and Ukraine belong to a specific group of "risk countries", for which special rules apply.
One of the criteria is that athletes from these countries must have passed at least three "out-of-competition tests" and one doping test in-competition to be allowed to participate in the World Cup or Olympics.
( With inputs from IANS )