Rio Haryanto is to take medical advice as he fasts for Ramadan.

During the Muslim holy month of Ramadan followers must not eat or drink between dawn and sunset.

This has led to concerns that the lack of fluid and food can lead to problems, and whilst there are exceptions, such as the very old and the very young, Muslim F1 drivers don't count.

Amidst concerns that fasting could impact his concentration today, Rio Haryanto will seek medical advice.

"Rio has been fasting this week," his manager Piers Hunnisett told Reuters, "but the team and his physio will decide what to do on Sunday. It's a long race and there is a worry about dehydration.

"Drivers lose a lot of body fluid during a race and we don't want him losing concentration when he is driving at 350kph or whatever it may be," he admitted. "It's more of a safety issue. He has been following his faith in Montreal this week but we will see what the advice of the team doctors is. On Monday he will be fasting again."