It's 26.2 miles requires epic amounts of energy, stamina and determination. Raja Aslam however will running on empty when he does the Manchester Marathon tomorrow (Sunday).
He will join the starting line up while fasting during Ramadan. But it has not deterred him from taking part in a bid to raise funds for a charity helping survivors of the earthquake in February which cost 57,000 lives in Turkey and Syria.
Raja, a father-of-four, from Blackburn, who was brought up in Longsight, said: "This is the toughest challenge I have ever done.
When I run I will have been fasting for 24 days - eating and drinking nothing between sunrise and sunset. I just have to refuel at night with plenty of water and protein and carbs. READ MORE: Join the FREE Manchester Evening News WhatsApp community "I have been practising running while fasting - three weeks ago I did 20 miles in two hours 54 minutes.
Read more on manchestereveningnews.co.uk