'It was of course very, very difficult, especially in the second half. We saw the temperature on the building, so maybe every 10K it was one degree higher and higher.'
The 30-year-old Indian clocked 4 hours 7 minutes and 55 seconds, which was 26:57 seconds behind the timing of gold medallist Matej Toth of Slovakia.
Britain's Mo Farah stormed to victory in the 5,000 metres on Saturday to secure an unprecedented third successive distance double at major global championships.
Check out the gold medallists on Friday, Day 14 of the Olympics in Rio de Janeiro.
P V Sindhu became the country's first-ever woman silver medal winner in the Olympic Games after coming second best against world champion Carolina Marin of Spain in a pulsating clash for the gold in the badminton singles on Day 14 of competition.