A team of 50 took part in a relay using weighted stretchers that were carried in laps around the track, all in aid of the Hampshire Autistic Society.
The rigorous event saw them run 111 miles – the distance from Portsmouth to Cardiff – relaying with one hour on and two hours off for each team member.
The whole college, which trains people for a career in the armed forces, took part in the event at the Mountbatten Centre running track.
Students persevered even though they were cold and tired.
Daryl Dine, 18 said: 'I wanted to take part in the event as it was for such a good cause.
'I was exhausted when I was doing it and my legs were killing me but I tried to stay focused.
At the end of it I was so tired but relieved I'd done it.'
Charleigh Powell, 16, said: 'It was a great sense of achievement when it was over and amazing that the whole college took part, we are all like family.
'At about 3am I felt like i wanted to give up but everyone else was there to keep me motivated.
She added: 'I couldn't believe how much we raised.'
The college, in Twyford Avenue, North End, raised more than £1,200 for the charity from sponsorships and donations from family friends and well-wishers.
College manager Brian Richardson, said: 'The students had great fun putting themselves to the test in the name of charity.
'For many youngsters this was the first charity event they've taken part in and I know they were spurred on by the fact that the money is going to such a good cause.
He added: 'They all performed brilliantly.'