It came at the end of the first day of a self-imposed challenge to run the Milford Track and the Routeburn Track in two consecutive days during their summer break.
The 17-year-old John McGlashan College pupils said it usually took experienced trampers about three days to complete each track, across steep, rugged alpine country.
And they did it all to raise $3000 for the Otago Community Hospice and $7000 for the Child Cancer Foundation.
Andrew said it was 88km of pain and willpower.
''It was just ridiculous.
''I was so shattered afterwards. We went through two bottles of cramp spray each. It was quite gruelling.
''Before this, I had never ever run over 20km in my life.''
Ed said the last three hours of the first day were the worst.
''I was keen for some decent food and wondering why we were doing this.
''The fundraising thing, knowing people had donated money to see us do it, it pushed us on.''
On Friday, the duo were rewarded by the school for their achievement and were presented with special McGlashan Challenge sterling silver rings - the only jewellery permitted with the school's uniform.
Principal Mike Corkery described them as remarkable, challenging, courageous and generous.
''A Herculean challenge - 88km run in two days, who knows how many vertical metres, 8 hours sleep only, barely time to rest or eat and then, finally, the goal achieved and the satisfaction of being able to say: `We did it'.''
Ed said the pair's next challenges included running the Relay for Life and ''possibly'' running the Coast to Coast.
