MEASURING the debilitating effects of high altitude on sleep and appetite has taken an Ebbw Vale man to the highest mountain in the world.

William Harper, a former pupil at Monmouth School for Boys, worked alongside doctors and a hospital during an exhilarating three-week expedition in the Himalayas.

The University of Warwick student carried out research on climbers heading from Kathmandu to Mount Everest.

Everest presents dangers such as altitude sickness, weather, avalanches and icefall and Mr Harper battled his way to the South Base Camp in Nepal.

Having arrived in Kathmandu, Mr Harper and another student from Warwick formed a 10-person team, including four guides, for the 140-mile trek.

After flying to Lukla Airport, the group then travelled to Namche Bazar, trekking for up to seven hours a day over the next two weeks.

“As we climbed above 5,000 metres, the air became noticeably thinner,” said Mr Harper, a third year medical student.

"Turning over at night would render us breathless. The fatigue was crippling and even sleeping for 10 hours a night was not enough rest for our bodies."

He added it was an "incredible experience."