Adventure: Hard times on an 'easy' Bolivian mountain

Derek Cheng dreams of future summits - and no headaches - on a Bolivian mountain

A headache at 5400m feels like a million shards of glass stabbing just inside your temples. And being in a tiny, wooden shelter on the edge of a steep slope, 700m below the summit of Huayna Potosi, just adds to feelings of fragility.

I was gifting my high-altitude virginity to the mountain, in the Cordillera Real range, Bolivia. But the price was a head-splitter of epic proportions.

I tried to ignore it. Meditate. Hydrate. Medicate.

Pills for headaches, for altitude. Chewing coca leaves - the raw ingredient for cocaine, but a cash crop in Bolivia because locals like to suck them. The leaves are supposed to alleviate hunger, fatigue, altitude aches, everything.

Nothing worked. The insidious pulsing in my brain was all-powerful.

And I was freezing. I had insisted that my decade-old sleeping bag, which had been bleeding down for years, would suffice. But on this fateful night, the main zip gave way, turning my sleeping bag into a thin sack, split to the bottom.

Huayna Potosi is one of the world's easiest peaks over 6000m (it's 6088m), and a stone's throw from the comfort of La Paz, the capital city. Whereas several routes lead to the summit, the main one is little more than a trudge through the snow, starting from a lodge at the Zongo Pass at 4600m.

High-altitude had first floored me at 3600m, also in Bolivia - near the largest salt flats in the world. I had awoken one morning with nausea, dizziness, and that common ailment in developing countries - the runs.

But after a summer in Patagonia, I was so confident of withstanding the altitude that I didn't even bother upgrading my sleeping bag.

In La Paz, I chose the cheapest agency I could find, which kitted me and a Polish traveller with fleece jackets, Gortex shells, and snow and ice tools with sharp ends that imbue you with the sense of being a real explorer.

We drove to the lodge and were soon on the glacier with Juan, our guide, learning the basics: how to self-arrest if you slip, to walk in cramp-ons (like a duck, or a cowboy, to avoid tripping over yourself).

The following morning, we hiked up the lower craggy slopes, followed by a porter carrying food supplies. Not a cloud in the sky. At 5100m, we encroached the snowline and passed the lower camp, where many guided groups stay.

We continued up to our small wooden shelter and, with plans to summit at first light, we hit the sleeping bags at 6pm. By then, my head was already in a vice that was tightening at an excruciatingly slow pace.

After three hours, it had reached a merciless crescendo. I lay in my zipless sleeping bag, shivering. I walked outside, inside, and back outside again. I took pills, drank tea, took more pills. Hopeless.

After six hours of agony, I lay down, almost in tears. Somehow, I fell asleep. An hour later, when the alarms started sounding, I awoke. I have no idea how, but my head haze had mostly cleared.

We suited up, roped up, and started following the line of head-torches that marked the route. We moved steadily, taking deep breaths, resting every so often. The icy chill clung to my face, penetrated my bones.

A few hundred metres from the summit, we turned off the main route and up a steeper slope. Step like a duck/cowboy. Plant that ice axe.

The summit was encased in a wild cornice. As we reached it, the sun emerged from the horizon and bathed us in a wonderfully gentle glow.

Elation. The warmth from the swell of euphoria in my chest overwhelmed the chill on my skin, the fatigue in my legs, the squeeze on my lungs. To the west, the majestic peaks of the Cordillera Real punctured the sky.

In the daylight, the descent was easily negotiated. The altitude started playing with my head again as we drove out of the valley. But I had learned my lesson. Weary from the day's climb, I closed my eyes and went straight to sleep, dreaming of future summits and warmer sleeping bags.