Finlay Wild is a top UK hill runner and mountaineer, having won many of the country's toughest races and set some impressive records on classic rounds and other hill challenges. This year he is competing in the World Skyrunning 'Classic' Series - a competition taking in some of the most prestigious mountain races in Europe and beyond. From the first race in the Himalayan foothills, through the summer in Europe to the series finale in Limone, Italy he is hoping to train smart, learn about these varied mountain places and cultures, and maybe even unlock some extra hidden running potential. He will be charting his progress on UKH.

The first race of the 2018 Skyrunner 'Classic' World Series was the Yading Skyrun – a 29km route ascending to a 4666m col in the beautiful Yading Nature Reserve of Sichuan Province, China. Sitting at five metres elevation in Scotland, I considered this. I've been mountaineering in the European Alps up to 4810m a couple of times. I've even trekked up Kilimanjaro as a student, dry retching at 5895m. But I'd never run or raced at altitude before. This would clearly be an extra element to the race and likely the main difficulty for most competitors.

I decided to give myself two weeks in situ before the race to recce the route, to explore the area, and of course to give some time for the myriad physiological processes of acclimatisation to take effect.

Arriving in China I was a bit apprehensive. I had no Mandarin skills and didn't expect many people to speak English. I had done my homework though and had plenty of information about the region I was travelling to, and how to get there. Landing at Daocheng Yading I buzzed with excitement as I looked out at the high steppe - boulder fields and rugged tundra for miles. At 4411m elevation this is the highest civilian airport in the world, and I certainly felt short of breath stepping out into the Eurasian sunlight. Outside the UFO-like small terminal there were two small buses waiting, and not much else. "Shangri La?" got me a nod towards one of them, and thirty minutes later we were off. My eyes were glued to the window - a dry, rocky landscape with small shrubs, steep crumbly cliffs and intermittent prayer flags interspersed with small, rural towns.

At Shangri La it took a while to find my hostel, but I was pleased to note the lack of in-your-face touts. Certainly I was the only Westerner around, and had been getting stares and even a few novelty selfie requests ever since my flight connection at Chengdu. Another thing that struck me was how industrious this rural town was: construction was going on everywhere.

Running on the flat was tough but possible, but on the uphills I was reduced to fast striding, hands on knees, lungs working overtime

My first run started from 2900m and took me along a dusty highway. I had to pick my moment to sprint past a large JCB which was working on the road. Following the lower part of the race route I headed up a steep-sided valley on winding singletrack. A Tibetan woman in traditional clothing smiled and pointed me up the valley as her silent baby looked on from within the safety of his multicoloured shawl atop her back. Winding up for around 14km I saw bright birds, squirrels, and perfectly clear water flowing down the stream. But no people - it felt remote and exploratory. Higher up it started to snow unexpectedly. I reversed my route with cold hands but a light heart; delighted to have got a run in after the long journey, although having felt pretty tired at the high point of around 3700m. Back in town, a group of workers had totally finished the skilled construction of a stone wall outside my hostel, using only their bare hands and a small wheelbarrow.

Taking the bus into Yading Nature Reserve the next day was quite a contrast. A huge extravagant tourist centre loomed bold, and hundreds of Chinese tourists queued to get on buses which drove the specially constructed road up the the park entrance. Getting off at the rather industrial road end I was soon clear of the crowds and free to take in the beautiful gold and technicolour Chonggu Temple, an ancient Buddhist lamasery at 4000m elevation sitting at the base of the holy Bodhisattva of Mercy, the unclimbed 6032m Xiannairi.

Walking up to the lung-busting 4666m high point of my race, I was gasping and out of breath. The path really wasn't that steep, but I was reduced to a steady walk. Putting in a few big steps to get up a short steepening - something which I usually do with no effort or thought - left my lungs straining and reminded me of how high I already was. The col was resplendent with thousands of metres of prayer flags - some lying thick against the rock, other strips flying in a high arc blown proud by the dry wind. Being still quite early spring, there was a fair amount of snow at the col, and I had to crouch to tunnel between flag and snow. Over the next two weeks the snow would all but melt, widening the prayer flag arch, although the actual race day was accompanied by some fresh snowfall. That evening I was reduced to walking very gingerly as I had stupidly forgotten to put suncream on my legs - bare skin in the reflective snow and high altitude sun had led to bad sunburn, which took a few days to settle down. The stupid tan lines took longer to fade, showing me up as the unaccustomed pale Scot.

Back in the valley there weren't a huge number of obvious trails to run. Thick trees and spiky bushes made questing off path difficult. The traversing trail I did find took me downstream to a small farming village. I practically had to climb over an electricity substation to continue on my way, which was just one of the many examples of the old ways clashing with the new in this rapidly developing country. Not long after, I met a group of farmers descending from their work in the terraced rice paddies on the steep rugged hillside. They were all smiles and handshakes, and incredibly friendly. Their way of life was in stark contrast to that of the camera-wielding urban Chinese tourists I had seen the day before, and of course my own. I couldn't help wondering whether the towering electricity pylons which traversed the hillside were held in awe or even a degree of worship by the locals, as huge symbols of modern progress.

Moving up to a base at 4000m I continued to explore, first making my way up the route of the vertical kilometer (uphill only) race. This trail soon left the busy confines of the orderly tourist walkways and wound its way up through fragrant larch forest, to emerge with breathtaking views of Xiaruoduo (5959m) across the valley. Higher still I passed a picturesque lochan, still partially frozen, and disturbed a pair of bar-headed geese. Reaching the 5000m col at which the race terminates I scrambled another 200m up loose unhelpful scree to a small subsummit. Looking around the countless peaks I was the only human visible - a very different situation from that of Scotland or the Alps on such a lovely day. Descending was of course much easier than my breathless ascent, and I started to get back into the flow of running fast in the mountains.

Snow was falling now, and gathering as a slippy thin layer covering the trail. The mist was down as I saw the leaders descend, not too far ahead. A final steepening to the col and I turned around to descend. Breaths were quick and deep - never have I been so aware of my respiration in a race, the need for oxygen my main limiting factor

The next few days were spent exploring the high terrain accessed directly from the small village of Yading where I slept. I took an ancient delight in running wild over many rough cols and chossy summits at or not far below 5000m. The wind and sun were both harsh, the rock barely touched by the passage of humans. Up at this altitude I needed frequent stops to catch my breath, but was rewarded by expansive views to the dry earthy high valleys, with hints of greenery seen in small scrub bushes and around watercourses. Higher the rock was dark, loose and weathered. Snow hung on in sheltered places, and was frequently blown by in a light flurry, quite bizarre in the bright sunlight.

Meeting up with some of the other racers was quite an occasion after over a week on my own. I'd purposefully left the 25km 'Kora' circuit to do with company. This is the clockwise pilgrimage walk around the holy peak Xiannairi that visitors often undertake over one or two days. Setting off with Holly, Hillary, Abby and Alli we jogged through the flat valley, passing beneath the mesmerising vertical strata of Xiaruoduo. Holly and myself pushed on and up through a gorge to the beautiful Milk Lake - a deep blue flatness amongst the dry contours. From a low point of 4300m I attempted a 'rep' up to the 4666m col of the race. Running on the flat was tough but possible, but on the uphills I was reduced to fast striding, hands on knees, lungs working overtime. Although I knew this was the effects of altitude, it was hard to avoid the creep of doubt as I had hoped to feel more race ready by this point, around a week before the race.

Later, I had an afternoon reading and mucking around outside a simple Tibetan shelter at 4600m, drinking in the head and shoulders of Xiannairi in the distance. To try and challenge my acclimatisation I did reps of thirty seconds uphill just behind the shack. Legs felt good, but the suffocating feeling of oxygen debt by the end of each repetition brought me back to ground quickly. The next day I headed up to over 5000m again, towards a loose but interesting peak. Enjoying the mental effort as well as the four limb scrambling contact, I packed it in shortly before the summit due to increasing difficulty and found a way back to the boulder field below. I suddenly felt exhausted - a likely combination of training, sun, wind and of course altitude. Time for a rest day and decent taper before the race.

After the inevitable apprehension of the pre-race buildup, we were in the Elite pen, just ten minutes before the start. The last few days had been a bit of a blur: an extravagant welcome dinner with performers, food, and endless toasts from local businessmen; a good rest and some easy runs, with a return to the more modest 2900m Shangri La; and a fairly sleepless night due to excited anticipation and a 5am alarm. The dusty rural town was transformed, more video cameras than I've ever seen at a race before, a huge excited crowd and around 400 racers bursting to start.

A countdown in Mandarin (starting at what?!) led to a sudden start, a fast pace through the deserted streets and onto the gently descending dirt road out of town. I hung back keeping it comfortable but heard later that the speed demons at the front were doing 5.20minute miles. After 4km we turned off at the tiny village of Kanggu, and started on the long undulating climb up the enclosed valley which led to the higher ground. At 3000m elevation this all felt good. I ran all but the occasional steep switchback, enjoying the winding path which kept my mind occupied while allowing me to get into my optimal sustainable 'race pace'. Runners were now spread out although periodically I would glimpse someone ahead through the undergrowth, and gradually reel him in over the kilometers.

Passing halfway, we emerged onto the road at about 3900m after 18km of fast running. A big local crowd was a boost but the proffered boiled water was difficult to gulp down - although better than giardia of course. Digging in, the road was thankfully short lived, before the route dived back into the thick forest. Approaching the Chonggu Temple I felt pretty strong. The trail steepened and I overtook another person on some switchbacks. Knowing the col was now only about 4km away I pushed on and up. The final section is quite undulating - I ran where I could, and power walked the rest. At one point a fast approaching Tibetan shepherd with mule required evasive action on my part. Snow was falling now, and gathering as a slippy thin layer covering the trail. The mist was down as I saw the leaders descend, not too far ahead. A final steepening to the col and I turned around to descend. Breaths were quick and deep - never have I been so aware of my respiration in a race, the need for oxygen my main limiting factor.

Trying to make up some time or places on the descent I ran on, and really enjoyed the technical but runnable narrow trail. It was amazing how quickly my breath seemed easier, descending and no longer working so hard at filling my lungs. Back in the forest the sun came out and, although I didn't manage to reel in any places I finished feeling strong and delighted, again a large crowd of spectators disorientating me. I was in fifth place, a little under seven minutes shy of the Andorran winner over a three hour course which was predominantly uphill and runnable. I felt I'd paced it well, and raced hard to get a solid result I was happy with. With the stunning mountains towering above and the golden temple shimmering off to the side, the post-exercise euphoria kicked in with more than usual power as I sat chatting to great people I had met during this unique trip. Relaxing at 4000m I didn't even feel slightly breathless, in sharp contrast to my first arrival here two weeks earlier. More important than the satisfaction of being one of the best acclimatised racers present, I also had some unforgettable memories of the many days spent exploring this beautiful empty corner of the world both with friends and alone over the past few weeks.

• Finlay is supported by Mountain Equipment and Norman Walsh Footwear