I've had the climb of my life

Rising over the northern half of Lombok, the mighty Gunung Rinjani (3726m) is Indonesia's second highest volcano and has spiritual gravitas. Balinese Hindus and Sasak Muslims consider it sacred and make pilgrimages to its peak and lake to leave offerings to the gods.

But we were after a more earthly satisfaction. As part of our desire to climb anything we saw and the fact that we've summited higher mountains before, we thought it would be a lovely way to get the muscles in gear. Turns out 'lovely' isn't quite the word we were looking for by Day 3...

Sunday (Day 1)

0630 Wake up for freezing cold shower. Nice start.

0730 Head to Gunung Rinjani Trekking HQ.

0800 Meet up with our company for the next three days: our guide, Aldo, a local from Senaru who has climbed the mountain twice a week since he was twelve and gets his 'f' and 'p' mixed up ("Can I listen to your I-fod?"); our porter who carries 50kg of food, water, cooking equipment, tents & sleeping bags tied onto a bamboo stick up and whose name we could never pronounce so just called him Muscles; and fellow Englishman Matt who was to climb the mountain with us. A cracking young gent who put up with our pace and had an endless supply of sweets, Oreos and good chat. At 22, he also showed us how unsprightly we are after ten years of sitting behind a desk. Our merry band begins the trek.

0801 - 1130 James and Matt talk about camera geekery non-stop for the first 900m uphill. Nicola walks fast through the tropical forest to try to avoid the chat.

1130 Deceptively early lunch at 1,150 metres of fried noodle soup and pineapple. Muscles is a genius: from no wood or water to a boiling sugary cuppa in less than ten minutes.

1230-1600 James and Matt talk about management consultancy non-stop for the next 1,100m up. Nicola tries to walk fast to get away but realises she can't walk that quickly up the steep hill any more.

1600-1700 Emerge from the forest into the clouds. The mountain has real climatic significance. The peak attracts a steady swirl of clouds which shower the valley and feed the tapestry of rice paddies, tobacco fields, cashew and mango trees, banana and coconut palms. This is our last push to our campsite for the night and we're now scrambling up very steep rock and sand. Nobody talks this time.

1700 Arrive at one of the best camping spots in the world, overlooking the Danau Segara Anak lake and the mountain's newest volcano cone, but still overshadowed by the mountain summit. Take a look at the photo album to catch a glimpse of the tent clinging to the crater rim 1.4km above the starting point, 1km above the lake and 1.5km below the summit.

1800 Tuck in to some well-earned & freshly-cooked mountain food. Yep, fried rice and pineapple.

1900 After a beautiful sunset & fantastic stars, weary muscles find their way into bed to re-energise for Day 2. Unfortunately, it's freezing cold & a rock hard floor (perhaps unsurprising given that we are sleeping on a volcano...) so sleep never really comes.

Monday (Day 2)

0800 - A three hour descent from the crater rim to the volcanic lake. Worryingly the volcano in the middle of the mountain, Gunung Baru, last erupted in 1994 and was smoking so badly for 9 months last year that they stopped any walks in the area. It remains highly active. Ace. (Aunty Val-cano: you'd have loved to learn more about it as the newest cone actually only sprang up 200 years ago)

0932 - What we thought was going to be a fairly restful middle day turned out to be a rock scramble down some pretty gruelling faces. Suddenly we hear a girl scream, followed by the shout of "Grab something", followed by a second scream, and a shout of "Did you hear anything break?". A girl in the group ahead of us had slipped and thankfully her "grabbing something" meant she'd 'only' slid 15 metres down onto a cliff edge (rather than carrying on over the cliff edge and then 800 metres into the lake below).

0934 Our guide admits that someone in his group fell this time last year. A bit more probing and it turns out "fell" actually means a Russian photography emthusiast got too close to the edge taking snaps and fell to his death via a rock that split his head in two. You'll note there are no pictures of our descent into the lake after 0934.

1100 Arrive at lakeside (not the shopping centre) inside the immense cordera. We're now 1000 metres below the rim looking at a stunning 6km wide blue cobalt lake. As the volcano remains active, it pumps out hot water into nearby springs which was most welcome.

1230 Unfortunately there was only half an hour for spa action before lunch (fried noodles and pineapple) and another three hour slog up the opposite crater rim.

1600 Arrive at another amazing campsite, this time on a bare ridge from which we could see out to Bali, Sumbawa and, gulp, the start of our early morning climb to the summit. We dig in to more fried rice and pineapple, oh yum.

Tuesday (Day 3 'The Big One')

0200 Alarm clock beckons in the form of a wild dog, and tea and biscuits (from our guide, not the dog). As you can see from the photo in our album, we are not what one calls "up for it" just yet.

0300 Thermals and headtorches on, we begin the "3" hour climb to the summit. And we really do mean climb. After two hours of climbing up to and walking along the mountain ridge, we reach the part that even the locals who make their sacred treks there say is "difficult", partly because of its steepness, the darkness and altitude, but mainly because of the surface of lava granules. It can only be described as walking through fresh knee-deep snow powder, uphill, wearing ballet pumps. Three steps up and slide back two steps. In James' words: "this is the hardest hour of exercise I've ever done" - girls, that says it all. Despite the thin air and needing to rest every ten steps on the energy-sapping lava, sunrise was tapping us on the shoulder and the three of us eventually, happily and achily reached the summit at 3,726 metres. We made it! And Nicola would like it noted that she was one of only three girls that made it up to the summit that day. Some amazing views across the whole of Lombok so (thankfully) definitely worth the extraordinary efforts.

0700 The celebratory water and crackers didn't last long, partly as we were thankful it wasn't fried noodles, but mainly as we realised we had another 9 hours trekking ahead of us to reach the bottom again. In the baking heat, it became the Never Ending Walk. After 12 hours walking from 3am up to the summit till 3pm down in the finishing point of Semabalun, hopes of a comfortable ride home are quashed as we have to crawl into the back of a low-loader and cling on for dear life for an hour through the windy, hilly back roads of Lombok. A tough way to end one of the most challenging treks we've ever done.

The results?

- Three safe returns

- We walked up and down approx 8000 metres in total, which is the equivalent of doing the Three Peaks challenge twice in three days

- Unlike the Russian photographer, our injuries were limited to sunburn, four blisters, dehydration, four bruised hips from sleeping sideways on a hard volcano floor on what might once have resembled a foam mat, and a cut thumb which means James now has blood on his trekking gear which he's very happy about as it makes him look 'tough'

- The inability for our aching quads to now climb the four steps to our hotel room

- Three new Indonesian words unlikely to be helpful anywhere else: snake, monkey and dog

- An acknowledgement from James that we can now splash out on pizza and a room with hot water for the night as a treat. So definitely worth it!