Alan Hinkes takes you through his clothing system for High Altitude Climbing

What does it take to scale the world's highest peaks?
Mountaineering expertise, plenty of bottle and stacks of gear. Alan Hinkes takes you through it layer-by-layer, from top to bottom.

Climbing 8000m peaks is dangerous. One of the dangers is the cold - extreme cold. 40 below is common. In fact, extremes of temperature are possible at altitudes of up to 7000m, and it is possible to get a 'false ambient temperature' of +40C, which is more than 100F.
On extremely rare windless days, the sun can burn and heat up the surface air in sheltered locations, making it feel like an oven in the rarefied air. But generally the problem at altitude is protection from the cold. The best way to keep warm is to layer up. Layering also gives versatility - as it becomes colder you can put on more layers - 'the way to keep warm is to keep cool'. Don't over-heat, strip layers off if you become too warm - I'm often stripped down to my base layer, which then becomes an outer layer. The layering principle traps air, and still air insulates. Sweat cools, so a wicking layer next to the skin is best, to transport the moisture to the outer layers. The middle layers insulate - for 8000m peaks, I use a combination of Polartec and down garments. The outer layer cuts out the wind and anything windproof works - I use Activent at the moment, but have used Gore-Tex and Pertex in the past. All the layers I wear are available from outdoor retailers, except the one-piece down suit, Neoprene overboots and 'Hinkes Suit' (a one-piece oversuit).

Skin is waterproof and breathable, it regenerates and lasts forever. It does go wrinkly with time, soft and wrinkly if wet for too long, and it's easily rubbed off and burns in the sun. This layer can be worn in the bath, on the beach or in the office.

Watches (left wrist): Casio ALT6000 - alarm, date, stopwatch, temperature and altitude to 6000m. The alarm's useful for those pre-dawn starts, but it works better with the watch dangling above my head in the tent - on my wrist, buried in my sleeping bag, it's not possible to hear the alarm. I use the stopwatch to monitor my heart rate, to check my acclimatisation - the slower my pulse the more acclimatised I'm becoming. The temperature reading's interesting because it has to be hung in the tent to get an air temperature - on the wrist it gives wrist temperature. The date helps me keep track of time as the weeks pass by at altitude! Watches (right wrist): Avocet Vertech - takes over as an altimeter when above 6,000m and up to 10,000m. But how do you test it goes that high?

Speedo swimming trunks - tough-wearing, useful for a quick dip (I also wear ordinary M&S cotton 'shreddies'). Around my neck is a Buddhist Puja necklace, a piece of cord with a knot blessed by a lama or monk - mine has an extra tassle, allegedly blessed by the Dalai Lama, and I must get round to taking it off as I'm neither superstitious nor Buddhist.

This is the next-to-the-skin wicking layer which keeps you warm by keeping you dry. It also acts as a protective layer against the sun. I use high protection sunscreen, at least factor 15, usually 20-25 plus. Worn up to 5500m, possibly 6000m in very good weather. Berghaus ACL Shirt and Berghaus ACL Pants - I generally wear these two items next to the skin, under other layers. It has a soft feel and a loose enough fit to make it comfortable. It can get smelly when I've worn it a long time - fresh smelling clothes are not the norm on Himalayan expeditions - and I sometimes wear it for two weeks or more, but usually try to wash it at 7-14 day intervals. Even in base camp, hot water for washing is a luxury, so I often use cold water. Sometimes when I hang my ACL out to dry it just freezes, even in the sun. I take at least two sets of ACL on an expedition, sometimes three and I may even wear two layers of them at times. Loopstitch socks - I only wear one pair of loopstitch (Berghaus Mountain or Terra Nova Toasties) but take five or six pairs on an expedition. Clean socks are warmer so I do wash them out, as with the ACL, and ensure I keep a new, clean pair for the summit push.

This layer is worn up to 6000m, possibly 6500m-7000m in very good weather. Up to 6000m, I may be moving relatively quickly, and creating heat, so this layer can be enough in good weather. This layer isn't windproof so I would wear my Berghaus Extrem Gore-Tex jacket and salopettes up to 6000/6500m, or my one-piece 'Hinkes Suit'. Berghaus Activity Jacket (Polartec 200) and Berghaus Microfleece Pants (Polartec). High altitude inners for Scarpa Vega plastic boots - made from a closed cell foam called Alveolite. This is light, with good insulating properties (the little bubbles in it trap air), but it's a vapour barrier non-breathable material so my socks and feet get wet with sweat. I carry spare, dry socks to put on at night; the wet ones are put under my arms to dry. I mark my inner boots and outer shells 'L' and 'R' with a permanent marker (see Layer 7) - I used to get ribbed for doing this, but I notice more and more mountaineers are copying me. Ordinary plastic boot inners can be a little heavier and some absorb sweat. I would then have to dry out the inner boot as well as the socks.

Above 6500m, it's still very cold, even in good weather. The air is very thin and blood gets thicker with dehydration caused by gasping in the rarefied air. This layer can be worn above 6500m, up to 7500m, in good weather. Scarpa Vega plastic boots - I wear one size bigger than I would in Scotland in winter, or in the Alps. This is to allow for swelling (oedema) at altitude and so I can wriggle my toes to keep my circulation going in my feet to help prevent frostbite. Berghaus Mountain Spire hat (Polartec) Terra Nova Thinnies gloves - gives basic protection when handling cameras and also protects from the sun. Mountain Equipment down vest - this is very light and compact, packing down to the size of a pint pot. It keeps the main body core warm, and there's excellent freedom of movement. Vuarnet sunglasses - essential glacier-type eye protection. Dermatone sunscreen.

Mr Michelin man, but its all essential above 7500m and into The Death Zone (8000m+). I need all these layers above 7500m because extremes of cold are the norm, even in good weather. One-piece down-filled suit (Pertex covered) - this is light because of the down and cut loosely for freedom of movement, with zips under the arm. These full-length zips allow the side of the leg and body to completely open for ease of putting on and getting off, and for going to the toilet. No need for a 'crap flap' zip opening at the back.

Berghaus Mountain Spire hat (Polartec).
Smith goggles - sunglasses can freeze with vapour from my breath, even in good weather. In bad weather, at high altitude there is still a lot of UV. Goggles are essential to protect my eyes from the radiation and spindrift. Sometimes I use goggles with clear lenses in Scotland in winter to protect from the stinging spindrift.
I also use Vuarnet goggles and Extremities insulated gloves.
Berghaus Yeti Gaiters - not insulated but give an extra layer and prevent snow entering the boot. Marked with 'L' and 'R' so it's easier to see which is which without using too much brain power - I also write 'Hinkes' on mine in case I forget who I am.