Baselayers

Merino in the Cairngorms

I used the same excellent Merino long sleeved baselayer each day on a recent trip without it developing an odorous odour. Temperatures ranged from a summery 20'C to -15'C wind chill on the summits.

Other clothing worn included:

• FurTech trousers (comfortable even at 20'C with the sides fully open)

• MultiTube (for neck and face protection)

• FurTech Claw2 jacket (sometimes with arms out of the sleeves)

• OD WindiUsh hat

• OD Taku Stretch gloves

• OD Event insulated glove

• RAB Belay jacket (for lunch stops)

• Various socks and mini gaiters with boots or Inov8s, including X-socks and Seal Skinz

Baselayers with Collars?

Collars can add a bit more insulation and provide sun protection. Another alternative is to use a Multi-Tube as a removable collar (which can be used for so much more).

Click here for more details of our Multi-Tube.

Wind Resistant Baselayers?

For me baselayers should be suitable for a wide range of conditions. When it's hot they provide wicking and sun protection; when it's cold they provides insulation. Unfortunately wind resistant base layers reduce breathability and ventilation making them less suitable when you are trying to stay cool.

Conventional base layers are also easily uprated with a lightweight WindShell or other layers and they allow good air flow through the vents on outer jacets.

Cotton Baselayers?!

The reason that cotton baselayers are potentially dangerous in cold and temperate mountain environments is that they hold water next to your skin, significantly increasing your chances of hypothermia!

A wet cotton T-shirt can easily double its weight when wet. The water gets absorbed into the cotton fibers and the gaps between them, displacing much of the air and causing the garment to stick to your skin. Water conducts heat 24 times faster than air and absorbs enormous amounts of heat as it dries.

Cotton trousers are equally as dangerous. In the UK hills, even in the summer, saturated cotton clothing can have a dangerous chilling effect should you be caught out. Jeans are especially bad as denim is thick and absorbs a massive amount of water.

Two Shirts, Two Weeks, Too Light?

I took just 2 GoLite T-shirts on our recent 2 week trip to the Dolomites and they worked very well indeed. The quick drying time was very useful as I'd wash one in the evening and it would be dry by morning (similarly 2 pairs of X-socks).

The trip also reminded me that traveling light doesn't just mean weight off your feet, but is useful when fitting a load of camping and climbing kit into a budget airline's baggage allowance!

Synthetic Baselayers?

Synthetic fibers don't absorb much water and are often adapted with a hydrophilic surface to enhance wicking. Because of the low water absorption they dry quickly.

Unless treated with an anti-microbial mechanism (eg silver or carbon) synthetic fabrics can soon become very smelly. However, they may be able to be washed and dried over night.

Denier Gradients

A denier gradient describes how the thickness of the fibers change from thick to microfibers, from one face of the fabric to the other. Synthetic base layers are often constructed in this way in order to enhance their wicking properties. This works because of the increased surface area available in the microfiber bundles compared to the thick ones, and the increased number of channels for wicking. As water evaporates off the outer microfibers the liquid water is drawn outwards along these capillaries. The effect is improved by altering the surface tension of the material during manufacture.

1 denier means that 9000m of the fiber weight 1g. A 1 denier polyester fiber has a diameter of about 10 micrometers! A human hair is between 20 and 150 micrometers wide.

Click here for more on capillary action.

Merino Wool Baselayers?

Merino wool baselayers have found favour in recent years. They offer natural odour resistance and can be worn in a surprising range of conditions.

The fine merino wool absorbs water into its core but presents a scaly less absorbant sheath to keep the moisture from your body (unlike cotton). The hydrophilic nature of the core means they don't dry as quickly as synthetic fibres, but feel warm when damp. The core could be seen as being breathable, absorbing and releasing moisture, so that the garment as a whole offers more breathability, and therefore more temperature flexibility, than a synthetic baselayer.

Bacteria find it difficult to live on the surface of the wool fibres so that they have a natural antimicrobial effect and don't smell after prolonged use.

Because Merino fibres are finer and softer than wool from other types of sheep they don't itch and scratch and are comfortable when worn next to the skin.

Click here for our bargain Merino Long Sleeved Top.

Thick or Thin Baselayer?

This very much depends on the temperatures and activity, but consider that base layers can be layered for extra warmth, or swapped when one gets wet.

Thick baselayers with brushed inner surfaces tend to trap air in the fur next to your body and can feel much drier than "flat" fabrics. This is especially the case if they have some sort of enhanced wicking process such as denier gradient technology. The thicker fabrics can also absorb more moisture before becoming saturated. However, once completely wet most fabrics feel pretty much the same and performance then depends on how quick the inside dries.

Very thin or mesh like baselayers may not provide sufficent UV protection on their own.

Considering a Baselayer?

For me the most important aspects of base layers are:

1. Comfort
2. Drying ability (combination of wicking, fiber type etc.)
3. Air permeability and breathability (pretty much the same thing for these fabrics)
4. Appropriate insulation for the conditions
5. Odour resistance
6. UV protection (in the summer)
7. Durability

Baselayer: the most important layer?

I have heard it claimed that the base layer is the most important layer. Others say that technical base layers are all pretty much the same. While these statements aren't necessarily contradictory, it seems clear to me that layers can't be considered in isolation, they are part of a system that for me includes FurTech, OverShells, Shelters, emergency insulation and even the sack.... and in the summer a layer of sun tan lotion!

The breath ability of the whole clothing system has a big impact on how a base layer performs. This is because it limits how quickly moisture can evaporate away and how soon the baselayer dries. This is especially evident beneath a sack, where breathability is usually poor.

GoLite DriMove Cocona Review

The new Go Lite DriMove is rapidly becoming my favourite T-shirt! I used it, washed it (to see if the smell absorbing technology would be removed) and wore it again. Today is my 4th day of wear including rock climbing and a 16 mile, 20'C, sweat dripping hike... no smell!

The carbon (extracted from discarded coconut shells - Cocona) is apparently permanently bonded to the polyester fibers. This absorbs and traps odours, gives the thin fabric a sun protection rating of UPF50+ and enhances wicking.

The advantage of synthetic base layers has always been that they dry quicker than natural fibers, and they are far cheaper and lighter than merino wool. GoLite claim that their fabric moves moisture "over 50% faster than all leading polyester moisture management fabrics so you stay drier and cooler". A big claim!

It worked well under a GoLite Ether WindShell during a few drops of rain (20'C) and beneath a FurTech jacket with the Rain Vents open. If you are likely to get wet in warm rain, perhaps when wearing a WindShell, synthetics make more sense than merino wool as they dry faster.

Ultra Violet: UVA, UVB, UVC

Ultra Violet Light can be classified into three types: A, B and C. These have different wavelengths and penetrating effectiveness:

• UVA 400-320nm penetrates weakly and is the least dangerous and can be seen by some animals
• UVB 320-280nm can cause skin and eye damage
• UVC <280nm penetrates strongly

Because of the ozone layer, 99% of the UV that reaches the Earth is UVA. The UV Index is an international standard to indicate the amount of UV reaching the surface on a particular day.

Ultraviolet can cause skin to burn and will disrupt DNA, causing cancer. Browning of the skin is the bodies mechanism for protecting the deeper layers from UV damage.

90% of UV greater than 300nm is passed by ordinary glass, which blocks 90% of UV below 300nm.

Snow, sand, water and even grass can reflect UV and increase your exposure. Clouds reduce (but don't eliminate) UV and in "top of the cloud" conditions may increase your exposure. At altitude, UV exposure is greater because there is less atmosphere to filter out the rays.

SPF and UPF

The Sun Protection Factor generally refers to sunscreen. The Ultraviolet Protection Factor was developed in Australia to indicate the sun protection offered by clothing.

UPF 50 means that only 1/50th of the Ultraviolet falling on the surface of the fabric will pass through. Garments are rated as UPF50+ when they block more than 98% of the ultraviolet radiation.

There may be double the ultraviolet radiation above snow and the thin air at altitude provides less protection.

Wind Shells for Midge Protection

Culicoides or the infamous Midge are the bane of summer walkers and climbers in many of the moorland areas of the British Isles. Apart from using a good midge repellent (Avon body lotion!), consider using your Windproof jacket for protection.

Soft Shell or Wind Shell plus Baselayer

There are a number of bicomponent soft shells on the market, which are designed to be worn next to the skin as a single layer. The first of these was Buffalo's pile pertex, then thinner and less insulating designs came along from Buffalo, Marmot, Montane and Rab, amongst others. For me the advantages of this type of kit are

1. Can vent to the skin with minimum fuss
2. Warm when wet (they usually have a furry lining which traps more air than water next to the skin)

However, the alternative is to use a base layer beneath a WindShell. This option provides

1. Flexibility, because the windproof can be removed for warmer conditions.
2. You can select the type and thickness of the baselayer as appropriate for the conditions (including furry ones for winter, T-shirts for summer or multiple layers).
3. You can wash them separately, maintaining the water repellency of the windproof with an easy to apply wash in product and washing the baselayer conventionally as often as is needed.
4. The base layers can be used under other waterproof garments without need for the windproof (improving the breathability of your layering system).

(FurTech jackets will help dry a wet WindShell or SoftShell, unlike thin membrane garments. For most conditions they can be used as a softshell, over a baselayer.)

Baselayers for Sun Protection

The degree of sun protection provided by your base layer depends on several factors:

1. The type of material used (polyester, wool, etc.)
2. The density and thickness of the knit
3. Any treatments that may be provided
4. Colour
5. If they are wet or dry
6. How worn (damaged) they are
7. If the fabric is stretched

The thickness and density of the knit block out the sun light and an indication of their effectiveness can be gauged by looking through the fabric against a light. However, the material that is used and how it is treated can have a significant impact on sun protection. This is because some materials reflect or absorb ultra violet light. For example activated carbon bonded to polyester is effective at absorbing UVA and UVB in the GoLite CoCoNa products and Granger's have a wash-in product designed to enhance sun protection.

Please also remember that when fabrics get old and thin, or wet, their sun protection value diminishes and it may be worth using a sun lotion beneath your old T-shirt for protracted exposure to intense sun.

Here's more about CoCoNa and an entertaining and informative article by Andy Kirkpatrick.

Baselayers and Windproofs in the Hills

Occasionally I use a hooded windproof for summer hills. They are very breathable, very light and very comfortable. With good Durable Water Repellancy they cope with a surprising amount of rain, though if you are sweating inside this tends to draw water in.

As conditions worsen wind proofs can be reinforced with a FurTech jacket, an OverShell or Blizzard Jacket. FurTech jackets are very effective at drying off a wet wind shirt.

(The breathability of a membrane waterproof hardshell may be overwhelmed when layered over a wet windproof!)

Baselayers and Windproofs for Running

I've spent many a happy hour fell running in a baselayer and hooded windproof, in the rain... and many hours running in lightweight waterproof breathables. Their performance is very dependent on the effectiveness of the water repellency.

Good repellency on a windproof can cope with a surprising amount of rain, but when it wears off, water gets in. However, if you are working hard and sweating, what difference does a little more water make?

This system works well with fairly constant high energy output. When you stop you will chill rapidly - far more quickly than when wearing a waterproof breathable - so you should consider carrying extra protection.

My emergency protection for fell running now includes a Blizzard Vest, which weights a paltry 250g and easily fits in a bum bag. However, for a long time I carried a plastic bin bag on the basis that I could tear holes in it and wear it over the windproof... and limp off the hill, Touching The Void style. (I never used it, but did once use a bin bag as a jacket in a cave, when I forgot my waterproof, and was surprised that it lasted the 2h trip through wet narrow passages.)

On the other hand, waterproof breathable garments virtually stop breathing when the repellancy wears off, so you get wet from condensation anyway... and much of the time they aren't breathable enough to cope with the sweat you produce. I've seen condensation trickling out of the sleeves of some high tech running jackets.

All fell races and adventure races, that I am aware of, specify carrying waterproofs. Windproofs aren't acceptable, contrary to the opinion expressed here.

GoLite C-Thru Baselayer

This link to OutdoorsMagic provides an independent review of the excellent GoLite C-Thru top. More information is available at our web shop.

There is also a summary of baselayer technology here.

ProSkin Smells Less

After repeated washing and wearing the anti-microbial effect hasn't been removed from my Proskin top. I have experienced anti-microbial treatments on other garments that have only lasted one wash!

Wicking and Temperature Gradients

Sweat evaporates from our bodies in order to cool us down, absorbing massive amounts of heat energy from its immediate surroundings. Its rate of evaporation is effected by several factors:

• If the temperature is increased, it evaporates faster.
• If humidity is reduced, it evaporates faster.
• If the pressure is reduced, the wind blows across it, or breathability is increased, it evaporates faster.
• If the sweat is spread out, its surface area increases for faster evaporation.

How the temperature varies from skin to exterior can be called the temperature gradient: it is usually significantly warmer on the inside and cooler on the outside.

It therefore makes sense to evaporate sweat directly off the skin as this is what requires cooling and is also at the warmest end of the temperature gradient. In fact, wicking sweat away from the skin (as many manufacturers advocate) would only make us cooler if it was being moved to a part of our clothing system with lower humidity or better breathability. In some thin clothing systems for sunny weather this is possible, but in windproof systems the humidity and breathability is typically constrained by the windproof (often waterproof/breathable) barrier, on the outside. This is why breathability and venting are so important.

When evaporation of sweat is slowed, cooling is degraded, you sweat more and the clothing system becomes damp. Wet clothing insulates less because conduction is increased, but this doesn't cool as effectively as evaporation, and continues to chill for some time after you stop. Sweating more also contributes to dehydration.

Some baselayers seek to spread or wick sweat across the skin for better cooling and faster drying, notably those made by Paramo, the GoLite C-Thru Lite and ProSkins. ProSkins fit like a second skin for especially effective cooling and drying. They don't feel too bad when they are wet because movement doesn't bring you into contact with a cold patch.

Thicker baselayers with brushed linings are often designed to wick moisture from the skin and keep you warm and dry (contrary to why you are sweating in the first place). This may be important if your shell doesn't breathe or ventilate well and can provide an absorbent buffer beneath your sack where evaporation is usually poor. On the other hand, thin baselayers that wick across the skin pull sweat to the sides of your sack and towards your vents, allowing it to evaporate away.

If you are serious about staying warm in the mountains make every effort to avoid sweating. Making steady progress, rather than short, fast bursts helps. Don't wear too much. Use the vents in your clothing and remove layers when they aren't needed - hats are usually easy to take off. Consider starting out cool, with minimal layers, but take an OverShell or Shelter to wear when you stop.

MRSA Contraception

For centuries silver has been successfully used against bacterial attack. In the past silver coins were placed in earthen vessels to preserve milk and silver spoons may have had practical benefits for well born babies. Today the inside of refrigerators are made of silver-containing coatings to meet hygienic requirements. It is also used in medico-technical plastics. In textiles silver has recently been used in a number of ways: as fine silver wire, vacuum-metallised on the fibre or as a top finish on fabrics.

Silver has 3 main effects on microorganisms such as bacteria and fungi:

1. Blocking oxygen-transporting enzymes
2. Inactivating sulphur-containing proteins of the bacteria
3. Locking the cell membrane

Because the cells can't multiply, it has a contraceptive effect, even on the deadly super-bug MRSA (though it doesn't kill it outright).

I hope you don't need protection from that. However, bacterial degradation of perspiration leads to body odour and fungal foot infections can be a problem. Bacteria can also cause allergic reactions and, obviously, infections. All dealt with by a silver bullet!

Forgetting the medical benefits, for me, anything that reduces the pong after a hard day in the hills is worth its weight in er...gold!

(The FurTech lining and ProSkins baselayers have silver anti-microbial treatments.)