Cotton As A Base Layer: Good Or Bad Idea?


Much has been written about cotton in clothing. Whether good or bad, the fact remains, cotton will always be used in garments one way or another, as it is soft, non-itchy, breathable, and durable. However, does it work as a base layer?

If you are an outdoors person, an athlete, or if you live in a cold climate, you will understand the benefits of layering your garments in such a way that you can add more on if you are cold and need to get warm or take something off if you are too hot and need to cool down.

Cotton fabric is not ideal as a base layer for hiking or other outdoor activities. When cotton becomes wet from your sweat, the air pockets in the fabric fill up with moisture and can become saturated, which means you lose your insulation. Additionally this means your sweat isn’t evaporating as efficiently.

Wearing many different layers of clothing at one time is something that we all do at some stage in our lives. Finding a good fabric for a base layer is all-important as you need to be able to keep yourself warm, while at the same time not overheating or having a damp layer against your skin because of a fabric that does not wick away moisture.

Does Cotton Work As A Base Layer?

Cotton is not ideal for a base or foundation layer against the skin in cold weather. Cold-weather clothing keeps you warm through insulation. Insulation typically works by trapping the air warmed by your skin from escaping which helps you retain your body heat.

When hiking, cotton soaks up moisture and draws all the heat away from the body, which leaves you feeling cold because the air can no longer be trapped and you don’t have protection from the cold weather!

Cotton can work fine as a base layer in mild weather.  If you’re hiking or otherwise adventuring in 60-75 degrees Fahrenheit weather in non-humid conditions, your clothing won’t stay saturated and your cotton shirt will stay comfortable and will work fine. 

Cotton is not ideal for hot conditions as a base layer. If you’re hiking or exerting yourself, you’re going to sweat. If you live in Texas, then you’re going to sweat just being outside. Cotton has almost no moisture-wicking capabilities and is generally heavier than synthetic fabrics. It will absorb and retain heavy amounts of moisture, leaving you uncomfortable and lugging around a soggy base layer against your skin.

Now, this is where it can be a bit confusing—since people actually use wet towels to cool off in warm weather, why wouldn’t a cotton t-shirt be the best type of base layer? 

The answer is that it is complicated by a lot of factors:  the thickness of the fabric, the outside humidity, and how much you sweat among some.  If the fabric is thick enough, for example, then the water is not going to evaporate quickly enough to keep you cool.

From personal experience, I’ve worn cotton shirts in very hot conditions and I’ve not had a terrible experience.  If, however, you are trying to use cotton as a base layer while exercising in hot weather, then I wouldn’t use cotton because all that sweat is going to stay with you. 

Cotton can absorb as much as 2700% of its own weight in moisture, while polyester absorbs up to 0.4%. Merino wool 33% and silk 30%.

Counter-Argument: Perhaps Cotton As a Base-Layer Isn’t So Bad

So I’ve been doing a lot of research about cotton and base layers over the past several months, and I found an extremely interesting study that has a different perspective on cotton as a base layer.

Essentially, the study finds that a wearer often cannot tell the difference between cotton, wool, or polyester base layers. The most important thing is not the material itself, but rather the thickness of the material!

Additionally, another finding is that whether a base layer is cotton, wool, or polyester doesn’t change out much water the base layer absorbs, but rather the thickness of the material.

Now it’s still possible that cotton base layers are not the best idea for extreme cold conditions, but one perspective is that your layering system matters far more than the material type, as well as the insulation properties of the mid-layer and the impermeability of your outer shell.

I’ll continue to explain the concepts as they are generally understood and hopefully you find this helpful.

What Is Moisture-Wicking?

Moisture-wicking refers to the fabric’s ability to quickly move (wick) body sweat to the outer surface of the fabric and then to dry rapidly so that the fabric does not remain saturated with sweat. In other words, to move the sweat off your skin.

Moisture-wicking fabrics have the ability to move liquid such as sweat through the tiny spaces within a fabric. For use as an under-garment layer that touches your skin, look for labels on fabrics that advertise moisture wicking.

The best moisture-wicking fabrics are synthetics such as nylon or polyester, as they are water-resistant and are excellent moisture-wicking fabrics as opposed to cotton which is generally considered as non-wicking.

Can You Use Cotton for Hiking?

You can absolutely use cotton for hiking.  If you’re in cold-weather conditions, though, I’d really recommend another fabric for your base layer. Layering your garments using a combination of wicking fabrics and insulation fabrics is the best way of keeping warm during a hike.

For myself, I have been using a polyester base layer to great success.  My Coldpruf (Amazon) dual-layer thermals that I’ve had for a few years are very warm but not uncomfortably so (unless it gets above 70 degrees Fahrenheit).

Another excellent base-layer fabric against your skin is merino wool. Merino Wool, even though it does not wick like synthetic fabrics, is breathable and should be used as a thick layer of insulation, which will keep you dry and warm.  Wool also retains a lot of its insulation properties when it gets wet, which is crucial in colder weather.

An added benefit of merino wool is that it is odor resistant, which is useful on long trips. Wool has the great ability to hide dirt and grime and has the additional added benefit of being fully dry within 45-60 minutes while being worn on a sunny day.  I can attest to this with my merino wool socks—they stay really warm and they also dry quickly.

What’s So Bad About Cotton?

To summarize the issues with cotton, you can boil it down to three basic points:

  • When the cotton garment gets wet from sweat, all the air pockets in the fabric are filled with water, thereby losing its insulation properties.
  • Once wet, cotton does not dry out quickly.  If you are wearing a cotton-shirt, it will dry out in an hour or two if it’s exposed to the air—but if your cotton socks or cotton base-layer gets wet, it’s going to stay wet for a while.

If the outside atmospheric temperature is much cooler than your body temperature and your cotton garments are saturated with sweat, you will feel cold and wet. This could lead to hypothermia and potentially worse consequences.  Cotton kills is a modern axiom.

That being said—if the weather is mild, cotton will work just fine.

Ideal Layering System for Cold Weather

The best measures you can take to protect yourself from the elements in cold weather is to wear three separate layers. Each layer has its own unique purpose – to wick sweat away from your body, keep in the heat, and to keep out the cold, wind, and rain.

Layering begins by focusing on the layer that touches your skin – your underwear. Comfort begins with your foundation layer.

  1. The fabric that you choose is your most important decision – whether you chose a synthetic or natural fiber, it needs to wick well!
  2. Choose either a lightweight, midweight, or heavyweight fabric depending on the level of warmth and comfort that you require.  I wear relatively heavyweight thermal underwear in temperatures below 45 degrees Fahrenheit (because I’m a cold wimp)
  3. A snug fit is an important factor when choosing a wicking fabric, as it needs to be in direct contact with your skin.
  4. Long thermal underwear is a comfortable option for a base layer.

The Base Layer

The base layer is the underwear layer (in contact with your skin), and its purpose is to wick the sweat off your skin. The base layer comes in different weights, which are determined by the activity that you are taking part in, and on the temperature:

  • Lightweight – moderate to cool temperatures. The thinner the fabric, the better it will wick, and the faster it will dry. Outdoor athletes such as long-distance runners will generally use a light layer against their skin as it dries quickly. In colder climates, for example, a cross country hiker may combine base layers and wear a lightweight shirt under a midweight or heavyweight garment.  I should mention that it hasn’t been definitively proven (with any study that I’ve been impressed with at least) that base-layers can keep you cooler than no layer at all. 
  • Midweight – cold temperatures. This midweight fabric can be used on its own or as an additional layer over a lightweight fabric providing insulation and moisture-wicking. This fabric would generally be worn in colder temperatures.
  • Heavyweight – below freezing temperatures. This fabric is designed for extremely cold temperatures and is not typically worn as a first layer but rather over a light or midweight base layer purely for insulation. Moisture-wicking is not a priority for this fabric.

Although you may not wear all three layers at once, make sure that you do have various garments with you at all times. If you overheat, you can take garments off, but if you are cold, you can only put on the garments that you have with you, so be prepared!

The Middle Layer

The primary purpose of the middle layer is insulation. This is the layer generally worn over the base layer and beneath the outer layer. You might wear more than one middle layer at a time if the weather is cold enough.

For the middle layer, thicker equals warmer, but the insulating material is also very important.

  • Polyester fleece is available in lightweight, midweight and heavyweight fabrics. Fleece breathes well and stays warm even if it gets damp.

The downside to fleece is that the wind blows straight through it, reducing the heat which you have already built up against your skin. A better option would be to wear wind fleece, which has a built-in wind-blocking membrane – or you can wear a heavy outer layer over the fleece.

  • Down insulated jackets are highly compressible and offers more warmth for its weight than any other insulating material. A down jacket does offer some water and wind resistance but can lose its insulating efficiency when it gets damp, so make sure it is covered by a shell material.
  • Synthetic insulated jackets do not compress as well as down, but they do retain their insulating ability when they get damp, so they are a good choice for rainy conditions.

A broad base of options is available, depending on your needs and requirements. Wool and wool-blend tops are a good option for hikers.

The Outer Layer

This is the shell layer, designed to protect and shield you from the wind and rain. This is an item that can be quite pricy, especially for mountaineering jackets, but can also be more affordable such as a wind-resistant jacket. Most jackets will be treated with a durable water repellent finish, which causes the water to roll off the fabric.

An example of a shell is the Columbia Watertight II jacket (I got it from Amazon years ago).  I’ve taken this jacket to New Zealand twice and it’s been a phenomenal shell that has kept me warm during chilly rain.  It is non-breathable, but it does have venting capabilities.

  • Waterproof/breathable shells are at the top of the range and can be quite pricy but are the best option available for extreme weather conditions and often more durable than the lower-priced jackets.
  • Water-resistant/breathable shells are made from a tightly woven nylon or polyester fabric that keeps you dry and warm in light wind and rain. As they are a bit lighter than waterproof shells, they are more conducive to high-level activities.
  • Softshells feature stretch fabric or fabric panels and emphasize breathability. This jacket combines light insulation with light rain and wind protection.
  • Waterproof/non-breathable shells are made to be used on little to no-activity days, think fishing! This jacket is made from a coated nylon, which is water and windproof, so if you do exert yourself while wearing this jacket, your underneath layers will probably be saturated with sweat! Sometimes these shells have vents that you can zip open to mitigate some of that non-breathableness.
  • Beanies, gloves, and scarves are sometimes overlooked, but make sure that you do have one of each tucked away in your pack.

Decide what you can comfortably afford for the terrain that you will be hiking through.   

Recommended Fabrics for Cold Outdoor Layering

Choosing a base layer for hiking means using a fabric that will suit your adventure! Choose a fabric that will absorb moisture and keep you dry at the same time! Your base layer should be form-fitting and warm, as well as providing comfort to the wearer.

  • Synthetic materials score a 5/5 for wicking properties, a 4/5 for durability, and a 3/5 for odor-resistance – Nylon, polyester, or a polyester blend. Perfect for a cozy, snug fit against the skin. Polyester is the best fabric for long underwear, while spandex offers some stretch for extra comfort.

Synthetics fabrics are the most durable and long-lasting.

  • Merino Wool scores a 4/5 for its wicking properties, 3/5 for durability, and a 5/5 for being odor-resistant! – Wool is lightweight and gentle and soft to the skin and can absorb a huge amount of moisture. Wool is breathable, providing excellent temperature regulation even though it will take a little longer to dry when it gets wet. For increased durability, try a blend of synthetic and wool.
  • Silk only scores a 2/5 for wicking, durability, and odor retention– Designed for colder temperatures, silk slips easily under other layers, is silky smooth, and feels great against the skin! As it is not odor resistant, it will need to be laundered after each use. 

Which Fabrics Should I Avoid As A Hiker?

Firstly, avoid any fabric which states “non-wicking”! Fabrics labeled as corduroy, denim, flannel, or duck, as well as cotton-polyester blends are not ideal–these are all made with cotton. Keep away from cotton/polyester blends that are not at least 85% polyester!

These fabrics are a big no-no as they absorb water even faster than cotton and lose all of their insulation when wet.

  • Modal
  • Rayon
  • Viscose
  • Tencel
  • Lyocell

Steer clear of clothing made with bamboo – many bamboo products are a type of rayon and have the same absorption and insulation problems.

No Hope for Cotton?

The performance of cotton is constantly enhanced through technological innovation, which seeks to reinvent cotton as a true performance fiber. Currently, cotton is being engineered to manage and repel moisture at the same level as top performing synthetics.

Through new wicking technologies, moisture management is being taken to a whole new level with endless possibilities, including sweat hiding technology.

A new water repellent technology designed specifically for denim keeps jeans fresh and clean no matter which activity you are involved in – hiking, skating, biking, and even casual wear.

Cotton manufacturers are introducing new technology using synthetic blends with cotton to improve cottons’ usefulness in the outdoor activewear market, but the technology has not got to the point where it can compete with the pure synthetic materials.

Conclusion

So, is cotton fabric used as a base layer of clothing a good or a bad idea? The answer is not as basic as it may seem, since people have their own preferences for each fabric and how many layers they will wear at any one time.  So, it may take some experimentation to find out what works for you,

One good rule is to dress in layers every day to not only keep you warm and dry while you walk but to also keep you comfortable while you enjoy the great outdoors.

References:

www.cotton.org

https://www.cottoninc.com

https://sewport.com/fabrics-directory/cotton-fabric

https://cottonsa.org.za/2016/03/10/the-many-many-uses-of-cotton

https://www.rei.com/blog/hike/what-does-moisture-wicking-mean

https://www.rei.com/learn/expert-advice/underwear

https://www.rei.com/learn/expert-advice/layering-basics

https://www.ems.com/how-to-choose-a-base-layer

https://sectionhiker.com/why-does-cotton-kill

https://sectionhiker.com/wool-vs-synthetic-which-is-the-better-baselayer/

https://besthiking.net/comparison-of-base-layer-materials/

Peter

Peter is a software developer who loves to take every opportunity to go outside that he can get. Peter grew up going on long backpacking excursions with his family every Summer and now enjoys staying at the beautiful Texas State Parks and swimming in the amazing Texas Rivers.

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