Organic cotton and responsibly produced bamboo are increasingly used in clothing, but sportswear does not yet seem to be able to meet all the requirements without synthetic fabrics.
Do you know how sustainable your sportswear is? In this blog, we clarify what is sustainable yoga by taking mats and clothing as an example to go deeper into the features of sustainable apparel and to help you with making your own conscious choices.
Whether yoga clothing is sustainable or not, depends on many factors, such as the (raw) materials used, the production process of the textile, the transformation of the sportswear during the usage phase and whether it can be recycled or not (Figure 1).
Different raw materials can be used to produce yoga clothing, such as natural materials, synthetics or a blend of the two.
Cotton is a natural fiber which is derived from the cotton plant (Gossypium). For its production, a lot of water and agrochemicals (pesticides, fertilisers, GMOs etc.) are used. Organic cotton is way more sustainable than conventionally grown cotton; its GWP (Global Warming Potential) is 46% lower than the GWP of conventionally grown cotton and also the primary energy demand (non-renewable) is 62% lower (LCA of Organic Cotton Fiber, Textile exchange - 2014). Lyocell is an even more sustainable fiber than organic cotton, since its production needs about 80% less water and the solvent is almost fully reused. Another natural and sustainable material is bamboo. Bamboo absorbs up to five times more carbon than hardwood trees and grows very fast (bamboo is one of the fastest-growing crops on earth). Sportswear made out of natural and organic materials is better for our planet and your skin. Unfortunately, without spandex, natural materials don’t meet all the requirements for sportswear: they are not stretchy and they absorb moisture very well, but dry slowly.
There are many different synthetic fibers used for yoga pants, of which the most common ones are polyester, nylon (trademark: "Supplex" nylon), and spandex (trademark: "Lycra" spandex).
Polyester (polyethylene terephthalate, PET) is basically plastic clothing and requires petroleum (crude oil). It is durable, wrinkle-resistant, lightweight, breathable, and non-absorbent. Since it doesn't dry as quickly as other synthetics, it can make you smell bad (and nobody wants to, doesn’t it?).
Nylon is used to make women’s stockings, it's very soft and it dries quickly. It’s also breathable and it drains sweat from your skin to the surface of the fabric, where it can evaporate. A by-product of nylon production is nitrous oxide (N2O) which is a very strong greenhouse gas with a GWP of 265-298 times that of carbon dioxide (CO2) (Understanding Global Warming Potentials
Spandex makes sportswear stretchy. It's a synthetic fabric which can expand up to five times, which allows you to move freely and it easily snaps back in place. Spandex is breathable, wicks moisture, and dries quickly. The production of spandex requires a lot of energy and recycling it is very hard. It’s also made of polyurethane, which is known as carcinogenic, and it doesn't have a very long lifetime.
Most of the yoga clothes on the market are made out of a blend of natural materials combined with synthetics, such as a mix of cotton, nylon and spandex. The beneficial properties of each material are combined in this way. It sounds beautiful, but unfortunately, clothes with blended materials are almost impossible to recycle. Choosing mono materials for your yoga wear is a more sustainable choice.
Sportswear made out of recycled synthetic materials sounds like a sustainable option, doesn’t it? There is, for instance, the sportswear on the market made from old fishing nets or PET bottles. The answer is, yes, recycled synthetic materials are more sustainable than virgin materials as they need less processing and resources extraction (oil barrel in this case) however, they still release microfibers while using and washing them. These microfibers will eventually end up in our oceans and our food (Figure 2). For instance, one fleece jacket sheds almost one million fibers per wash (Plastic Soup Foundation).
Figure 2: The problem of microplastics
There exist special wash bags, which collect 99% of the microplastics of your laundry. There are also wash balls on the market, but these catches just 5-25% of the microplastics. The best long-term solution would be avoiding buying synthetic clothing and textiles and choosing natural fibers instead.
We just spoke about the environmental impact of yoga clothing, but is your yoga mat really sustainable? There are lots of brands on the market, which offer mats of different qualities and materials. Many cheaper yoga mats are made of PVC and contain harmful chemicals, which you probably don’t prefer to breathe in while you are upside down on your mat. Which materials are safe and sustainable for a yoga mat?
The most common yoga mats are made of synthetic polyvinyl chloride (PVC): a non-biodegradable material that releases toxic gases when burned (as after discarding). PVC also contains the so-called plasticizers. Plasticizers are phthalates which are used to soften the vinyl and to make it sticky and flexible. Research shows that this substance can be associated with the disruption of the hormone balance and that they can be carcinogenic. The phthalates, DBP, BBP and DEHP were included in the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation in February 2011 and were phased out by the EU by February 2015.
There are also yoga mats on the market made out of Thermoplastic Elastomers (TPEs). TPE is a synthetic type of rubber and it’s a relatively new material for yoga mats. TPE has mysterious origins since it is an umbrella term for anything from plastic to mixtures with rubber. Yoga mats made from TPE are free from harmful toxins and hypoallergenic. They are also easy to recycle, softer than PVC and lightweight. The claim is often that they are 100% biodegradable, but let’s put some question marks here. Biodegradable is not always biodegradable; a product won’t always decompose and go back to where it came from. Materials such as PLA, PPC and PEC can be “biodegradable” only in special circumstances, such as high temperatures (50-60°C) and in the presence of water, which is only possible in specially equipped facilities. Even if it is an actual biodegradable product, it is still a synthetic product, which is manufactured using heat (which requires lots of energy) and undergoes many chemical processes. The average lifespan of TPE mats is about 5 years.
One of the natural materials a yoga mat can be made of is rubber. It comes from the rubber tree and it is a biodegradable material ideal for yoga mats production because of its natural resistance and grip. Natural rubber sounds like a wonderful alternative to PVC, where it’s not for the fact that its lifespan is only one year.
Natural materials aren’t always more sustainable than synthetics. The origin of rubber is difficult to trace, its production process is polluting and the working conditions in the plantations can be poor. Sometimes, rainforests are cut down for the production of natural rubber and, besides that, most of it travels a long way from Asia and South-America to Europe.
If you’re looking for a good label for rubber, the FSC label (for fairly managed forests) is reliable, but not always linked to rubber products. Ethical sportswear brands exist, including fair trade certification.
Another natural material which is used for yoga mats is cork. Cork is the bark of the quercus suber tree, which grows primarily in countries along the Mediterranean coast (since they need plenty of sunshine, low rainfall and high humidity). The trees don’t have to be cut down for the harvesting of cork and the bark just grows back in about 9-12 years.
Cork absorbs moisture really well and becomes extra stiff when you sweat. It also has anti-microbial properties. The material is strong, natural and clean. Trees absorb CO2 from the air, which makes a cork yoga mat the most sustainable option for yoga mats in terms of emissions (natural CO2 offsetting!). Moreover, when cork bark is harvested, it enables the tree to absorb up to five times more CO2. For more grip on the floor, cork yoga mats usually have a layer of TPE on the bottom, but there are also mats available with a layer of natural rubber.
So, where should you buy your sports apparel? First of all, only buy new items if you really need them. Second-hand options which offer eco-friendly alternatives are also available in the market and vintage sales are always more popular. But if you’re really looking for pragmatical tips, you should always look for:
o Certified, organic and natural materials;
o Production under fair conditions;
o A traceable supply chain, preferably close to home;
o A transparent brand;
o The durability of the product
