Wrapped in Plastic: The Hidden Chemistry of Modern Sportswear and What It Might Be Doing to Our Bodies

There is a peculiar contradiction at the heart of the modern wellness movement. We have become extraordinarily attentive to the things we put into our bodies, yet remain remarkably indifferent to the materials we place against them. We scrutinise the ingredients in our food, question the purity of our drinking water, invest in sophisticated supplements, monitor our sleep and spend considerable amounts of money trying to understand the biological mechanisms that determine how well we age. We have become a generation fascinated by optimisation, increasingly conscious that longevity is not simply a matter of living longer, but of preserving the quality of the years we have. And yet, every morning, many of us pull on garments manufactured predominantly from petroleum-derived materials without giving them a second thought.

Consider the ritual. You wake up, put on a pair of polyester running shorts, pull a synthetic training top over your head, perhaps add a compression layer, and head out for a run or a morning session in the gym. You spend an hour exercising, your temperature rises, your skin becomes damp with perspiration and the fabric moves continuously against your body. Afterwards, you change, put the clothing into the washing machine and repeat the process a day or two later. It is an entirely ordinary routine, repeated by millions of people across the world, and one that has become so normalised that very few of us ever stop to consider the composition of the materials involved. We have been conditioned to judge our sportswear by how it performs, how it feels, how quickly it dries and whether it makes us look the part. Rarely do we ask what happens to the material itself as it is worn, washed, stretched and exposed to the human body over years of repeated use.

Having spent much of my life around sport, first as a competitive junior golfer and more recently through my return to tennis, alongside my interest in padel, fitness and performance, I have always appreciated the extraordinary engineering behind modern sportswear. I understand why the industry has gravitated towards lightweight, flexible and moisture-wicking materials. Anyone who has spent a summer afternoon on a tennis court understands the importance of clothing that allows the body to move freely and regulate temperature. But my growing interest in biohacking and longevity has gradually changed the questions I ask. I no longer look at a product exclusively through the lens of what it can do for me. I want to understand what it is made from, what has been introduced during its manufacture, how it interacts with the body and, perhaps most importantly, what we know about the consequences of prolonged exposure.

It was this curiosity that led me down a rather unexpected rabbit hole. What began as an investigation into the materials used in athletic clothing became an examination of the petrochemical foundations of the modern textile industry, the release of microscopic plastic fibres, the presence of potentially endocrine-active chemicals in consumer garments and emerging research identifying plastic particles in human reproductive tissues. The deeper I went, the more I began to question an industry that has become synonymous with health, fitness and athletic achievement. I am not suggesting that every synthetic garment is dangerous, nor that we should suddenly become fearful of the clothes hanging in our wardrobes. Science does not support such a simplistic conclusion. But there is a compelling case for asking whether the materials we wear every day deserve considerably more scrutiny than they currently receive.

And perhaps the most uncomfortable question of all is this: why has an industry dedicated to helping us become healthier spent so little time discussing the biological implications of the materials it puts against our skin?

THE PLASTIC REVOLUTION: HOW PETROLEUM BECAME THE FOUNDATION OF PERFORMANCE

To understand the problem, it is worth looking at how dramatically the clothing industry has changed over the last century. For much of human history, our garments were made from materials derived directly from the natural world: cotton, wool, linen, silk and hemp. These fibres were not necessarily perfect, and the limitations of natural materials were often considerable, but they were familiar biological materials that had been used by humans for thousands of years. The arrival of synthetic polymers transformed that relationship almost entirely. Polyester, nylon and elastane introduced manufacturers to a world of possibilities that natural fibres alone could not easily replicate. Suddenly, clothing could be engineered to stretch in several directions, resist abrasion, dry quickly, retain its shape and be manufactured at enormous scale for relatively little money.

Polyester, in particular, became the foundation of modern performance clothing. Most conventional polyester is made from polyethylene terephthalate, commonly known as PET, a synthetic polymer also used in the manufacture of many plastic drinks bottles and food containers. Through an industrial process, this material is transformed into extremely fine filaments that can be spun into yarn and knitted or woven into fabrics. Nylon, another petroleum-derived polymer, offers exceptional strength and abrasion resistance, while elastane provides the elasticity that has made modern compression clothing, fitted leggings and athletic shorts so ubiquitous. Together, these materials have allowed manufacturers to produce garments that are remarkably versatile, often at a fraction of the cost of high-quality natural alternatives.

There is, of course, a reason this revolution happened. The sportswear industry has been able to engineer clothing around the precise demands of athletic performance, and the benefits are genuine. A lightweight polyester running shirt can move moisture away from the skin more efficiently than a heavy cotton garment. Nylon can withstand repeated abrasion on a tennis court, while elastane allows clothing to move with the body without restricting movement. I would be the first to acknowledge the extraordinary engineering that has gone into these developments. The problem is not that synthetic materials have no value; it is that their performance characteristics have become so dominant that we have largely stopped questioning their wider implications. Somewhere along the way, the assumption that a fabric is good because it performs well has become almost indistinguishable from the assumption that it is good for us.

One of the most important discoveries in this area concerns the release of microfibres. Every time a synthetic garment is washed, worn or subjected to mechanical abrasion, tiny fragments of material can detach from the textile. Some are sufficiently large to be classified as microfibres, while others are considerably smaller particles. When those fibres are made from synthetic polymers, they contribute to the wider problem of microplastic pollution. They can enter wastewater systems, accumulate in household dust and become part of the environmental exposure that researchers are increasingly trying to understand. What makes this particularly relevant to sportswear is the frequency with which these garments are used and washed. A training top may be worn several times a week, washed repeatedly and subjected to considerable friction throughout its lifetime. The material does not remain entirely static simply because it looks unchanged to the naked eye.

A particularly revealing 2021 study examined the release of microfibres from different consumer textiles during domestic washing. The researchers found substantial variation between samples, with measured release ranging from approximately 9.6 milligrams to 1,240 milligrams per kilogram of textile per wash. Some mechanically treated polyester fabrics released approximately six times more fibres than the nylon samples examined, while the difference between the lowest - and highest - shedding textiles was approximately 850-fold. These findings are important because they demonstrate that the question is not simply whether a garment contains polyester. Its construction, yarn characteristics, surface treatment and manufacturing process can all influence how much material is released. Two garments that appear almost identical on a shop floor may behave very differently once they are subjected to repeated washing and wear.

Research published in Nature Water in 2024 added another dimension to this discussion by examining the particles released when polyester textiles are washed. The researchers identified oligomers as a major component of the submicrometre particles released, suggesting that the issue extends beyond the larger fibres that have traditionally attracted attention. Oligomers are smaller molecular structures associated with the manufacture and composition of polymers, and their presence adds complexity to the question of what exactly is being released from synthetic textiles. This does not mean that every particle released is absorbed by the human body, nor does it establish that wearing polyester causes disease. It does, however, demonstrate that the chemistry of textile pollution is considerably more complicated than the visible fibres that collect in a washing-machine filter.

I find myself returning to this point because it illustrates something fundamental about the way we think about modern materials. We have become very good at engineering substances to deliver a particular function, but considerably less comfortable discussing what happens to them throughout their entire lifecycle. We understand how to manufacture polyester to transport moisture away from the skin, but the same degree of public attention has not been given to the microscopic material released through repeated use. It is an imbalance that deserves correcting, particularly when the garments in question are marketed so heavily around health and physical performance.

THE SKIN IS NOT A LABORATORY BARRIER

There is another part of this investigation that I find particularly interesting, and it concerns the chemistry of the garments themselves. When we purchase a piece of sportswear, we tend to think about its primary material: polyester, nylon, cotton or wool. But the fibre composition is only one part of the story. Modern textiles can undergo an extraordinary number of additional treatments before reaching the consumer. They may be dyed, softened, made wrinkle-resistant, treated to repel water, given antimicrobial properties or coated to improve their durability. These processes can introduce additional chemical substances into the finished garment, and some of those substances deserve considerably more scrutiny than they currently receive.

Our skin is an extraordinary biological structure. It is responsible for regulating temperature, protecting us from pathogens, participating in immune defence and acting as a selective barrier between our internal environment and the outside world. But it is not impenetrable. Certain chemicals can migrate through the skin, with absorption influenced by molecular size, concentration, chemical structure, skin condition and the circumstances of exposure. This is particularly relevant when considering clothing worn during exercise. As our temperature rises and we perspire, the conditions in which fabrics sit against our skin change. Moisture, friction and prolonged contact may influence the migration of certain chemical substances, although the extent of that effect depends on the individual chemical and the garment involved. It would be scientifically irresponsible to suggest that every substance present in a textile is absorbed during exercise, but equally, it would be unreasonable to assume that the chemistry of clothing is irrelevant simply because it sits on the outside of our bodies.

One chemical that caught my attention during this investigation was bisphenol A, more commonly known as BPA. Most people will have encountered discussions about BPA in relation to plastic food containers and drinks bottles, but its significance extends much further. BPA is an industrial chemical that has been studied extensively because of its ability to interact with hormone signalling pathways. The endocrine system is responsible for regulating an enormous range of biological processes, from reproductive development and testosterone production to metabolism, thyroid function and the regulation of blood glucose. These systems operate through incredibly delicate signalling networks, and certain chemicals can interfere with the way hormones are produced, transported or recognised by cells.

A 2024 study published in Environmental Science and Pollution Research examined 57 textile samples and measured several bisphenols, including BPA, BPS, BPF and BPB. The researchers detected BPA concentrations ranging from below 0.050 to 625 nanograms per gram of textile, while BPS concentrations reached 2,474 nanograms per gram. They also modelled potential dermal exposure, including exposure from sweat-wet clothing. Their estimates for sweat-wet textiles frequently exceeded the European Food Safety Authority's tolerable daily intake benchmark for BPA. This is an interesting finding, particularly when considered alongside the conditions in which performance clothing is worn, but it needs to be interpreted carefully. The researchers' exposure estimates were modelled rather than direct measurements of hormone disruption in people wearing those garments. Exceeding a tolerable daily intake benchmark in an exposure model does not establish that an individual will experience a clinical health effect. Nevertheless, the identification of bisphenols in everyday clothing raises legitimate questions about textile chemical management and the information made available to consumers.

BPA is not the only chemical family worth understanding. PFAS, sometimes described as forever chemicals, have historically been used in certain textile treatments because of their resistance to water, grease and staining. They are particularly relevant to technical outdoor clothing, waterproof jackets and garments designed to repel moisture. Certain PFAS are extremely persistent in the environment and have been associated with a range of adverse health outcomes, including changes in cholesterol, immune effects and reproductive concerns. However, not every PFAS has the same properties, and the risk associated with a particular garment depends on the compounds involved, their concentration and the likelihood of exposure. Some high-molecular-weight PFAS polymers firmly bound to textiles are considered unlikely to be absorbed through the skin, while smaller residual compounds present a different question. The sensible response is not to assume that every waterproof jacket is dangerous, but to ask whether PFAS-based treatments are necessary and whether manufacturers can demonstrate that safer alternatives have been used.

Phthalates, certain azo dyes and formaldehyde-based finishing agents also form part of the wider conversation about textile chemistry. Some phthalates have demonstrated endocrine-disrupting properties, while certain aromatic amines released from particular azo dyes are recognised carcinogenic hazards. Formaldehyde-based resins have historically been used in wrinkle-resistant textile finishes, although their use is regulated and varies between products and markets. The important point is that a garment's biological and environmental profile cannot be understood simply by reading the percentage of polyester printed on its label. We need to understand the complete material and chemical composition, including the processes used to make the finished product.

I find it remarkable that consumers are now prepared to spend an hour researching the ingredients in a face cream but may purchase a garment intended to sit against their skin for hundreds of hours without asking a single question about its chemical treatment. Perhaps this is because clothing has always been regarded as something relatively passive, an external layer with little relevance to our internal biology. But as our understanding of environmental exposures develops, that assumption deserves to be reconsidered.

THE REPRODUCTIVE HEALTH QUESTION: WHAT ARE WE FINDING INSIDE THE HUMAN BODY?

Of all the areas explored during this investigation, the research into microplastics and human reproductive health is perhaps the most difficult to overlook. Reproductive biology is exceptionally complex, and the systems involved are influenced by a multitude of factors, including genetics, age, nutrition, metabolic health, environmental exposures and hormonal signalling. For years, conversations about fertility have tended to focus on familiar variables: sperm count, ovarian reserve, lifestyle, smoking, alcohol, stress and diet. Increasingly, however, researchers are investigating the possibility that environmental contaminants, including microplastics and chemicals associated with plastic production, may also be relevant to reproductive health.

For men, the testes are particularly interesting because they perform two essential functions: producing sperm and manufacturing testosterone. These processes depend on a highly specialised biological environment involving Leydig cells, Sertoli cells and the blood-testis barrier, which helps maintain the conditions necessary for normal sperm development. In May 2024, researchers published a study in Toxicological Sciences examining microplastic contamination in human and canine testicular tissue. The researchers identified microplastics in the human samples, demonstrating that plastic particles can be found within an organ central to male reproductive function. An earlier 2023 study published in Science of the Total Environment had also reported microplastics in human testicular tissue and semen. It examined six testicular samples and 30 semen samples, reporting an average of 11.60 particles per gram of testicular tissue and 0.23 particles per millilitre of semen.

I think it is important to pause over what these findings do and do not tell us. They demonstrate that plastic particles have been detected in human reproductive samples, which is scientifically significant in its own right. They do not demonstrate that the particles came from clothing, nor do they establish that their presence caused a reduction in testosterone or impaired fertility. We encounter microplastics through numerous routes, including food, drinking water, air and household dust. Identifying a particle in a tissue sample is also not the same as demonstrating that it has caused a biological injury.

Nevertheless, experimental research has begun investigating whether certain microplastics can contribute to oxidative stress, inflammation, mitochondrial dysfunction and changes in reproductive hormone signalling. Animal studies have reported alterations in sperm quality and reproductive parameters following exposure, although translating those findings into human risk assessments requires considerable care.

The female reproductive system presents an equally important area of investigation. In 2025, researchers published findings in Ecotoxicology and Environmental Safety reporting the detection of microplastics in human ovarian follicular fluid. The study examined 18 samples and identified particles in 14 of them. Follicular fluid is not an arbitrary biological compartment; it surrounds the developing egg within the ovarian follicle and provides a carefully regulated environment containing hormones, proteins and other substances involved in oocyte maturation. The presence of plastic particles in this environment raises questions about possible reproductive implications, although the small sample size and the technical challenges of measuring microplastics mean that the findings should be regarded as early evidence rather than definitive proof of harm.

Research into pregnancy has also identified microplastics in human placental tissue, with subsequent investigations exploring their presence in other maternal and foetal compartments. The placenta is one of the most extraordinary organs in the human body. It manages nutrient exchange, supports hormonal communication, participates in immune regulation and creates the biological environment in which a developing baby grows. The identification of plastic particles in placental samples has therefore attracted considerable scientific interest. Yet, once again, detection must not be confused with causation. Sampling contamination is a particularly important issue in microplastic research, and the methods used to identify and quantify particles are still evolving. We need larger, carefully controlled studies before drawing conclusions about clinical outcomes.

What makes these discoveries particularly relevant to the wider conversation about sportswear is not that they prove our clothing is damaging our reproductive health. They do not. Rather, they demonstrate that microplastics are no longer simply an environmental issue occurring somewhere beyond our front doors. Researchers are finding them in human biological samples, including tissues and fluids that are fundamental to reproduction. When considered alongside evidence that synthetic textiles release microscopic fibres and that certain textile chemicals can migrate under particular conditions, it seems entirely reasonable to investigate whether clothing contributes to our overall exposure burden. It is a hypothesis that needs testing, not a conclusion that should be presented as established fact.

I believe this distinction is essential. Good science should make us curious, not frightened. It should encourage us to ask better questions rather than leap towards the most dramatic interpretation of an emerging finding. But it should also make us uncomfortable enough to recognise where our knowledge is incomplete. The absence of definitive clinical evidence that polyester clothing causes infertility is not proof that every material and chemical treatment used in modern sportswear is harmless. There is a considerable difference between demonstrating that a particular exposure causes disease and establishing that an exposure deserves further investigation.

MERINO WOOL: THE NATURAL ALTERNATIVE THAT ISN'T ALWAYS AS NATURAL AS IT LOOKS

When consumers begin questioning synthetic sportswear, one of the first alternatives they encounter is merino wool. It is easy to understand why. Merino is a remarkable natural fibre, offering temperature regulation, moisture management and natural odour resistance. It can be comfortable across a surprisingly broad range of conditions, which makes it particularly attractive for base layers and athletic clothing. For someone trying to reduce reliance on conventional synthetic materials, it seems like an obvious solution. But there is an important detail about modern merino manufacturing that I think consumers should understand before assuming that every natural-fibre garment is entirely free from synthetic processing.

Wool has a naturally scaly surface. When exposed to heat, moisture and mechanical agitation, those scales can interlock, causing the fibre to felt and shrink. This is why untreated wool garments can be relatively difficult to machine wash. To overcome the problem, manufacturers may use shrink-resist processes, commonly described as superwash treatments. One established method is the chlorine-Hercosett process, in which the surface of the wool is modified before a polyamide-epichlorohydrin resin is applied. Put simply, a polymer-based treatment is used to help prevent the natural wool fibres from shrinking and felting during washing.

This is an important distinction for anyone specifically seeking to avoid synthetic materials. A garment can be predominantly natural wool while still having undergone a polymer-based surface treatment. However, it would be inaccurate to suggest that all merino wool contains a plastic coating, that most merino products necessarily use the same process or that treated merino has been demonstrated to shed more microplastics than polyester.

There are different shrink-resist technologies, different formulations and different manufacturing approaches, and the evidence comparing their shedding characteristics remains limited. A polymer treatment bonded to a natural wool fibre is also not automatically equivalent to a conventional polyester fibre.

What I would encourage consumers to do is ask more questions. Is the garment genuinely 100% merino wool? Has it been blended with nylon, polyamide or elastane? Has it undergone a superwash process, and if so, which one? Have antimicrobial or other functional finishes been added? These are reasonable questions for a manufacturer to answer, particularly when its products are being marketed towards people who are actively trying to reduce their exposure to synthetic materials. The lesson here is not to abandon merino. Quite the opposite. It is to appreciate that natural fibres can undergo extensive industrial processing before they reach our wardrobes, and that the word natural should never be treated as a substitute for transparency.

THE MATERIALS THAT COULD CHANGE THE FUTURE OF SPORTSWEAR

The encouraging part of this investigation is that we are not entirely dependent on conventional synthetic polymers. There are already materials offering interesting alternatives, although each comes with its own limitations and manufacturing considerations. Organic cotton, for example, remains a useful option for everyday training and lower-intensity exercise. It is a natural cellulose fibre, comfortable against the skin and relatively breathable, although its tendency to retain moisture makes it less suitable for garments designed for prolonged, high-intensity activity. Hemp and linen also offer interesting possibilities, with durability and breathability among their principal advantages, although neither is currently a straightforward replacement for elastane-rich compression garments.

Perhaps the most interesting developments are taking place in regenerated cellulose fibres, particularly TENCEL™ Lyocell and Modal. Both are manufactured from wood-derived cellulose and offer a soft, comfortable textile with useful moisture-management properties. Lyocell is especially interesting because its production process uses a solvent-recovery system designed to recover and reuse much of the processing solvent. This does not make the material environmentally impact-free, and the source of the wood pulp, energy requirements, chemical management and manufacturing standards all matter. But it does demonstrate that there are alternatives to building every performance garment around petroleum-derived fibres. Modal offers similarly interesting properties, particularly in clothing where softness and comfort are important.

There is still a considerable engineering challenge to overcome. The stretch, recovery and durability provided by elastane are difficult to replicate using conventional natural fibres alone. Anyone who has worn a well-designed pair of compression shorts or athletic leggings understands how important these properties are. The challenge for manufacturers is to develop alternative materials that can deliver comparable performance without simply introducing another synthetic polymer under a different name. I find this area of textile innovation particularly exciting because it creates an opportunity to reconsider what high-performance clothing should look like in the first place. Rather than accepting that plastic is an unavoidable requirement of athletic clothing, perhaps we should be investing in the research necessary to find better solutions.

THE BRAND THAT CAUGHT MY ATTENTION: BOLDWILL

Throughout this investigation, I have been particularly interested in companies that are attempting to approach sportswear from a different starting point. Among the brands we have explored, one that has caught my attention is Boldwill, founded by Erik de Groot. What I find interesting about the company's philosophy is that it challenges an assumption that has become deeply embedded in the industry: that performance clothing must necessarily rely on conventional synthetic materials. Its ambition is to explore how garments can be constructed using alternative fibres while retaining the practical qualities consumers expect from modern athletic clothing.

Boldwill uses materials including TENCEL™ Lyocell and Modal, both derived from wood-based cellulose, and has made material composition a central part of its approach. The company reports that more than 90% of its sewing thread is TENCEL™ Lyocell and that approximately 95% of its collection is plastic-free. These are company-reported figures, rather than independently verified comparative product findings, but they illustrate the direction in which the brand is attempting to move. Its remaining challenges are particularly interesting because they concern the very properties that make modern sportswear difficult to manufacture without synthetic components: stretch, elasticity and recovery. In garments such as leggings, elastane remains difficult to replace without compromising performance.

The company also describes using specially constructed yarns and approaches designed to limit the exposure of synthetic components to friction. Its published materials discuss testing for substances including PFAS, BPA and restricted azo dyes, alongside manufacturing and chemical-management frameworks such as GOTS, bluesign®, OEKO-TEX® and ZDHC. These standards cover different aspects of textile manufacturing and chemical management, and they should not be interpreted as a universal guarantee that a garment contains no potentially concerning substances. Nevertheless, I appreciate the fact that the brand is engaging with questions of material composition, chemical transparency and the practical challenges of moving away from conventional synthetic sportswear.

What I particularly respect is that the problem is not being presented as an easy one to solve. It is relatively straightforward to produce a cotton leisurewear collection and market it as a sustainable alternative. It is considerably more difficult to rethink the construction of clothing intended for people who exercise regularly and expect their garments to perform. After speaking to Erik and now having entirely switched to their PF42 shorts and PF19 tank top, it is clear for such a simple task the sheer amount of thought, care and attention that is required to create these products. I would rather see manufacturers acknowledge those challenges and invest in solving them than continue to rely on the assumption that synthetic materials are the only viable option. Boldwill is not the finished answer, and its claims deserve the same independent scrutiny as those of every other sportswear company. But its approach is precisely the sort of innovation I would like to see more of.

A DIFFERENT WAY OF THINKING ABOUT OUR WARDROBES

I have no intention of suggesting that everyone should throw away their existing sportswear or suddenly become anxious about every synthetic fibre in their wardrobe. That would be neither scientifically justified nor environmentally sensible. A garment that already exists and remains perfectly usable does not necessarily need to be discarded in favour of something new. In fact, extending the useful life of clothing can be a more responsible choice than constantly purchasing replacements. What I would encourage is a gradual change in the way we think about new purchases, particularly the garments we wear most frequently and those that spend the greatest amount of time in direct contact with our skin.

If I were rebuilding my own wardrobe today, I would start with the basics. Everyday T-shirts, underwear, base layers and clothing worn for lower-intensity exercise would be the first areas I would consider changing. I would look for well-made garments using organic cotton, Lyocell, Modal, hemp or appropriately processed merino wool, depending on the activity. For highly technical sportswear, where synthetic materials remain difficult to replace, I would become considerably more selective about what I buy. I would also start asking manufacturers whether their garments have been tested for relevant textile chemicals, whether they use PFAS-based water-repellent treatments and whether antimicrobial finishes are genuinely necessary. A recycled polyester label would no longer be enough to convince me that a garment represented a meaningful improvement in relation to plastic exposure.

There are also simple steps worth considering for people who already own a substantial amount of synthetic sportswear. Washing garments at lower temperatures where appropriate, avoiding unnecessary washing and reducing excessive mechanical abrasion can help limit fibre release. Laundry bags and washing-machine filtration systems specifically designed to capture microfibres may also reduce the number of fibres entering wastewater, although their effectiveness varies. These measures do not eliminate exposure, and washing is only one part of the picture, but they are practical ways of approaching the problem without creating unnecessary waste.

Ultimately, I think we need to become more discerning consumers. We should be less impressed by marketing language and more interested in the actual materials and processes behind a product. A garment described as sustainable, natural or healthy should be able to withstand a few questions about how it is made. The more consumers begin asking those questions, the greater the incentive for manufacturers to provide meaningful answers.

THE NEXT FRONTIER IN LONGEVITY MAY BE CLOSER TO HOME THAN WE THINK

There is something that has stayed with me throughout this investigation. We have reached a point where we are prepared to invest extraordinary amounts of time and money trying to optimise our health, yet we often overlook the everyday materials that form part of our immediate environment. We research the best supplements, compare recovery technologies, investigate the quality of our drinking water and scrutinise the ingredients in the products we apply to our faces. We understand that our health is influenced by a complicated interaction between genetics, lifestyle and environmental exposures. And yet, the clothing we wear for much of our waking lives is often purchased with little consideration beyond its appearance and performance.

Perhaps this is because clothing has traditionally been viewed as something passive. It is simply the layer between our bodies and the outside world, something we choose according to the weather, the occasion or the activity we intend to undertake. But the more we learn about the chemistry of modern textiles, the less comfortable that assumption becomes. Our garments are manufactured from materials that can release microscopic fibres. They can contain chemical treatments that migrate under certain conditions. And the wider scientific literature is increasingly documenting the presence of microplastics in human biological samples, including tissues associated with reproduction. None of these findings establishes that wearing polyester sportswear causes a particular disease, and it would be irresponsible to suggest otherwise. But they do provide a compelling reason to investigate the materials we wear with the same curiosity that we apply to the food we eat and the products we use.

I have always believed that the pursuit of longevity should be about more than simply extending the number of years we spend alive. It should be about preserving the ability to enjoy those years: to remain physically capable, mentally curious, active and healthy enough to participate in the things that make life worthwhile. Sport has been a constant part of that philosophy for me. Whether it is returning to the tennis court after years away, discovering the demands of padel or simply enjoying the physical and mental benefits of a challenging training session, movement is one of the things I value most. Which is precisely why I find this subject so important. If we are going to spend our lives investing in our physical health, it seems entirely reasonable to ask whether the materials we wear during those activities deserve the same level of consideration.

I do not believe we should approach this subject with fear. There are too many uncertainties in the science, too many variables in human exposure and too many gaps in our understanding to justify sweeping statements about the dangers of individual garments. But I do believe that we should approach it with a healthy degree of scepticism. We should question the assumption that performance and biological compatibility are automatically the same thing. We should demand greater transparency from manufacturers and encourage investment in alternative materials. Most importantly, we should recognise that the absence of definitive evidence of harm is not the same as definitive evidence of safety.

Perhaps the most interesting question is not whether we should stop wearing synthetic sportswear altogether. It is why we have accepted that plastic should be the default material for clothing designed to support a healthy lifestyle. Why should innovation stop at making a garment lighter, stretchier or quicker to dry? Why shouldn't the next generation of performance clothing also be designed with greater consideration for chemical transparency, material shedding and the biological environment in which it is worn?

We have spent decades engineering sportswear to make the human body perform better. I think it is time we started asking whether we can make it better for the human body, too.

Because the next frontier in performance may not be another supplement, another wearable device or another recovery technology. It may be something considerably more ordinary, something we have overlooked precisely because it has always been there.

The clothes we choose to put on every morning.

We have become obsessed with optimising what goes into our bodies. Perhaps it is time we paid equal attention to what we wrap around them.