The "Film of Sweat" Was the Real Culprit! Mizuno Tackles the Challenge of "Superior Breathability When Wet"

Mizuno Corporation has developed "Dry Aeroflow," a groundbreaking new material that maintains exceptional breathability even when soaked with sweat. It's the result of a new approach to a fundamental problem that plagued conventional moisture-wicking apparel: performance loss caused by a "film of sweat."

So, why did a sports equipment company, not a raw materials manufacturer, dive so deep into material science to take on a challenge difficult enough to upend industry norms?

We talked to Kazuya Tajima from Mizuno, who led the development, to understand the philosophy behind using science to boost athlete performance and the story behind this technological breakthrough.

The "Film of Sweat": The Core Problem That Needed a Solution

Sweat is one of the biggest factors affecting an athlete's performance during intense exercise or in harsh summer conditions. While countless sportswear brands have boasted about their moisture-wicking and quick-drying features, the reality is that even the most breathable mesh loses its effectiveness once it's completely soaked. The development team at Mizuno decided to look beyond this accepted wisdom to find the real issue.

As a major sports brand working with athletes across a wide range of disciplines, Mizuno heard a universal complaint: the uncomfortable feeling of sweaty clothes clinging to the skin and trapping heat. Tajima zeroed in on this real-world feedback and the science of perspiration to pinpoint the root cause.

"No matter what apparel you're wearing, it gets soaked when you sweat. We heard time and again that in that state, even the most high-performance gear loses its functionality. So, we dug deep into what exactly is happening when fabric gets wet. We came to understand that the main culprit behind the discomfort and trapped heat was likely a 'film of sweat' that forms as perspiration clogs the fabric's pores," he explains.

Sweating is a vital physiological process for cooling the body. The heat of vaporization as sweat evaporates from the skin draws heat away from the body. However, when a "film of sweat" forms on the fabric surface, it blocks airflow and prevents that sweat from evaporating.

As a result, the body's temperature regulation system can't work properly, which triggers even more sweating and increases the risk of dehydration and a drop in performance. Mizuno concluded that this "film of sweat" was the fundamental problem they needed to solve. This marked the beginning of a challenge that would require them to rethink the very concept of moisture-wicking and quick-drying from the ground up.

Combining Opposing Functions in a Single Fabric: A Breakthrough Idea and Internal Hurdles

The solution the development team arrived at was to combine two inherently opposing properties—hydrophobicity (water-repellency) and hydrophilicity (water-absorption)—in a single piece of fabric. The idea was to place water-repellent material around the fabric's pores, which act as air channels, to prevent a "film of sweat" from forming. Meanwhile, dedicated water-absorbent sections would efficiently manage perspiration. They hypothesized that this structure would keep the air channels open even when the fabric was wet, thus maintaining breathability.

Materials combining water repellency and absorption are nothing new. Mizuno's goal, however, was to blend these properties with a sophisticated design philosophy, specifically to achieve the function of "preventing a film of sweat." But this unprecedented approach wasn't smooth sailing from the start. Tajima recalls the early days.

"It can be tough to get people to understand something completely new," he says. "But we had team members who were really passionate about the concept. We formed strong partnerships with them, and as we gradually brought the idea to life, a sense of 'this could be something incredible' started to spread throughout the company."

This challenge to defy convention involved not just technical hurdles, but also the obstacle of winning over the organization.

Hundreds of Prototypes and a Battle with Trade-offs: The 3-Year Quest for Perfect Balance

From the project's official start in 2016, it took about three years before "Dry Aeroflow" was released in 2019. During that time, the number of prototypes reached the triple digits—well over 100.

The biggest hurdle was finding the "perfect balance" to satisfy multiple functional requirements at once. Making the holes larger for better ventilation reduced strength and durability, while for a shirt, "sheerness" was also a key consideration. Functionality, durability, and the quality of the apparel existed in a complex trade-off.

"Durability and functionality often have a trade-off relationship, so finding the optimal balance to meet both requirements was the hardest part," says Tajima.

The development team meticulously tested countless parameters one by one: hole size and spacing, yarn type and thickness, knitting methods, and more. Through this painstaking process of trial and error, carefully identifying how each element affected functionality, the ideal balance finally began to emerge.

Exceptional Breathability Even When Wet: Data Reveals a Fabric That "Keeps Breathing"

The development team proved the fabric's innovative nature through a unique method: "measuring airflow resistance in a wet state." Standard breathability tests are conducted on dry materials, but Mizuno's goal was to maintain performance "after sweating."

When measured in a "wet state," a typical T-shirt material of similar thickness had an airflow resistance value of "60" or higher. In contrast, Dry Aeroflow registered a mere "approximately 0.1."

"This airflow resistance value shows how easily air can pass through—the lower the number, the higher the breathability," explains Tajima. "While the comparable fabric we tested had a value over 60, Dry Aeroflow came in at about 0.1. That just shows you the massive difference."

This figure was proof that the fabric continues to "breathe" and maintain airflow even when soaked with sweat. It was the moment that a feature directly linked to maintaining performance—not just a feeling of comfort—was validated by objective data.

A Never-Ending Evolution

Since its debut in 2019, the technology has continued to evolve. Initially designed for competitive sports, its application has expanded to lifestyle apparel and workwear for those in demanding environments. In recent years, most of these products have incorporated recycled materials. Spin-off models with enhanced cooling and quick-drying capabilities have also been developed.

Even after overcoming the major challenge of the "film of sweat," the development team's quest is far from over. "There's no project we feel we've ever 100% finished," says Tajima.

As environmental conditions become more demanding each year, the technology must also continue to evolve. The ultimate goal is to use the power of apparel to reduce physical strain to nearly zero, regardless of how an athlete moves. Dry Aeroflow is one realization of that vision, but it is also a milestone that represents Mizuno's endless evolution. The challenge is sure to continue.