Jessica Antenico, who is working on a master’s in kinesiology at California State University in San Marcos, is participating in a wetsuit experiment there that studies heat loss.

Jon Cohen/Science

Scientists, surfers, and our own reporter team up to design a better wetsuit

One of the great joys of surfing is that when I enter the water, I’m off the grid. Yes, riding waves is a hoot, but I also love being out of touch with everything that’s not in my immediate surroundings. I even refuse to wear a watch. So there was something blasphemous early on the sunny morning of 1 November when I paddled out at a surf spot near my San Diego, California, home outfitted with eight miniature thermometers taped to my body as part of an unusual wetsuit experiment being run by a gaggle of undergraduate students on the bluff above me.

Like most serious surfers, I use the same wetsuit for about three winters, and it gets more wear and tear than any single article of clothing I own. But I don’t give any critical, scientific thought to how it works—or how it might be improved. Neither, it turns out, do most wetsuitmakers, who have favored trial and error over experiments. Which is why I let the students, who are taking a kinesiology class at nearby California State University in San Marcos (CSUSM), ruin my Zen.

Kinesiologist Sean Newcomer, who teaches the students’ introductory class in exercise physiology, has been gathering real-world data for the past several years about heat loss during surf sessions, and he’s working with a major wetsuit manufacturer, Hurley, to reduce it. “Lots of the surf industry is really resistant to getting any kind of scientific data,” says Newcomer, who, with his CSUSM colleague, kinesiologist Jeff Nessler, has published eight surf-related studies over the past 3 years.

The beginner’s surf spot where I met their students is named after Barney Rubble, the goofy best friend of Fred on The Flintstones; surfers have appropriated the name as a charming and even affectionate slang for newbies. Newcomer and Nessler rely on undergraduate Barney researchers to go to its parking lot and recruit surfers into studies there; they also conduct more controlled experiments in a flume—a pool that has a current—on campus. “We’re teaching STEM [science, technology, engineering, and math] through the use of action sports,” says Newcomer, who has surfed since he was a child and still is in the water by dawn on most days that have ridable waves. “Students are way more engaged than in the typical lab.” Of the 500 or so students who have come through their courses, 100 have later sought internships with him.

A diver wears one of Hugh Bradner’s first wetsuits (circa 1952).

Special Collections & Archives/UC San Diego Library

The wetsuit has a prestigious scientific heritage, though most research on the garment involves divers, long-distance swimmers, and other nonsurfers. One of its fathers (debates persist about who invented it) was Hugh Bradner, a University of California, Berkeley, physicist who worked on the Manhattan Project and after World War II wanted to improve on the drysuit used by the U.S. Navy’s underwater demolition teams. Drysuits keep out water and require a user to wear clothing underneath to retain heat, a getup that’s bulky and constricting. “If you’d ever used any of the so-called drysuits that the Navy had at that time, there’d be no question about the need for improvement,” Bradner said in a 1999 interview. Bradner in 1951 ran his idea for a wetsuit—a garment that is water-permeable but retains heat—by William Bascom, a legendary researcher and renaissance man at the Scripps Institution of Oceanography in San Diego, who suggested he try Rubatex, a flexible type of neoprene foam that’s still widely used as pipe insulation.

The next year, Bradner ran skin temperature measurements on Navy SEALs outfitted with his neoprene suit. “The military did cold water immersion studies, and that’s where lots of data about how to build wetsuits comes from,” Newcomer says. But surfers aren’t divers. “At no point in surfing are you intentionally sitting in water up to your neck.”

Indeed, when I surf, I walk into the ocean until the water hits my waist and I then jump on my board and lie prone, paddling out to the lineup, where the waves break. I might have to push through a few waves during my paddle, briefly submerging myself under whitewater, but I often make it to the lineup with dry hair. I then sit on my board and look toward the horizon for approaching swells. To ride a wave, I turn my board toward shore, lie down, and paddle. If I catch the wave, I pop up to my feet, and, if I don’t fall, I kick out at the end as I near the shore and then paddle back out. My hair might still be dry. Even if I do come unstuck from my board—a “wipeout” in ’60s lingo—I usually have a leash that attaches my ankle to it, so I’m only submerged for the few seconds it takes to surface, find my board, and jump back on it.

Head surf wetsuit researcher, kinesiologist Sean Newcomer

Jon Cohen/Science

Newcomer and his collaborators put a finer point on this in the April 2017 issue of the Journal of Aging and Physical Activity, as part of their research paper detailing cardiovascular responses during surfing. Citing the few studies that do exist, they note that the time spent “surfing” consists mostly of paddling (44%–58%), followed by sitting on a board or lying stationary (28%–42%), diving under waves or swimming (2%–16%), and then riding waves (4%–8%). In May, the group published a study in Ergonomics that it claimed was the first to ever show that this “dynamic nature of surfing” means “significant differences in skin temperature profile exist across the body” while wearing a wetsuit. “We’re fascinated that they’re doing surf-specific research,” says Bruce Moore, vice president of innovation at Hurley in Costa Mesa, California. “That’s definitely led us to make changes in design.”

There’s a “duh” aspect to many of the group’s findings, but their implications largely have escaped the attention of wetsuitmakers until now. “There’s a history in our sport of fuzzy math and claims and marketing and not a lot of accountability,” says Evan Slater, who made his name in the surfing world riding the massive waves dubbed XXL and now works as Hurley’s senior director of brand communication. “Nobody’s really checking up on it.” (Hurley helps fund Newcomer’s studies.)

Undergraduates meet at Barney’s with their professor to recruit surfers into their wetsuit study.

Jon Cohen/Science

My winter wetsuit (full disclosure: not a Hurley) covers my entire body except for my feet, hands, and head. It has 3-millimeter neoprene on the torso and 2 millimeters elsewhere, a thickness that works well in southern California winters, where the water temperature rarely drops below 13°C. The popular 3/2 design idea is that, as one manufacturer boasts, your wetsuit offers you “insane flexibility” without sacrificing “ultimate warmth,” whatever that is. Newcomer says his team of field researchers has “a good grasp” of where heat loss occurs. As the Ergonomics study in 46 surfers shows, during a 1-hour surf session, skin temperature declines the most in the calf and thigh—which are in the water more than any body part—then in the lower abdomen, forearm, and lower back. It changes least in the upper parts of the chest, back, and arm. In other words, the body areas that lose the most heat are the least protected by standard wetsuit designs, Newcomer says.

The basic physics is that body parts lose more heat when they’re submerged because the thermal conductivity of water is 25 times greater than that of air. Research has shown this leads to up to five times greater convective heat loss. To that end, Newcomer’s team now wants to understand how to retain that heat most effectively.

Thermistors track heat loss during a surf session with an experimental wetsuit.

Jon Cohen/Science

For my stint as a surfing guinea pig, the CSUSM students gave me a special wetsuit made by Hurley for their study. They taped thermistors—thermometers the size of the disc batteries used in watches—on my chest, back, and arms to record changes in my body temperature every minute during my surf session. “One of the things the wetsuit industry perceives is that the different types of neoprene have different insulation thermal capacity,” explained Newcomer, pointing out that the two panels that form the chest on my test suit were each made from different material. “And this is all driven by anecdote.” A Velcro-fastened belt strapped over the wetsuit on only one wrist will allow his group to compare heat retention through that favorite water entry point.

We’re fascinated that they’re doing surf-specific research. That’s definitely led us to make changes in design.

Bruce Moore, Hurley

The sophisticated attempt to examine these questions is set against decades of ridiculous wetsuit ads. When I was 14, O’Neill Wetsuits, one of the largest in the surf industry (started by another inventor), infamously ran an ad that led my high school library to pull Surfer magazine from the racks: It showed a bare-breasted woman zipping up the front of her suit with the preposterous selling point, “It’s always summer on the inside.” Dive n’ Surf, the wetsuit shop near my high school home, named their product Body Glove, because that’s how it fit, and the company offered a “Cossack model”—go figure—that was “outtasight!” I’ll stop there.

Surfing wetsuits have vastly improved since my first one, which was a two-piece, stiff, modified diving suit. But today’s ads remain filled with mumbo-jumbo and pseudo-science that aims to take advantage of the fact that the only scientist many surfers can name is Albert Einstein (who did design a refrigerator). The O’Neill Psycho Freak model, for but one example, is “psychotically warm” because of its “exclusive Technobutter 3, maximum strength, hydrophobic neoprene with featherline ENVY foam rubber core.”

Science’s Jon Cohen (center) as he joins the experiment moments before a surf session

Jon Cohen/Science

For proprietary reasons, Hurley won’t say how its 2019 suit incorporates the new data, and Moore says they’re looking forward to future studies. “Wetsuits can always get lighter, warmer, and more flexible,” he says, noting the company is interested in testing materials other than the tried-and-true neoprene. “Ultimately, we’re trying to create a second skin.” (Patagonia has already moved to more environmentally friendly material for its surfing wetsuits, a latex extracted from hevea trees called Yulex.)

Jeremy Sheppard, who has a Ph.D. in sports science and has widely published studies about training for surfing, says he’s “really encouraged” by the CSUSM-Hurley collaboration and imagines they can design wetsuits that actually improve the way people surf. “In other sports apparel, your wear enhances your performance,” says Sheppard, a trainer with Canada Snowboard in Whistler. “Shouldn’t we get to the place where wetsuits are reducing injuries or making you paddle faster?”

Newcomer envisions a day when surfers will match their wetsuits to the volume and length of their boards, which affects how much contact the body has with the water. He also hopes his surf studies, which extend far beyond wetsuits, will up the game of competitive surfers—who will be in the Olympics for the first time in 2020. “Traditional sports—baseball, basketball, football, soccer—were all informed by scientific inquiry, both to enhance the performance of athletes and product design,” he says. “If all the other sports are doing this, why not surfing?”

*Correction, 3 December, 11 a.m.: This story originally said the thermal conductivity of water is 25% greater, not 25 times greater, than that of air.