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When most people think of a university laboratory, they imagine white coats and beakers, or perhaps robots and lasers. Rarely do they envision a giant pool and researchers clad in wetsuits. Yet at Spain’s University of Granada Aquatics Laboratory, that’s exactly what takes place. In this academic setting, researchers like Ana Gay Párraga dive into age-old questions like “How much faster does a wetsuit make you swim?”

It might seem like we’ve answered this long ago. After all, just about every triathlete will tell you definitively that wetsuits make you faster. They’ve experienced it in their own races, and they can tell you they swam X seconds faster at Ironman Chattanooga than they did at Ironman Arizona. Wetsuit brands can make claims that their product shaves Y minutes off an Ironman swim time. But anecdotal evidence is not fact, and brand-sponsored studies are usually biased, skewed, or massaged into something more impressive than it actually is (a fact that is often glossed over in advertising). To absolutely ascertain just how much faster a wetsuit can make the athlete wearing it, a certain degree of scientific rigor is required.

“There are opinions and beliefs about the effects of wetsuit use on swimming and triathlon performance, but it is important to show the scientific evidence about it,” Párraga says. The researcher has vested personal interest – as a triathlete and coach, she often uses wetsuits herself – as well as a professional one that relates to her PhD study of sports sciences at the University of Granada.

The answer to a simple question like “How much faster does a wetsuit make you swim?” isn’t simple at all: Párraga and her team compiled – and in some cases, conducted – 26 smaller studies on wetsuit use and swimsuit use over different distances, measuring devices, and environments (swimming pools versus open water). The result of all of those individual elements – things like physiology or biomechanics – all came together in a 2022 report in the journal Physiologia to create a big-picture view of how a wetsuit affects swim performance when compared to wearing a swimsuit only.

RELATED: The Evolution of the Triathlon Wetsuit

Although the swimming wetsuit was originally designed to prevent hypothermia in open-water events, users also felt they swam faster and better. This improvement has traditionally been credited to the buoyancy generated by the neoprene textile, which allows for a flatter and higher horizontal position in the water when swimming.

“Hydrodynamic drag is reduced,” Párraga explains the way the neoprene affects swimmers—particularly those with a poor natural position. “Therefore, the swimming efficiency improves and the energy cost is reduced. This results in an increase in swimming velocity.”

But how does that translate to speed? In one study conducted by Párraga at the Aquatics Lab, swimmers were tested in wetsuits and swimsuits only during a 400-meter freestyle test in a swimming flume (a small, counter-current pool such as an Endless Pool) and in a 25-meter swimming pool. The results were then compared to past smaller studies on swimming speed, an important part of the scientific validation process known as replication.

“We have been able to corroborate how swimmers increase their swimming speed by 0.07m/s with a wetsuit compared to a conventional swimsuit, resulting in a 6% improvement, or 20.08 seconds, on 400m [freestyle swim] performance,” Párraga says.

Additionally, Párraga’s research team crunched the numbers on wetsuit use in distances from 25 meters to 1,500 meters. “Wetsuit use, both full-body-and sleeveless, improves performance by 3.7% compared to a swimsuit in the longer distance studied [1,500 meters],” Párraga says. “So the wetsuit improves performance, as the literature shows, but it will depend on the distance.”

Párraga also cautions that swimmers and triathletes shouldn’t be so quick to assume a wetsuit is a miracle fix with the same amount of improvement for everyone: “We have to keep in mind that every study included in this review reports data of triathletes and swimmers with different swimming levels, years of experience, and age. So we should read it carefully when interpreting the results.”

For as long as wetsuits have been a part of the sport, many triathletes have assumed a full-sleeve wetsuit is better. After all, more neoprene means more flotation and protection from the cold – surely, that translates to a faster swim, right?

Not necessarily, says Párraga. “In our study, it was observed that the more experienced swimmers will reach better performance when using a sleeveless wetsuit compared to a full-body wetsuit.

When assessing regional-level swimmers and national-level triathletes, swimming speed in a full-sleeve wetsuit improved by 7.1 and 11.3% over swimsuit-only splits, respectively; stroke length improved by 6.4 and 8.4%. But when using a sleeveless wetsuit, swimming speed increased by 11.8%.

RELATED: The Best Sleeveless Wetsuits for Triathlon

Párraga says this may be explained via limitation of movement within the shoulder joint while wearing a full-sleeved wetsuit, which can be restrictive and modify both stroke rate and length. This is even more pronounced in less-experienced swimmers and those with more muscle mass to fit inside the sleeves.

Though buoyancy matters – the more the body is covered by neoprene, the more you’ll float – comfort and technique matter more. Deciding on sleeved versus sleeveless wetsuits, then, may come down to how much you can practice in the suit to get used to how it affects your swim stroke.

RELATED: Ask a Gear Guru: Should I Wear a Sleeved or Sleeveless Wetsuit?

When it comes to wetsuits, is it better to spend more money to get more speed?

“This is a key question when choosing a wetsuit,” Párraga says. “To answer it requires understanding how a wetsuit works.”

To insulate the user from cold water, a wetsuit is composed of neoprene textiles with small gas bubbles encapsulated in synthetic rubber. This produces thermal insulation due to a reduction in convective heat loss. In other words, the little bits of air between you and the icy depths retains warmth and protects you. Think: That koozie that protects your hand from your favorite cold beverage.

But not all neoprene is created equal. Thinner, more flexible neoprene allows for less constriction and better movement, but it’s also more expensive (and delicate) than its thicker, less-flexible counterparts. Less constriction and better movement can sometimes translate to less fatigue and more range of motion to better replicate the non-wetsuit stroke you’ve so carefully crafted in the pool over thousands of laps.

Most wetsuits are not entirely neoprene; some wetsuits also contain single jersey-knitted fabrics or textile fabrics, which have their roots in other sports such as diving or surfing. These wetsuits are also designed to avoid hypothermia but, in some cases, also to either save money, to increase durability, and/or increase warmth. As a result, the quantity of neoprene rubber is lower and the ratio of textiles is higher, creating a lower buoyancy and thus lower or even zero improvement in swimming performance. In other words, while a surf or dive suit might keep you warm and save you from a dangerously chilly swim, it’s unlikely either will make you faster. Probably just the opposite. RELATED:Can I Wear a Surf Wetsuit for Triathlon?

“For training and competition, I would opt for a wetsuit composed of neoprene rubber for the most part, avoiding textile parts if possible,” Párraga advises. “The neoprene rubber not only will improve performance due to the buoyancy provided but also it will prevent hypothermia.”

But even the most expensive wetsuit in the world won’t make you faster if it doesn’t fit. When it comes to buying a wetsuit, contour to your unique shape matters a lot in reducing hydrodynamic drag.

“It’s important to select a suit which fits perfectly to the body, avoiding wrinkles and baggy parts around the hip, shoulders and knee joints,” Párraga says. “It will prevent a huge amount of water passing through the wetsuit, nullifying the thermal properties and at the same time, worsening your performance – you’ll swim carrying a mass of water that is between your body and the wetsuit.”

In short, the question is not whether a more expensive wetsuit will make you faster – it’s which wetsuit fits you and your needs as a triathlete.

RELATED: What Matters (and What Doesn’t) When Buying a Wetsuit

Triathletes like to obsess over the bottom line: How much faster will this wetsuit make me? But in hyperfocusing on one thing, they may forget others. For one, a wetsuit only makes you faster on race day if you’re used to wearing it.

“A determinant factor in benefiting from the wetsuit use is adapting to swimming with it,” says Párraga. “As reported in our study, wetsuit use changes swimming technique, modifying stroke rate and length compared to swimming with a swimsuit.”

There’s also what happens after the swim is over. Saving 30 seconds on the swim leg can quickly be negated if you’re struggling for minutes to take off your wetsuit in T1. “Practicing transitions, especially removing your wetsuit quickly, is important. You can be perfectly adapted to your wetsuit while swimming, if you don’t remove it quickly, performance improvements in the water will be in vain. The shorter the competition distance, the shorter the performance improvements, and the more important transitions become.”

RELATED: Your Step-By-Step Guide to Triathlon Transitions

To corroborate if your wetsuit improves your performance, Párraga encourages triathletes to conduct their own study of one. To perform a test, choose a swimming pool or open-water environment for a time trial while wearing a swimsuit (or trisuit) on the first day, and then a wetsuit the second.

“To do it correctly, remember to perform the same distances and conditions in both trials,” Párraga says. “Leave at least one day of rest between the two tests.”

Remember to hydrate well, especially if you’re testing a wetsuit in an indoor pool, where temperatures can hover between 75 and 80 degrees Fahrenheit. Overheating in the pool test swim can also skew results if you’ll be racing in chilly water with your wetsuit.

And don’t forget to time yourself taking off the wetsuit, says Párraga: “You will probably spend more time removing your wetsuit after the swimming is done. Transitions should be part of your daily training.”

RELATED: The Best Triathlon Wetsuits

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