What is the speed advantage of a wetsuit?

What is the speed advantage of a wetsuit?


Everyone knows wetsuits help keep you warm in cold water. Lesser known among the general public (but well-known among triathletes) is that wetsuits also make you swim faster! The buoyant neoprene in a wetsuit floats a swimmer higher in the water, decreasing drag and thus increasing swim speed.

But how much faster is a wetsuit? I’ve heard various rules of thumb: 10% speed increase; 4-6 seconds per 100m; 1 minute per kilometer. I’ve also heard various caveats: it depends on the swimmer’s skill (better swimmers benefit less); it depends on the swimmer’s body-type (naturally floaty people benefit less); it depends on the quality of the wetsuit (you get what you pay for); it depends on the fit of the wetsuit; and so forth.

So the answer is: It depends. Because I’m usually disinclined to let things go at “it depends,” I decided to conduct a field experiment. Reef & Run, which I’ve written about previously, provided the perfect laboratory. Almost every Thursday evening between June 21 and yesterday, August 23, I swam one mile in the ocean at East Beach in Santa Barbara. Two weeks were canceled because of shark sightings, and one week I was sick – leaving a sample of 7 swims.

The swim took place at the same time each Thursday: 6:30pm. The conditions were generally similar: low-mid 60s water temp; winds out of the W or SW, producing moderate surface chop and a W-to-E current (i.e., head current going out, tail current coming back). I would characterize them as “rough water conditions” – the view in the above photo is typical. The course was identical each week – a full mile (1609 meters) measured with GPS, and marked by permanently installed buoys.

Generally, I had done a full workout earlier in the day, plus one lap of the course as warm-up. So, for each of these races I was warmed-up but perhaps a touch fatigued. In any case – pretty close to an ideal setup for my field experiment.

My wetsuit is a cheap-o XTERRA Vortex sleeveless, which frankly doesn’t fit me very well. So – a conservative test of the wetsuit effect. Presumably, I would be even faster in a high-end, well-fitting, full-body wetsuit.

Me in the orange cap. Three-time Olympic water polo player Wolf Wigo at left. The two others in the photo were doing a different race. Photo by Mike Eliason, Santa Barbara News-Press

Of the seven races, I wore a wetsuit for four of them and went “naked” for three of them.

My wetsuit-assisted times were: 19:52*, 20:02, 20:14, and 20:14.

My “naked” times were: 21:36, 21:37, and 21:41.

* For the purpose of this analysis, I’m throwing out the 19:52 wetsuit-assisted time. That was the season opener, and it was different in several respects: gorgeous, flat conditions; bigger, more competitive field (thus more drafting opportunities). I’m not surprised I was substantially faster that week.

That leaves a sample of six times – three wetsuit-assisted and three “naked.” My average wetsuit time was 20:10, with a range of 12 seconds. My average “naked” time was 21:38, with a range of 5 seconds.

So, according to my field experiment, my personal “wetsuit effect” – even with an ill-fitting cheap-o sleeveless – was 1 minute, 28 seconds in an open-water mile. That converts to 5.5 seconds per 100m, or a speed effect of 7.3%.

Any other self-experimenters out there? Please leave your data in the comments!

17 Responses to “What is the speed advantage of a wetsuit?”

  1. John White

    2012-08-24T17:48:56+00:00

    Evan, thanks for taking the time to collect this data. I find it very convincing despite what might normally be called a small sample size ;-) Come on, you didn’t want to swim a few hundred miles for more validity?!? (kidding)

    Your times cluster well and show a clear repeatable gap. Pretty much perfect statistically. I haven’t ever done repeated mile swims like this, just 100yd repeats, but my experience and other triathlete/swimmer experience all supports your data.

    A 7.5% speed boost from equipment is enormous and can’t be ignored. This really supports your argument that results must be separated and/or swims held with distinct, sensible rules. To win a wetsuit-legal race, a swimmer must wear a wetsuit.

    Also, you’re pretty dang fast.

    Reply
    • Evan

      2012-08-24T22:25:01+00:00

      Thanks, John. My results were remarkably close to what I expected. Based on previous racing (in the same wetsuit) I had an intuitive sense that it made a difference of about a minute per 1K, and 90 seconds per mile. And like I said, my wetsuit’s not even a very good one.

      For what it’s worth (although I never did any testing) my sense is that the full-body textile “tech suits” formerly allowed in pool swimming made a difference of about 2 seconds/100. Maybe a little less than half the effect of a wetsuit – but still a substantial effect!

      Reply
  2. John Hughes

    2012-08-26T14:30:39+00:00

    Three years ago I swam 5 two-mile open water lake swims on the same course in fairly uniformly calm conditions. I swam two with the same sort of ‘farmer john’ suit, one with a Blue 70 rubber tri suit (designed for no-wetsuit triathlons) and my race jammers. I alternated the wetsuit and jammer races, with the Blue 70 race being in the middle. The two wetsuit race times were in the 40 minute range, the Blue 70 race was 42-something and the jammer times were 44-something. So, this is consistent with the wetsuit conferring substantial speed in freshwater OW swims.

    Reply
  3. Ken Classen

    2012-08-26T17:54:26+00:00

    John Hughes, If that was the swim series at Grant Ranch I remember that. I couldn’t touch ya in the wetsuit, I could draft you a while in the Blue 70 but you pulled away towards the end of two miles and in jammers we were are more typical neck and neck.

    Reply
  4. Colm

    2012-08-27T04:58:00+00:00

    One other effect I’ve noticed while swimming with wetsuited swimmers, is that wetsuits don’t give the same speed increase when swimming into chop/ wind. Probably because you’re a bit higher in the water and more susceptible to interference from the conditions? The corollorary is true too, when swimming with chop and prevailing wind, you get a little bit extra push when wearing a suit.

    Reply
    • Evan

      2012-08-27T10:30:21+00:00

      Interesting. I haven’t noticed that, but it does make a certain a amount of sense.

      Reply
  5. Bill

    2012-08-28T20:15:29+00:00

    Evan, Just came across your article. Interesting because I just completed a test with my new triathlon wetsuit (Orca Equipe) yesterday. Bought two weeks ago, and after competing last year in Triathlons without a wetsuit and finishing towards the back of the pack, decided to invest in a new suit.
    Here are my results and yes I was very surprised. Completed (2x 500m) swims at my local swim pool over 2 consecutive weeks(4 in total). Averaged 12min 30sec without suit and 10min 35sec with the suit on. Not tired after swim with suit.

    Reply
    • Evan

      2012-08-29T11:22:17+00:00

      That’s a huge effect! I’m glad I do a sport where you can buy your way to faster times.

      Reply
  6. Donal

    2012-08-29T05:36:55+00:00

    I’m reading this as:

    You wore a wetsuit.

    Reply
  7. Chicken O'Sea

    2012-08-29T08:25:45+00:00

    Its ok if you don’t inhale

    Reply
  8. To Freeze or Not To Freeze « Rambulatory Ambulatory

    2012-08-29T17:56:49+00:00

    [...] cold, I’ve never seriously considered wearing a wetsuit for an open water swim, even though you do go faster.  Part of the reason is because for some reason I still kind of feel like wearing a wetsuit is [...]

    Reply
  9. Ryan

    2013-06-25T01:10:18+00:00

    I’ll second your findings, they are what I concluded after testing wet suits a couple years ago. I’ve only every tested my wetsuit in the pool as I’ve deemed OW events to have to many variables – thought yours swims cluster incredibly closely together, particular since drafting was also in the mix.

    In the pool I tested a quality suit and a middle of the rangel suit (both full suits) and found very little difference between the two (however I didn’t text extensively). Over 4 1k TT’s each a week apart I went 13:57 (naked) 13:10 (Wetsuit (Quality), 14:11 (naked), 13:14 (wetsuit (Middle). The 13:57 was a PB at the time and I’ve always felt It was a standout swim when compared to the others. For that reason I tend to air on the side of the 14:11 time and concluded that its approx. 6 sec per 100m + (for triathletes) the benefit of being less fatigued after. Not exactly a huge sample size but it was enough data for me to swim away happily (hate wearing the suit in the pool so I was keen to not repeat it).

    I’ve surmised that there may be another 1-2 secs per 100 in it for OW swimming as the temperature of OW is far more conducive to swimming hard than overheating in a pool. I also feel that for triathletes that are not working maximally in the swim the benefit a wetsuit has is probably 1 sec greater than comparing maximal efforts with and without suit – but that’s just a thought. In theory I think wetsuits allow you to hold pace better and therefore more benefits over greater distances… but in reality the longer the distance between buoys in OW means more off course adventures so it probably negates itself. Maybe one day I’ll do a 4k TT in the pool with a wetsuit to compare to my naked ones but I’m not sold on trying this anytime soon.

    I read prior to this test in a published paper that wetsuits were worth 8 seconds per 100 for average swimmers, 5 for good swimmers and 2 for elite swimmers. I think their definition of average swimmer is probably better than what I’d call average but its still valid. Elite = Olympic.

    All of my findings, the article and your findings appear to confirm one another.

    Reply
    • Evan

      2013-06-25T11:44:49+00:00

      Ryan – very interesting analysis! Thanks for sharing. I think with both of our experiments there are some sample size issues… but food for thought nonetheless.

      Reply
  10. Rebecca

    2014-01-16T11:54:34+00:00

    Thanks for this. I know some people test wetsuits in the pool to see which suit is fastest for them. This article was helpful to me because I am thinking about doing a sprint tri, which has a “half mile” swim, which in my experience means anything from 500 yards to 1000 yards. Based on the tests people mention, I am thinking I will go without a wetsuit, seeing as I am very slow at getting my wetsuit off. If I gain 45 seconds by wearing it, but it takes 30-60 seconds to take it off, there’s not much benefit.

    Reply

Leave a Reply