In Japan, a wetsuit is compulsory for age group triathlon races, however warm the water. This weekend I have a notoriously hot Olympic distance race, Nagaragawa in Gifu. The water is expected to be 26C, but a few years ago it reached 30C. I am hoping that the 26C prediction is right. This leaves the choice of a full wetsuit or a sleeveless wetsuit. The full is faster, but it is warmer than the sleeveless. To find out how much faster and to get a sense of how much warmer, I tried out both wetsuits on an identical course at nearby Ohama Beach in Hayama.
As luck would have it, the water temperature was 26C, so this would give me a good idea about race day. The air temperature was 28C in the shade at 9 a.m. I started with the full wetsuit, as there is no way I would be able to get it on after I got wet. In contrast, the sleeveless wetsuit is quite easy to get on. Unfortunately, the GPS in the Garmin I am using is unreliable and tends to underread by 10 or 15%. Because of this, I simply plotted a course around the huge yellow buoys now marking out the areas where motor boats have to go dead slow.
Although the swim paths look a little different, I am pretty sure the distance was about the same as I simply used the rocks and buoys in the bay. I tried to swim at a steady, fast training pace, but if anything pushed a little harder when using the sleeveless. The temperature was noticeably more comfortable in the sleeveless which allowed me to push a little harder without overheating. In the full wetsuit, I reduced the pace a little as I started to feel uncomfortably warm. Despite this, the full wetsuit was much faster, and it felt that way. Here is the data:
Full Wetsuit
Time: 18:53
Strokes/min: 29
Sleeveless Wetsuit
Time: 20:09
Strokes/min: 29
I think the distance was about 1000 metres which means the full wetsuit is about 2 minutes faster over 1500 metres. I have done this simple test twice before and got similar results. In other words, if you can stand the heat in a full wetsuit, you can gain a couple of minutes in the swim. Alternatively, you can put in less effort for the same, slower time.
hayama3tri 