In triathlon, most deaths occur during the swim leg, and more insight into risk factors, such as hypothermia, is warranted.  One subject with a low body mass index and a long swim time experienced hypothermia (<35 °C).  To conclude, the present study indicates that during the swim leg of a full-distance triathlon in water temperatures ≈ 15-16 °C, subjects with a low body mass index and long swim times may be at risk of hypothermia even when wearing wetsuits.
THERM