Cold water preparation: nature or nurture?

t’s cold outside. The water is also cold – freezing cold in many locations. Throughout the winter months, there are a large and growing number of Polar Bear Swims around the world. The swims range from Hawaii (Maui Polar Bear Fin Swim) to Finland (Finnish Winter Swimming Championships).

What is the best way to prepare for these cold-water swims? It reminds us of the nature vs. nurture debate. Modifying this classic debate for our sport, is an open water swimmer’s innate qualities (e.g., body fat percentage, natural ability to withstand cold water, mental toughness, ability to push oneself) more important than the swimmer’s personal experiences (e.g., amount of training and acclimatization to cold water) when determining one’s ability to swim well in cold water?

 One 25-year-old former pool swimmer of slender build (170 cm, 54.4 kg or 5'-7", 120 lbs.), Laurin Weisenthal, is one example that nurture certainly plays a very important role in cold-water swimming performance.

The background of this nature vs. nurture debate is the Dolphin Club's annual Polar Bear Challenge in San Francisco. The competitors attempt to swim 64K (40 miles) between December 21st to March 21st when the air ranges between 4° and 10°C (40° - 50°F) and the water is between 8.3°-10.6°C (47° - 51°F).

Records for the Polar Bear Challenge include (1) the shortest number of days to 40 miles, (2) the shortest total elapsed time to complete 40 miles (including rest and re-warming periods), and (3) the total number of miles completed. The swims take place in Aquatic Park, a protected cove influenced by tidal currents.

The total elapsed time competitions are unique in that they subject the swimmer to multiple repetitive periods of hypothermia and re-warming throughout the course of several days. In laboratory rats, repetitive cold water swim stress, with intermittent re-warming periods, produced what psychologists call 'learned helplessness' and 'behavioral despair'.

The repetitive chilling and re-warming cycles produce unique psychological challenges beyond the obvious physical challenges. Many (if not most) people in our open water swimming community who do cold water swims agree they are quite happy to warm up and they do not relish the thought of quickly re-entering the water for another cold-water swim on the same day.

The existing record for the "Fastest 40" was set by Daniel Considine in March 2008. Daniel completed the 64K Polar Bear Challenge in 3 days, 12 hours and 43 minutes (84 hours and 43 minutes).

Daniel's record was broken in the last week of 2008 by Laurin who completed 65K (40.5 miles) in a total time of 2 days, 12 hours (60 hours flat). Laurin swam 14.5 miles (23.3K) in five segments in 11 hours in 10.3°C (50.6°F) water on Day 1, 11.5 miles (18.5K) in five segments in 10 hours in 10.0°C (50°F) on Day 2, and 14.5 miles (23.3K) in six segments in 12 hours in 9.8°C (49.6°F) water on Day 3.

Laurin, who was coached and escorted by veteran Reuben Hechanova, explained her preparation, "I had been swimming in Aquatic Park since September, about 2.5-3 miles 2 or 3 times a week. The Sunday before the Polar Bear Challenge started, I wanted to see how my body would react, so I did 3 x 2-mile swims in 52°F (11°C) water in Aquatic Park, resting and re-warming similar to what I was going to do during the actual Challenge. After that, I decided it wasn't so bad, so I figured I'd just go for it!"

Laurin emerged from San Francisco Bay after each swim segment with moderate to severe subjective hypothermia according to her father who is a physician. Her re-warming routine consisted of 20 minutes in a shower (cold, then warm, then hot) while she consumed a portion of a baked potato, warmed Clif Bar electrolyte drinks, and 100 calorie GU energy gels. She then spent 20 minutes in a sauna. Dressed in boots, a swim parka, and a ski cap, she then rested for an additional 20 to 40 minutes at room temperature before preparing for the next water entry and swim.

Video clips of Laurin’s swims are here.

So it is nature or nurture? A combination perhaps?