Mother Nature Has A Locke On Joe

Mother Nature Has A Locke On Joe

Joe Locke voluntarily and wisely pulled out after meeting Mother Nature last night. With ice on the docks and snow lining the banks of Lake Tahoe, Joe may have bitten off a bit more than was physically possible when he set off on his double-crossing attempt. Paul Lundgren summarized after Joe stopped three miles from the completion of his first leg, “It got really cold and kept dropping. When it dropped below 55°F (13°C) and the air was below 32°F (0°C), he got really cold. 50°F (10°C) in San Francisco Bay isn’t as cold as 55°F here in Lake Tahoe. He knew his limitations. He simply stopped when he got hypothermia, but he recovered in 30 minutes.”

There are some sensations that open water swimmers know about the differences in how the water feels in a lake vs. an ocean vs. a pool and at altitude.

The water temperature in a lake, ocean and pool of the same temperature all feel different. A 2°F (1.8°C) difference seems to exist between lake and ocean waters, so 64°F (17.7°C) in the ocean feels similar to 66°F (18.8°C) in a lake. Karen Reeder, an experienced marathon swimmer explained. “I have experienced also that pools have even a colder ‘feel’ than lakes do. If it is about the same difference as lake/ocean and applied to the chart, it would make sense to pool coaches as well.”

78°F (25.5°C) ocean = 80°F (26.6°C) lake = 82°F (27.7°C) pool
80°F (26.6°C) ocean = 82°F (27.7°C) lake = 84°F (28.8°C) pool
82°F (27.7°C) ocean = 84°F (28.8°C) lake = 86°F (30°C) pool

But then these sensations seem to be even greater when swimming at altitude. That is, swimming at altitude makes the water seem colder. The physiological mechanism for these differences have not been widely discussed among the open water swimming community. But physicist and South End Rowing Club member Paul Springer once explained about the difference in feeling in salt water vs. fresh, “Pure water has a higher heat capacity than sea water (4.20 vs 3.99 KJ/Kg degree K) because of its rotational and vibrational degrees of freedom. So when your body gives off heat – salt water near you gets warmer than fresh water – keeping you warmer too.”

Copyright © 2011 by Open Water Source
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