We really tested the limits yesterday, but everyone was able to manage the extreme temperatures without any complications. Just a few notes:
– Cold water priming (progressive cold shower) 45 minutes prior to immersion makes a huge difference at these temperature ranges.
– Hot water poured into the neoprene gloves prior to the swim goes a long way towards keeping your fingertips from getting numb while in the water. It’s also effective at the end of the swim. Just pour some hot water (or hot tea in my case) into your gloves while you’re still wearing them and they’ll hasten your recovery time.
– It is essential to get a solid night’s sleep the evening prior to such a swim. In my personal experience, anything less than 7 hours of sleep begins to compromise your body’s ability to effectively thermoregulate. While this is no big deal in more moderate temperature situations, this can make or break you when you’re venturing into the more extreme ranges.
– Proper insulation of the head and neck is critical. I opted to wear my divers hood untucked this time around which for me was a mistake. The design of my hood must not be as snug as everyone else’s hoods, so I felt a searing “piano wire” sensation on my neck when I fully submerged myself. This, I am sure, triggered the sudden elevated heart rate and shallow respiration responses (next time I’ll tuck it in!).
– Dehydration is a real danger in this activity and can easily accelerate hypothermia. Drink lots of fluids the day before and lay off the caffeine if you can. Also, watch your electrolyte levels and take an electrolyte supplement that morning or the evening before.