Swimming to Antarctica_ Tales of a Long-Distance Swimmer - Lynne Cox [65]
Dr. Drinkwater told me, “You’re different. You have neutral buoyancy. That means your body density is exactly the same as seawater. Your proportion of fat to muscle is perfectly balanced so you don’t float or sink in the water; you’re at one with the water. We’ve never seen anything like this before.”
Her Zen-like finding meant that I didn’t have to use energy to either fight against sinking or pull myself down into the water to counteract buoyancy. This enabled me to swim more efficiently, and it helped me conserve energy—energy that I could use for propelling myself forward.
Researchers began observing my workout sessions along the Santa Barbara coast. In the early morning, just before sunrise, Dr. McCafferty, and sometimes his wife and their small dog, Sunshine, walked along the beach below the university dorms as I swam from Coal Oil Point to the pier and back. Before and after these workouts, I’d hide behind a bush and take my core temperature using a rectal thermometer, the only way to get an accurate reading after immersion in cold water. I always made a point of telling Dr. McCafferty my temperature just as joggers were passing; they’d give him quizzical looks, since it appeared to them that he was talking to the bushes.
Through the course of these observations, as well as countless others, Dr. McCafferty discovered that my body temperature before a workout was usually a degree below what was considered normal. By the end of a two-hour workout, after swimming in water between fifty and sixty-five degrees, my temperature had risen to a degree or two above normal. Dr. McCafferty explained that the human body has a natural thermostat that strives to keep its temperature at a set point. What my body did was to lower that set point so it didn’t have to work as hard to stay warm. This was all new and exciting information for the scientists and for me.
Dr. Drinkwater and Anne Loucks also made some interesting findings. They were thrilled when they discovered that I reacted completely differently than the average person when I swam in cold water. Most people who swim in fifty-degree water lose body heat more rapidly than they can create it, and so they go into hypothermia in a relatively short amount of time, depending on their conditioning, body fat, and many other factors. But the scientists discovered that I was different. After I’d been swimming for four hours in fifty-degree water, working out at a fast pace, Dr. Drinkwater and Anne Loucks measured my core temperature and found that it was up to 101 degrees. They hypothesized that I was working at such a high rate I was creating more heat than I was losing, I was able to reduce blood flow to my extremities efficiently, and my well-distributed body fat acted like an internal wet suit that kept me warm.
What I decided I needed to do was to swim in water temperatures that would simulate those in the Bering Strait or the Strait of Magellan. It was apparent that obtaining permission for the Bering Strait was not going to happen quickly, so I’d decided to shift my goals and set my sights on the Strait of Magellan. No one had ever attempted this swim. I thought it would be exciting and romantic to attempt a swim across a waterway where ships had difficulty navigating. It seemed like a big challenge, but I also thought that I could collect research information, core-temperature measurements and the like, that might be useful to the doctors.
I asked Dr. Drinkwater and Dr. McCafferty if it might be possible for me to swim in the cold-water research tank at the institute while they gradually lowered the water temperature over a two- to three-week period. Both Dr. Drinkwater and Dr. McCafferty were excited about the proposal, but when they approached the director