The blood shift from the extremities to the core to protect valuable organs against the cold and increased water pressure is a boon to freedivers. Unfortunately, it spells disaster for our hands and feet, especially if both feet have been crammed into the footpocket of a standard monofin.
Monofin freedivers, myself included, have suffered from foot problems due to cold and constricted blood circulation. While no one has had any toes amputated (yet), the lack of blood flow has caused tendonitis, numbness, prolonged under-circulation, and even aches and strange sensations days later.
Save your feet! Get out before they turn numb and promote circulation by moving around, swinging your legs at the hip to drive blood downward, massaging toes, and stamping your feet gently on the ground. Swimming with numb feet can injure or damage nerves, tendons, and tissues, never mind the risk of frost nip or frost bite. Feet can be warmed with lukewarm water. Another method to warm the feet is to swim vigorously and then suddenly get out of the water and remove your fins or monofin, and sit down, keeping your feet off any cold ground. Blood will now rush to the feet and warm them up.
Putting It All Together
To maximize the body’s potential to generate heat, use the following strategies:
- Eat lots of good fat and protein in the days leading up to diving. Load carbohydrates the night before for optimal glycogen storage. Snack while diving. Drink water.
- Avoid fasting! Eat at least 2-3 hours before diving.
- Surface swim between dive sessions. For example, make ten dives, then go for a swim, snack, increase circulation in your feet and hands, then back to diving.
- Reheat extremities frequently. Poor motor control in your hands and feet can be a safety liability in an emergency.
- Get out or warm up when you start intense shivering.
PART TWO: CONSERVING HEAT AND PREVENTING HYPOTHERMIA
Now that we have a better idea of how to generate the most internal heat for winter freediving, the next challenge is to conserve that precious amount for as long as possible.
Let’s list the best ways to lose heat in a freediving situation:
- while getting changed outside
- direct exposure to cold water
- inadequate insulation
- breathing in cold air
- shivering, vasodilation, cold extremities
It is a shame that many freediving novices try the sport and eventually quit. Often they are given a badly fitted surfing wetsuit with a separate hood or a bulky, restricting scuba semi-dry suit. A freediving suit should be snug like blubber on a Beluga! Even if you buy a high quality freediving suit, without nylon, getting it custom fit can eliminate the occasional trickles of cold water on your lower back or down your neck. A custom-fit suit is a simple thing, yet it is surprising how few actually try it.
Wearing an extra layer works best with Yamamoto neoprene. The added flexibility of wearing neoprene without nylon allows you to wear an extra layer in relative comfort. The greatest advantage is the thicker neoprene around the head. No more ice cream headaches! Given the high blood circulation to the head and brain, this area has a great potential for heat loss.
Above all, try to stay warm while getting dressed. Too many people waste time and get cold even before they change into their suits. I have an unpleasant memory of shivering as I stepped into the water on my first ever November dive. If I remember correctly, I lasted about half an hour. Now, on most days, it takes an hour or more before I feel the first twinges of a tremor.
In the morning, put on multiple layers of clothing and natural fibers like wool that insulate even when wet and a windbreaker with a hood. Keep moving and don’t linger on shore. You should be extremely hot by the time you are ready to put on your wetsuit. You should crave the cold water to feel refreshed. However, you should avoid sweating and the extreme vasodilation that accompanies it.
Some Winter Diving Tricks
- Change on plastic mats and towels to insulate your feet from the cold ground, concrete or snow
- Store your suits inside your car, not in the trunk (so your body doesn’t have to warm them up)
- Use lukewarm water in small amounts to return circulation to hands and feet after diving
- Use duct tape around ankles
- Breathe through your snorkel to pre-warm the air before it enters your lungs
- Use a mask with a larger skirt to protect your face
- Try sodium-acetate heat packs between two layers of neoprene or in a nylon pouch (otherwise you can burn you skin)
- Have a hot thermos of drinking water
- Use an extra rubber weight belt around your hips to prevent water exchange
PART THREE: WINTER SAFETY
It goes without saying that all the usual freediving safety precautions apply in winter diving. There are also some added risks to address:
- Tell someone your dive plan, especially if it involves long surface swims, night diving or a boat dive
- Check weather and plan for the worst
- Dive in groups of three or more whenever possible (one to rescue, one to go for help)
- Always dry bag your clothes
- Bring hot drinking water and extra food.
- Bring a cell phone for emergencies (make sure it works at the dive site)
- Check your neutral buoyancy point and modify your weight belt and remember that with more weight you will be heavier at negative buoyancy
- Know the early warning signs of hypothermia and what to do (take an aquatic first aid and CPR course)
- Be aware that decreased core temperature can potentially worsen narcosis at depth
PART FOUR: ESOTERIC ALTERNATIVES
There is another way…
Although science may give us many clues on how to stay warm in the cold, certain people choose a more ancient method: the method of the Tibetan Buddhist yogis.
The Tibetan Buddhist yogis are famous for a practice they call, ‘achieving through spiritual flame.’ Students of the spiritual flame may practice the technique for months or years in a monastery, but they must eventually pass the real test out in the freezing snow. Prospective graduate students are made to meditate on freezing snow (often in snow storms), wearing only a loin cloth, with icy cold towels placed over their shoulders. If the snow melts and the water from the towel evaporates, and the students remain of pink complexion, they pass the test. If the student turns blue, and the snow does not melt, he or she fails .
Qigong grandmaster Shou-Yu Liang, in his book Qigong Empowerment, gives an description of the spiritual flame exercise. The exercise involves visualizing a burning furnace in the solar plexus, and repeated exhalations of blue smoke. According to Liang, this must be practiced for months or years until the body can heat itself almost without limit. Several TV documentaries have filmed the Tibetan Buddhists practicing the exercise, out in snow storms, naked, and the video footage clearly shows the snow melting around them, along with massive evaporation from the towels. The monks keep a pink complexion, and appear peaceful.
In the former Soviet Union, yoga was banned, perhaps because authorities feared its power and influence. There is a well known story of a man who was to be executed by spending the night in a freezing meat locker. When the man emerged the next day unharmed, the Soviet authorities immediately accused him of using yoga!
In Pranayama: La Dynamique du Souffle, the author relates an anecdote of one yogi’s visit to the U.S.S.R. to train cosmonauts in yoga. The Soviet officials who met Swami Dhirendra Brahmachari on the tarmac—in Moscow with winter in full swing—were no doubt perplexed when they saw him disembark from the Air India flight clad only in a thin muslin shift. One charitable official offered his thick wool coat to the yogi, who smiling, refused and said, “I make my own internal heat when I need it.” 
So if you don’t like the methods I’ve outlined in this article, there is always another way.
One Final Word
If ever you come to Canada for some freediving au froid, expect heated ice-fishing huts, rum and extra-wide holes in the ice; night dives with bioluminescence; lots of talk about how cold it was (or how no one took any notice, depending on who you’re trying to impress); sympathy from other freedivers and blank incomprehension from everyone else.
Otherwise, see you in the Tropics!
 Liang, Shou-Yu. Qigong Empowerment: A Guide to Medical, Taoist, Buddhist, Wushu Energy Cultivation. Way of the Dragon: December, 1996.
 Van Lysbeth, Andre. Pranayama: la dynamique du souffle. Flammarion: 1971.
For links to references, please contact Peter Scott by email.