2013 Polar Bear Plunge La Jolla Shores.

My good neighbor Kevin and I are walking into the ocean, towards the white waves of a gray winter’s day. Water temp is high fifties. Knife-like breeze makes the air feel colder than the water. “OMG!” says this girl, huddling with her boyfriend against the wind. But here’s the thing: once you’ve decided to jump in, it already doesn’t feel so bad.

Kevin and I started this daily ocean body-surf routine back in the summer, and the interesting thing is that as the temps have dropped, both beneath and above the water’s surface, we’ve kind of gotten used to them — once we’ve taken the initial plunge, anyway, and as long as we don’t keep our heads underwater long enough to get an “ice cream” headache. (Normally, you stay under as long as you can hold your breath. That way, the wave can carry you as far as possible. If you try to bob your head up, you’ll lose the momentum.)

Whatever, I swear that after a couple of waves, the cold just doesn’t feel cold like it does when you’re standing on the shore anticipating it. Once you’ve taken the plunge, ridden your compulsory three decent waves, and come out, it’s like, “Cold? What cold?”

“I always feel better, coming out of the water,” says Kevin. “And not just because we can strut our thing in front of these landlubbers.” The literature backs him up. Cold water swimming gives you a natural high, improves your circulation, increases your libido(!), burns calories, reduces stress, boosts your immune system, and activates your “feel-good” endorphins. Not only that, but today, Kevin is talking all about “anticipatory thermogenesis.” “It’s a Pavlovian response to the expectation of going into cold water,” he says. “Your body actually heats up inside when it’s expecting to lose a lot of heat. That’s a brand-new discovery.”

According to the website Openwaterpedia.com, anticipatory thermogenesis is “the ability to mentally generate an increase in one’s core body temperature.” Professor Tim Noakes of the University of Cape Town noticed that famed frozen-water swimmer Lewis Pugh was able to raise his core temperature by up to 2 degrees centigrade as he prepared to enter Antarctic waters on one of his many long-distance attempts. Pugh is the first swimmer in whom human researchers have ever noted this. On the other hand, Russian and Scandinavian “polar bears” have been doing crazy frozen swimming for years.

So, okay, our San Diego swims are in no such league, but I swear, the pain of cold water definitely diminishes the more you do it, just as the pleasure of strutting your stuff out of the water — when everyone’s looking at you like you’re a madman — keeps on rising.

“Ready?” says Kevin, as we shake ourselves off, ready for the walk back. “Three, two, one, strut!”