During half the year in Southern California, the Pacific Ocean is pretty cold as the water gets in the low 50′s. Just by going in knee deep, most peoples ankles already go numb. And if you keep going in, it’s very possible you may start hyperventilating once the water hits your face. So it’s very rare to see people in the water without wetsuits.
But I figured out a pretty nice way of getting control over all these things…
I basically do 10–15 minutes of yoga on the sand to warm my body up. The trick is to really focus on inhaling when you do a move and exhaling when you do the next move. This will cause your breathing to be deep, slow and relaxed. That’s the trick to creating a harmoniously moving meditation. The physical yoga moves are good enough to get the heart pumping more and warming up the body but the breathing is what helps keep everything nice and steady. Once your breathing is calm and cool and centered for several minutes, this effect continues and helps to remain calm when you enter the water.
Contrast this with running (or any other cardio exercise) that will definitely increase your body temperature but your breathing won’t be calm whatsoever. You’ll actually be panting and that can immediately turn to hyperventilation when cold water hits your face.
So once I go in the water, I get out after just a couple minutes, do some more yoga to warm back up, and then go back in. The second time always feels dramatically warmer than the first. Then I repeat this again because the 3rd time feels dramatically warmer than the second. So much so that this is the time I could spend up to 10–30 minutes in the SoCal water in the winter time and not feel cold at all. I even just lie on my back and totally surrender to the ocean keeping myself calm cool and collected.
Hope that helps.