As I’ve mentioned in other posts, we moved a year and a half ago where my gym has a spa sized-cold plunge they keep chilled to around 40-45F for the guys. I experimented with it for years, but after a few months with the drive & downtown parking, I gave it up in favor of a local swim & racket club. The pools are about 80.
But now I have a cold plunge, again, as of this morning.
It’s a livestock watering trough made by Rubbermade. It’s 150 gallons, a bit shorter but wider than another 150 gal trough I’d been looking at for $150. Got this at a local feed & supply place and considering shipping cost, came out about a wash at $200.
Then I went and got a pool thermometer, and two 5-gallon buckets from Home Depot, now sitting in my box freezer 4/5ths filled with water.
The tap water came out at 50 degrees exactly and when full, it was 51, which I attribute to the temp of the plastic raising the water temp a bit.
And then I couldn’t wait any longer, and I got right in.
It was funny because, in just stepping in I was filled with horror. This isn’t going to be fun! But I just sunk right down, the trough overflowed to the point where I could sit, feet exactly touching the other side, and the water comes up to my chin. It’s like this was designed to my own bodily specs.
Within 30 seconds I was totally fine and by 1 minute, actually warm and didn’t feel cold until well after 10 minutes. Slight quivers began at the 20-minute mark.
I got out when I went to check my time, took my hands out of the water to go for my iPhone and noticed diminished motor control.
But all in all, a cinch, very uplifting. A few observations. This was far easier than the cold plunge at my gym. Two reasons, other than that it was colder, I think. First, it was always my practice to completely submerge initially, getting my head wet & cold. Didn’t do that here. Head stayed dry. Second, the gym had a couple of circulating jets, so water is moving across your body. I found that to the extent I remained motionless in this tub, I was remarkably unperturbed. You’re still losing lots of heat, it’s just at a slightly lower rate because you have a “boundary layer” near your skin. You can verify this by moving around and the water feels very cold, suddenly.
Alright, so how many calories did I burn in 26 minutes, you thermodynamicists? When I got out, I stirred up the water and the thermometer read about 52.3 degrees, so perhaps I raised the temp of the water 1.3 degrees. Now, I weigh 180, the human head is about 8% of mass, so let’s say I was displacing 166 pounds of water, or 20 gallons. So, 150 gallon tank filled to the brim, I raised 130 gallons by 1.3 degrees F.
Next time I’ll use a digital thermometer to get a more exact idea of the temperature increase.