Endorphin Cocktail

The human body naturally produces endorphins, endogenous opioid peptides that resemble opiates such as morphine and heroin. Prevailing sentiment credits endorphins as the principal trigger for the mild euphoric sensation known as "runner's high."  As with so many of the undisputed truths of my youth, this truth is now disputed.  In a clinical study led by Michael Siebers, endorphins are definitively ruled out as a potential contributor.  Apparently, the endorphin molecule is unable to pass the blood-brain barrier.  However, help is at hand.  The new likely suspect for the pleasant feeling are endocannabinoids.

Whatever the biochemical explanation, Swimming in San Francisco Bay triggers release of a cocktail of related analgesics at least five different ways. Is it any wonder that more than 2,000 people belong to the Dolphin and South End Rowing clubs?

Aerobic exercise is the most well-known trigger. More commonly called "runner's high," endocannabinoids (probably) are released during moderate to extreme exertion when breathing is difficult. Swimming a mile or more at good speed certainly fits this description. When the weather is stormy and/or windy, breathing is extra difficult. This could explain why so many find heightened enjoyment swimming in bumpy water.

Aesthetics is a lesser-known trigger. Every day in the Bay is a distinct immersion in natural loveliness. The stream of phosphorescence as the lead arm slices into the clear yet inky water well before daylight. The full moon setting over the Golden Gate bridge as the sun rises over Coit Tower. A flight of pelicans coursing through the sky. A container ship slowly engulfed and disappearing into a dense and mysterious fog. These are but a few examples of what the Japanese might term "Yugen." Daily contemplation of this transient and stark beauty trigger spurts of dopamine, serotonin, oxytocin.  These chemicals rule when it comes to stimulating our pleasure centers.

Fear certainly plays a role in mixing the endorphin cocktail. Just entering and exiting the water during periods of high, crashing surf is enough to evoke a "fight or flight" response. Critters can also play a frightening role. Stinging nettles sometimes congregate in the bay. These purple-brown jellyfish the size of a large dinner plate deliver a ferocious prickle that has prompted several club members to keep a bottle of vinegar in their locker. Raging pinnipeds are another source of concern. Normally we share the bay peacefully. Occasionally, however, a rogue seal or sea lion will go on a rampage, inflicting vicious bites that require stitches and powerful antibiotics. Any of these can trigger a squirt of adrenaline, a hormone secreted by adrenal glands in conditions of stress. Today, I ran headlong into a full, floating, plastic gallon milk jug. That was a rude surprise and a serious increase in my rate of blood circulation, breathing, and carbohydrate metabolism.  Still, it wasn't as scary as swiping a handful of moon jellyfish (harmless, but reminiscent of grabbing a decapitated head.) Then, there's the self-inflicted fear factor. Swimming under the piers, through the roundhouse, or anywhere near barnacle-encrusted buoys and breakwaters is a sure way to make the heart race just a little faster.

Of course, immersion in the cold all by itself stimulates the pleasure centers. The Rejuvenation Lounge website lists twelve reasons to take cold showers:

1. Mood booster
2. Releases stress and tension
3. Improves circulation
4. Flushes out toxins
5. Clears negativity from your aura
6. Cleanses your chakras
7. Strengthens your immune system
8. Speeds up the healing process
9. Restores your energy levels
10. Brings you fully into your body and fully into the present moment
11. Cheap and environmentally friendly
12. Clears negative thinking

I'm no expert on chakras, auras, or the immune system, but the rest of this seems right on the money to me.

When the water is truly cold, a prolonged stay in the sauna is especially welcome. Leaving too soon leads to the physical sensation known as "afterdrop."  Afterdrop is a continued cooling of a person's core temperature during the initial stages of rewarming from hypothermia.  It is attributed to the return of cold blood from the extremities to the core due to peripheral vasodilation.  In a nutshell, this means,  "stay in the sauna until you get warm or you'll regret it."  The resulting enforced collegiality makes us prisoners of one another and slaves to each others' stories, opinions, and statements of true fact.  And some of the facts are actually true.  The clubs are populated by a mix of people from walks of life ranging from homeless to venture capitalist and from research scientist to commercial fisher.  Police, firefighters, physical therapists, astronomers, salespeople, gardeners, architects, actors, musicians, techies, lawyers, doctors.  Its a cornucopia of backgrounds and the range of expertise is vast. At its best, this positive social interaction is the fifth vehicle for increasing chemical levels and fostering an addiction to cold water swimming.  Scientists have shown that the chemical signal dopamine plays an unexpected role in social interactions. Mary Catherine O'Connor reports on the Smart Planet website that the key to the success of Facebook is the designer's focus on stimulating friendship and collaboration.  The designers are trying to mimic the power of serotonin, another neurotransmitter that contributes to feelings of happiness in humans.

As powerful as this cocktail is on its own, a sixth endorphin stimulus is sexual arousal.  However, this dopamine trigger is not as reliable on a daily basis as the other five and a discussion of the South End birthday swims and the wearing of birthday suits is a topic all by itself.