The physiology of cleaning from the inside out

excessive sweating


I’ve written elsewhere (https://secondsixty.substack.com/p/water) about why we don’t need to drink the copious amounts of water the health experts recommend. Here I would like to discuss the benefits of running huge amounts of water through your body, mostly through sweat.

When you drink large amounts of water, it is absorbed into the blood stream, expanding the volume which triggers reflexes to increase diuresis in order to normalize the vascular compartment. Diluting the blood can have serious deleterious consequences from rupture of red blood cells to relative hyponatremia (low sodium) which can cause central demyelination, permanently damaging the central nervous system.

Just drinking water doesn’t get the water to where it does a body good – the extracellular compartment (the water outside the blood surrounding the cells.) Under normal conditions, the water you drink goes right out through the kidneys, bypassing the rest of the body.

To get the water where it needs to go, you have to draw it out of the capillaries. It doesn’t just flow there. Water follows salt, so the concentration of salt and other dissolved solids in the extracellular space has to be higher than in the blood to make that happen.

One of the ways to suck the water out of the space around the cells, concentrating the fluid around the cells, is through sweating. Since this space at 10.5 liters in a 70 kg man is larger than the intercellular space (8 liters) or the plasma (3.5 liters), it is the most significant reservoir for stored water. It’s everybody’s “camel hump.”

In addition, this space which bathes the cells is the medium through which nutrition and wastes must pass. Exchange is enhanced by adequate fluids and diminished when the interstitial space shrinks, which is common in the elderly. (I’ve treated many elderly patients who seemed at death’s door only to completely normalize with nothing more than administering water.)

The amount of water that can be passed through the body is surprising. I’ve measured a whole liter every 15 minutes in the sauna. Athletes like boxers and wrestlers who have to make weight often use the sauna to drastically eliminate water.

The sweat carries toxins, which is good, but it can also waste electrolytes. This is the rationale behind sports drinks like Gatorade. What is not adequately appreciated is that the body adjusts to conserve salt after a few days. Paul Bragg, the influential naturopath and fasting advocate of the last century used to hike Death Valley and invite healthy athletes to accompany him. He fasted on nothing but pure water while the athletes could eat and drink whatever they wanted and drank electrolyte replacement beverages or took salt tablets. (Salt tablets were popular among athletes even into the 1960s and beyond.) The athletes never made the whole 20-mile hike while the elderly, fasting, pure-water-drinking Bragg made it easily every time.

In WWII, the Allies were given salt tablets in North Africa and often suffered from heat exhaustion. Rommel’s German soldiers did not and survived the heat much better than their opponents.

Sir Richard Burton, the famous explorer of the 1800s spend much time with the Bedouins and marveled at how they survived on so little water. He reported that you just get used to feeling thirsty and move about during the coolest hours – at night – and sleep during the day under shade and wearing loose clothing.

Fast forward to the Gulf wars of recent memory. Contrast the US soldier consuming 1 ½ gallons of water a day wearing a modern combat uniform and carrying 43 lbs. of equipment and body armor plus a weapon with the Arab native who carries maybe a quart of water in a bottle and dresses in traditional clothing.

The point I’m making is that the body can adapt to preserve what it needs even while sweating out copious amounts of water. You don’t need electrolyte drinks. The minerals you get in a plant-based, whole foods diet is more than adequate.

But the elimination of toxins from the body is greatly enhanced by sweating, much more than simple urination, which mostly maintains blood volume and pressure.


I’m a huge fan of the traditional Finnish sauna, which is an ancient ritual of sweating alone and with friends. The sauna is as holy as a church to the Finns. So, I was reluctant to accept that an infrared sauna might be superior to the traditional sauna in any way. But a few facts stand out: Infrared heat penetrates deeper than simple convection of the traditional sauna, affecting the deeper tissues under the skin. More toxins are eliminated in the sweat produced by an infrared sauna. Much more, in fact. The infrared sauna is also much cheaper to heat and, being dry without the pouring of water on the hot rocks, is easier to maintain and lasts longer.

How to use the sauna safely and effectively

The purpose of the sauna is to sweat, so you should sip water constantly. Huge glasses at once don’t suffuse to the tissues and the large surges of water will mostly pass through the kidneys, so sip water slowly.

Sip only water, not electrolyte drinks or beer, which will stress your system unnecessarily. Drink beer or juice afterwards if you like, but not during the experience.

Don’t wear anything in the sauna except a towel. Microorganisms need three things to thrive and cause skin problems: heat, dampness and darkness. A swimsuit or other tight clothing supplies all three. The skin needs to be free to release the sweat, dead skin and germs, not trap it against the body.

Stay in as long as comfortable. There is no advantage to making the sauna an ordeal. Your body will adjust to the experience, so be patient and listen to it.

Try the contrast of a hot sauna with a plunge into cold water. The contrast will greatly stimulate circulation and leave you feeling toned and invigorated.

Towel off afterward and even during the experience to remove dead skin and dirt. Don’t use soap, which can have a deleterious effect by eliminating too much oil and drying the skin afterwards. (See my article on the down side of using soap: https://secondsixty.substack.com/p/nope-to-soap)

Don’t sauna every day but give yourself at least a day or two to recover. Once a week works very well.

And finally, don’t use an antiperspirant. Your body needs to sweat to clean itself. Once you cleanse your body, you won’t stink anyway.

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