Ounce of Prevention: Healthy sweating

The skin of the average person is embedded with from two to five million sweat glands, and humans can produce as much as three litres of sweat per hour.

We have two different types of sweat glands - eccrine and apocrine. Eccrine glands produce a watery sweat and are found all over the body but more on the face, hands and feet. This sweat, mostly water, also contains sodium, some potassium, chloride, calcium and magnesium, as well as traces of copper, zinc, iron and other chemicals

Apocrine sweat glands produce a thicker sweat that contains fatty acids, urea and ammonia. They are found in the hair follicles in the scalp, armpits, pubic and genital areas. Stress triggers the apocrine glands to secrete this fatty sweat which bacterial action can give an unpleasant odor.

How much a person sweats depends on factors like age, gender, body temperature, and level of exertion, anxiety or obesity. Exercise and heat are the most common triggers of perspiration because sweating's main role is to cool down the body. However, sweating offers several other benefits.

SWEAT ELIMINATES TOXINS

Sweat is an important cleanser. Research demonstrates that sweat releases toxins from the body, including the dangerous heavy metals lead, cadmium, mercury and arsenic.

Arsenic-containing compounds, although highly toxic, have so many industrial uses - from insecticides to wood preservatives - that their presence is now inescapable. Arsenic is even in our water and food. Contamination starts from arsenic tainted groundwater, which when used to irrigate food crops, allows arsenic into the food chain.

Mercury, a poisonous liquid metal, can be inhaled, ingested or absorbed through the skin. The most common sources of mercury are from contaminated seafood, dental amalgam fillings, and some vaccines.

Cadmium promotes cancer and can cause kidney failure and high blood pressure. We intake cadmium mostly by eating crops grown on soil saturated with man-made fertilisers, and from landfills contaminated with old cadmium batteries.

Lead occurs naturally in the earth but is toxic to all systems in the body. Lead is found in certain types of kitchen utensils, batteries, gasolene fumes and some paints. Fortunately, these toxic metals are readily excreted through sweat.

SWEAT PROTECTS THE KIDNEYS

Sweating reduces the salt and calcium content of the urine and can reduce the risk of kidney stones. A study published by the American Society of Nephrology found that increased physical activity (more sweat) plus lower food consumption cut kidney stone formation by 31 per cent. Sweating increases thirst, leading to greater water intake. The more water consumed, the less the risk of kidney stones. Because some sweat contains urea and ammonia, the burden on the kidneys to eliminate these substances is less.

SWEAT FIGHTS GERMS

Researchers have discovered a powerful natural antibiotic in sweat called dermcidin. Dermcidin can limit the bacterial population on our skin, and reduce our risk of infection. Excessive skin washing can remove this natural protective barrier and may limit your defence against germs.

SWEAT HELPS HEALING

Scientists discovered that sweat glands play a role in wound healing and the recovery from scrapes, burns, and ulcers. In a study published in the American Journal of Pathology, researchers found that eccrine sweat glands store a reservoir of stem cells that rapidly activate healing when a wound occurs. The more we sweat, the more active our sweat glands are. These findings may lead to better therapies for those with chronic skin ulcers.

HEALTHY SWEATING TIPS

Exercise more: Along with its many other health benefits, brisk exercise increases the body's metabolic rate and temperature resulting in sweating. The more regularly one exercises, the more active the sweat glands become, and the more easily you will sweat. Consistency and intensity are the critical factors here. By the way, Japanese research shows that women need to exercise harder than men to work up a good sweat.

Sunshine regularly: Apart from the production of vitamin D3 when the skin is directly exposed to sunshine, sun exposure increases sweating. It is ideal to exercise in a sunny environment with as much of your skin exposed as possible.

Use saunas and spas: Sauna baths are powerful sweat inducers, and a special kind of sauna called an infrared sauna is particularly therapeutic, especially for detoxification purposes. Natural hot-water spas or a hot bath with added Epsom salts also promote healthy sweating.

Drink more fluids: Water helps you detoxify, and drinking before you exercise is like priming your sweat glands. Drink before, during, and after workout to prevent dehydration and encourage sweating. Drinking green tea will also increase sweating, particularly during exercise.

Wear the right clothing: Choose 'breathable' workout clothes made of fabrics like cotton that move the moisture away from the skin. You do not want to have toxin-rich sweat against your skin for long. The popular plastic 'sweat garments' may not be so healthy!

Skip the antiperspirant: Allow the skin under your arms to sweat, particularly when you work out, as this is one of the body's key areas for toxin removal. For optimal detoxification, and to prevent the sweat from having time to develop an odour, shower as soon as possible after you have exercised.

About two per cent of the general population has the problem of excessive sweating (hyperhidrosis), but that's the subject for another discussion.

- You may email Dr Vendryes at tonyvendryes@gmail.com or listen to 'An Ounce of Prevention' on POWER 106 FM on Fridays at

8:15 p.m. Details of his books and articles are available at www.tonyvendryes.com.