Ceremonial (仪式性的) bathing has existed for thousands of years and has many forms, one of which is the sauna.The Finns have perfected the steam bath, or sauna, which may be taken, usually in an enclosed room, by pouring water over hot rocks or as a dry heat bath. The Japanese, Greeks, Turks and Russians as well as Native Americans have forms of the sweat bath in their bathing rituals. (46) Dry heat and steam baths had advocates in ancient Rome and pre-Columbian Americans used sweat lodges.
The earliest saunas were probably underground caves heated by a fire that naturally filled with smoke as chimney making was unknown at that time. A fire kept in a fire-pit would heat the rock walls of the cave. After reaching full heat, the smoke was let out of the cave and the stones would retain heat for several hours. A few people today say that the smoke sauna, “savusauna”, is the only true sauna experience and that all saunas should have at least a background odor or smoke. (47) Today most saunas use electric stoves, although gas and wood-burning stoves are available.
Saunas are relaxing and stress relieving.Those with muscle aches or arthritis (关节炎) may find that the heat relaxes muscles and relieves pain and inflammation (炎症). Asthma (气喘) patients find that the heat enlarges air passageways of the lung and facilitates breathing. Saunas do not cure the com#mon cold but they may help to alleviate congestion (阻塞) arid speed recovery time. The body’s core temperature usually rises a 1-2 degrees while in the sauna, thus imitating a slight fever. (48)The sauna could be considered to follow the old saying “feed a cold, starve a fever”. The regular use of a sauna may decrease the likelihood of getting a cold in the first place.
Sauna is good for your skin as the blood flow to the skin increases and sweating occurs. Adults sweat about 2 lbs of water per hour on average in a sauna. A good sweat removes dirt and grime from pores and gives the skin a healthy glow. The loss in water weight is temporary as the body’s physiological mechanisms will quickly restore proper volumes. The cardiovascular system gets a work out as the heart must pump harder and faster to move blood to the surface for heat exchange. (49) Heart rate may increase from 72 beats per minute on average to 100-150 beats per minute.
A normal heart can handle these stresses but those with heart trouble wishing to begin to use a sauna should seek a doctor’s advice. The elderly and those with diabetes should check with their doctor prior to beginning to take saunas. Pregnant women should not take saunas, particularly in the first three months. (50) Indeed, everyone just starting out should take short sessions at first to becom#e accustomed to this type of bath.
Don't Rely on Indirect Evidence
Conversations may be miscalcuting the numbers of the threatened animals such as elephants, say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung(粪)the creatures leave behind.
The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conversation Society (wcs) in New York.
Biologist Katy Payne of Conrell University in Ithaca, New York, agrees. "We really need to know elephant numbers and the evidence that we have is quite indirect" says Payne, who electronically tracks elephants.
Counting elephants from aeroplanes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it's extremely difficult to determine these rates, however, researchers tallying(统计) elephants in one region tend to rely on standard decay rates established elsewhere.
But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. Using the wrong values can lead the census astray(离开正道), says Plumptre.
He said his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Banyang-Mbo Widlife Sanctuary(禁猎区)in Southweat Cameroon. They found that the dung decayed between 55 and 65 percent more slowly than the dung in the rainforests of neighbouring Gabon. If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around.
This could mean estimates in Cameroon are at least twice as high as those derived from decay rates celcalated locally, says Plumptre "However accurate your dung density estimate is the decay rate can severly affect the result."