Sauna Ceremonialbathing has existed for thousands of years and has many forms,one of which isthe sauna.The Finns have perfected the steam bath,or sauna,which may be

taken,usually in anenclosed room，by pouringwater over hot rocks or as a dry heat bath.The Japanese,Greeks,Turks andRussians as well as Native Amencans have forms of

the sweat bath intheir bathing rituals.Dry heat and steam baths had advocates in ancient Romeand pre-Columbian Americans used sweat lodges（发汗帐篷）. The earliest

saunas were probablyunderground caves heated by a fire that naturally filled with smoke as chimneymaking was unknown at that time.A fire kept in a fire-pit would heat the

rock walls of thecave. After reaching full heat,the smoke was let out of the cave and the stoneswould retain heat for several hours. A few people today say that the smoke

sauna,"savusauna",isthe only true sauna experience and that all saunas should have at least a back加und odor（气味）orsmoke.Today most saunas use electric stoves,

although gas andwood-burning stoves are available. Saunas are relaxing and stressrelieving.Those with muscle aches or arthritis may find that the heat relaxesmuscles and

relieves pain andinflammation（炎症）.Asthma（哮喘）patients find that the heat enlarges air passageways of the lung andfacilitates breathing.Saunas do not cure the

common cold but theymay help to alleviate congestion and speed recovery time.The body's coretemperature usually rises 1-2 degrees while in the sauna,thus imitating a

slight fever.Thesauna could be considered to follow the old saying"feed a cold,starve afever".The regular use of a sauna may decrease the likelihood of getting acold in the

first place. Saunais good for your skin as the blood flow to the skin increases and sweatingoccurs.Adults sweat about 2 lbs（磅）of water per hour on average in a sauna.A

good sweat removesdirt and grime from pores（毛孔）and gives the skin a healthy glow.The loss in water weight istemporary as the body's physiological mechanisms will

quickly restoreproper volumes.The cardiovascular（心血管的）system gets a work out as the heart must pump harder and faster tomove blood to the surface for heat

exchange.Heart ratemay increase from 72 beats per minute on average to 100-150 beats per minute. Anormal heart can handle these stresses but those with heart trouble

wishing to begin touse a sauna should seek a doctor's advice.The elderly and those with diabetesshould check with their doctor prior to beginning to take saunas.Pregnant

women should nottake saunas,particularly in the first three months.Indeed,everyone juststarting out should take short sessions at first to become accustomed to thistype of

bath.

Who are advisednot to take a sauna?

A.Elderly people.

B.Pregnant women.

C.People with hearttrouble.

D.All of the above.