Purpose：Exerciseisphysicalactivitythatisplanned,structured,andrepetitiveforthepurposeofconditioningthebody.Exerciseisessentialforimprovingoverallhealth,maintainingfitness,andhelpingtopreventthedevelopmentofobesity,hypertension,andcardiovasculardisease.

　　Thewholeessayasfollows:

　　Exerciseisphysicalactivitythatisplanned,structured,andrepetitiveforthepurposeofconditioningthebody.Exerciseconsistsofcardiovascularconditioning,strengthandresistancetraining,andflexibility.

　　Exerciseisessentialforimprovingoverallhealth,maintainingfitness,andhelpingtopreventthedevelopmentofobesity,hypertension,andcardiovasculardisease.SurveysconductedbytheCentersforDiseaseControlandPrevention(CDC)indicatethat61.5percentofchildrenagednineto13yearsdonotparticipateinanyorganizedphysicalactivity(forexample,sports,danceclasses)and22.6percentarenotphysicallyactiveduringtheirfreetime.AccordingtotheAmericanObesityAssociation,approximately30percentofchildrenandadolescentsagedsixto19yearsareoverweightand15percentareobese.

　　Asedentarylifestyleandexcesscaloricconsumptionaretheprimarycausesofthisincreaseinoverweightandobesity;regularexerciseisconsideredanimportantfactorincontrollingweight.Overweightandobesechildrenandadolescentsareathigherriskofdevelopingseveralmedicalconditions,includingthefollowing:

　　•asthma

　　•diabetes

　　•hypertension

　　•orthopediccomplications,suchashipandkneepainandlimitedrangeofmotion

　　•cardiovasculardisease

　　•highcholesterol

　　•sleepapnea

　　•psychosocialdisorders,suchasdepression,negativebodyimage,andeatingdisorders

　　Clinicalstudieshaveshownthatregularexercisehasnumerousbenefits,includingthefollowing:

　　•preventingweightgainandmaintaininghealthyweight

　　•reducingbloodpressureandcholesterol

　　•improvingcoordination

　　•improvingself-esteemandself-confidence

　　•decreasingtheriskofdevelopingdiabetes,cardiovasculardisease,andcertaintypesofcancer

　　•increasedlifeexpectancy