natural and unexpected death that happens within less than one hour of first symptom occurrence is called sudden death ( 1 - 4 ) .
sudden death is more common among men and the black race ( 5 , 6 ) . in a systematic review based on data related to 1980 - 2007 , annual incidence of sudden cardiac death ( scd ) in the united states varied between 180000 and 450000 ( 7 ) . in some other studies ,
scd rate range was reported 50 - 100 per 100000 of general population in countries such as netherlands , ireland , and china ( 8) .
interestingly , in about 25% of patients who die of coronary artery atherosclerosis , the first sign is sudden death .
after coronary artery diseases , cardiomyopathies including hypertrophic and dilated types are among the second cardiac causes of sudden death ( 1 ) .
dysfunctions of the heart valves , especially aortic stenosis , are considered as other underlying cardiac causes of sudden death ( 9 ) .
hypertrophic cardiomyopathy is the most common cause of sudden death in people under thirty years of age ( 10 ) .
most patients with hypertrophic cardiomyopathy are asymptomatic and death can occur at rest or with mild physical activity , however , sudden death often occurs during intense physical activity ( 10 , 11 ) . in many cases ,
hypertrophic cardiomyopathy is the only autopsy finding in young victims of sudden death and is the most common reason of sudden death during exercise ( 12 ) .
drug abuse ( such as stimulants , anabolic steroids , opioids , and etc . ) , bronchoconstriction , heat stroke , and drowning can be mentioned as non - cardiac causes of sudden death in athletes but cardiac causes are more important ( 9 , 13 - 15 ) . about 69% of sudden deaths in general population
are attributed to cardiovascular diseases , while more than 75% of sudden deaths in athletes are assigned to it ( 13 , 16 ) . to emphasize the importance of this topic , here we review
the forensic reports of all cases of sudden death following exercise , referred to forensic medicine center of tehran , iran , from 2009 to 2014 .
in this cross sectional study , all subjects who were registered to forensic medicine center of tehran , iran , from 2009 to 2014 , as a case of sudden death following exercise were evaluated .
demographic data ( age , sex ) and medical history as well as autopsy and toxicology findings were gathered using deceased profiles , retrospectively .
the protocol of study was approved by the ethics committee of shahid beheshti university of medical sciences .
  14 cases were registered as sudden death following exercise in forensic medicine profiles during the study period . exploring the files of the mentioned deceased , revealed five non - compatible cases in this regard .
the cause of death was homicide in one case ( 4.5 years old boy ) , drowning in another ( 38 year - old female ) , and myocardial infarction in the last three cases ( all above 40 years old ) .
the mean age of the deceased was 28.66  10.86 years ( range : 7  40 ) .
toxicological tests were available for 7 cases , which was positive for tramadol in one case .
only 3 ( 33.3% ) cases had herald signs such as chest pain , syncope , or loss of consciousness .
baseline characteristics and autopsy findings of the studied deceased : year ; na : not available .
in recent years , concerns and interests of the people and physicians regarding causes of sudden death in athletes have impressively increased .
congenital heart defects , hypertrophic cardiomyopathy , coronary artery disease , and myocarditis are among the most prevalent causes of scd in patients under 35 years of age . on the other hand , acquired coronary artery disease is a common cause of sudden death in over 35 year old population ( 13 - 16 ) .
sudden death can occur in approximately all types of sports but it has been more frequently reported in sports like football and basketball . in the current study , most deaths had occurred after football and swimming . in some studies ,
the risk of sudden death following exercise in men has been reported to be 5 times more than women and the findings of this study has demonstrated this matter ( 16 ) .
baggish and colleagues studied cardiovascular screening effects with and without electrocardiography ( ecg ) in the 510 collegiate athletes of united states . involving ecg , compared to its non - use in the screening , increased identification of cardiomyopathy cases , sensitivity of screening program ( from 45.5% to 90.9% ) , and negative predictive value ( from 98.7% to 99.8 % ) ( 17 ) .
mild symptoms such as slight chest pain and other symptoms that indicate heart problems such as exertional dyspnea should be seriously regarded and taught to all people , so that similar cases can be prevented .
the authors of this article recommend asking the necessary questions listed in table 2 for primary screening of at risk patients for sudden death following exercise . in case of any positive answer to the mentioned questions
it should be mentioned that not all cases of sudden death are referred to forensic medicine center for autopsy , especially in cases of clear diagnosis such as acute myocardial infarction or brain insults ( hemorrhagic , ischemic , etc . ) .
although most sudden death victims are asymptomatic until the event , all those who suffer from symptoms such as chest pain , shortness of breath , dizziness , fatigue and irregular heart rate during physical activities , should be screened regarding common probable causes of sudden death .
all authors passed four criteria for authorship contribution based on recommendations of the international committee of medical journal editors .
 introduction : natural and unexpected death that happens within less than one hour of first symptom occurrence is called sudden death . 
 cardiovascular diseases are the main known reason of sudden death and more than 75% of sudden deaths in athletes are assigned to it . 
 here we reported the autopsy results of all cases with sudden death following exercise that were referred to forensic center of tehran , iran , from 2009 to 2014 . 
 methods : in this cross sectional study all subjects who were registered to forensic medicine center of tehran , iran , from 2009 to 2014 , as a case of sudden death following exercise were evaluated . 
 demographic data and medical history as well as autopsy and toxicology findings were retrospectively gathered using profiles of the deceased . 
 results were reported using descriptive analysis . 
 results:14 cases were registered as sudden death following exercise in forensic medicine profiles during the study period . 
 exploring the files of the mentioned deceased , revealed five non - compatible cases in this regard . 
 finally , 9 eligible cases were enrolled ( 88.9% male ) . 
 the mean age of the deceased was 28.66  10.86 years ( range : 7  40 ) . 
 toxicological tests were available for 7 cases , one of which was positive for tramadol . 
 sudden death following football was reported most frequently ( 44.4% ) . 
 only 3 ( 33.3% ) cases had herald signs such as chest pain , syncope , or loss of consciousness . 
 1 case ( 11.11% ) had a positive history of sudden death in relatives . 
 conclusion : although most sudden death victims are asymptomatic until the event , all those who suffer from symptoms such as chest pain , shortness of breath , dizziness , fatigue and irregular heart rate during physical activities , should be screened regarding common probable causes of sudden death . 
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