▁be ▁brought ▁on ▁by ▁mil der ▁activities , ▁such ▁as ▁a ▁gentle ▁walk . ▁In ▁a ▁ 1 9 9 9 ▁study , ▁ 7 8 % ▁of ▁suffer ers ▁reported ▁that ▁attacks ▁were ▁frequently ▁caused ▁by ▁jog ging , ▁whereas ▁ 4 2 % ▁reported ▁sympt oms ▁following ▁br isk ▁walking . ▁ ▁There ▁are ▁several ▁factors ▁outside ▁of ▁food ▁and ▁exercise ▁that ▁have ▁been ▁suggested ▁to ▁increase ▁the ▁risk ▁of ▁an ▁E IA ▁attack . ▁These ▁include ▁the ▁consumption ▁of ▁alco hol , ▁expos ure ▁to ▁pol len , ▁extreme ▁temper atures , ▁the ▁taking ▁of ▁non - st ero idal ▁anti - infl am mat ory ▁dru gs ▁( NS A ID s ), ▁and ▁even ▁certain ▁phases ▁of ▁the ▁men stru al ▁cycle . ▁ ▁Path oph ys i ology ▁ ▁The ▁path oph ys i ology ▁surrounding ▁E IA ▁and ▁F DE IA ▁is ▁not ▁yet ▁fully ▁understood , ▁but ▁there ▁are ▁several ▁theories . ▁ ▁Research ▁shows ▁that ▁hist am ine , ▁a ▁chemical ▁involved ▁in ▁the ▁all erg ic ▁response , ▁plays ▁a ▁key ▁role ▁in ▁E IA . ▁In cre ased ▁hist am ine ▁levels ▁in ▁the ▁blood ▁pl asma ▁have ▁been ▁recorded ▁during ▁inc idents ▁of ▁both ▁E IA ▁and ▁F DE IA . ▁Mor ph ological ▁changes ▁in ▁m ast ▁cells ▁in ▁the ▁skin ▁of ▁E IA ▁patients ▁have ▁been ▁observed ▁following ▁exercise , ▁and ▁are ▁compar able ▁to ▁changes ▁occurr ing ▁in ▁at op ic ▁patients ▁following ▁expos ure ▁to ▁an ▁aller