Run­ning stresses the heart, but don’t stress out

StarMetro Vancouver - - THE KIT - Amby Bur­foot

A new “Re­search Let­ter” pub­lished in the Amer­i­can Heart As­so­ci­a­tion’s jour­nal Cir­cu­la­tion raises the old fear that run­ning long dis­tances — par­tic­u­larly the 42.2-km marathon — could be bad for am­a­teur run­ners. But ac­cord­ing to sev­eral ex­perts, in­clud­ing the pa­per’s au­thor, would-be marathon­ers should not worry that they are on the road to a heart at­tack or heart dis­ease, though it is smart not to at­tempt the marathon dis­tance un­til you have trained suf­fi­ciently.

A group of Span­ish phys­i­ol­o­gists re­ported that “the strain im­posed on the my­ocardium by com­pet­ing a full marathon is much greater com­pared with other dis­tances such as the half-marathon or 10-km races.” They came to that con­clu­sion by mea­sur­ing the same pro­teins in run­ners’ blood that doc­tors look at to di­ag­nose heart at­tacks. The biomark­ers — car­diac tro­ponins — were el­e­vated in all 63 run­ners (39 women and 24 men, with an av­er­age age of 37) af­ter com­plet­ing their races, Stud­ies sug­gests elite run­ners shouldn’t worry that they are headed for a heart at­tack, but am­a­teur run­ners should ease into long dis­tances.

but par­tic­u­larly so among the marathon run­ners.

But the Span­ish team made no claims about heart at­tack or heart dis­ease risks among the marathon run­ners. In­deed, the Let­ter notes that “the re­lease of car­diac tro­ponins af­ter ex­er­cise may not be in­dica­tive of any car­dio­vas­cu­lar dys­func­tion.”

This is pre­cisely the find­ing of other stud­ies pub­lished over the last decade, in­clud­ing a hand­ful in Cir­cu­la­tion, a sci­en­tific jour­nal pub­lished

for the Amer­i­can Heart As­so­ci­a­tion. “I don’t see any­thing new here, and the in­creased like­li­hood of a tro­ponin bump with marathon vs. shorter dis­tances has been well de­scribed be­fore,” Malissa Wood, of Bos­ton’s Mas­sachusetts Gen­eral Hospi­tal, said by email.

Wood was a co-au­thor of the first ma­jor pa­per on the sub­ject, which ap­peared in Cir­cu­la­tion in 2006. That in­ves­ti­ga­tion fol­lowed 60 nonelite par­tic­i­pants in the 2004 and 2005 Bos­ton Marathons. All had un­mea­sur­able tro­ponin be­fore the marathon, but more than 60 per cent had lev­els greater than 99 per cent of nor­mal post marathon. Still, the pa­per con­cluded: “There are no data to sug­gest that there are long-term se­que­lae to the in­crease in biomark­ers.” In other words, no sub­se­quent heart dam­age.

Paul Thomp­son, chief of car­di­ol­ogy at Hart­ford Hospi­tal in Con­necti­cut, has been re­search­ing the ex­er­cise­heart con­nec­tion for 40 years. “We’ve long known that tro­ponins in­crease af­ter ex­er­cise,” he said in an email. “The new Re­search Let­ter’s small con­tri­bu­tion is to sug­gest that long-term ef­fects should be stud­ied. We all agree with this, and lots of groups, in­clud­ing ours in Hart­ford, are al­ready do­ing this.”

“Cur­rent en­durance ath­letes should not be wor­ried,” said Thomp­son. “They al­ways live longer than their seden­tary peers, and there re­mains no con­clu­sive ev­i­dence that their ex­er­cise is dan­ger­ous.”

More on the find­ings at thes­


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