Happiness may protect against heart disease

Feb. 21, 2010
Courtesy European Society of Cardiology
and World Science staff

Peo­ple who are usu­ally hap­py, en­thu­si­as­tic and con­tent are less likely than oth­ers to de­vel­op heart ill­ness, ac­cord­ing to a new stu­dy.

The scientists involved say the stu­dy, pub­lished in the Eu­ro­pe­an Heart Jour­nal, is the first to show an in­de­pend­ent rela­t­ion­ship be­tween pos­i­tive emo­tions and cor­o­nary heart dis­ease, the most com­mon type of heart di­sease. Pre­vi­ous stud­ies had linked hap­pi­ness with long life, but the ex­act rea­sons for that as­socia­t­ion are un­cer­tain.

Ka­rina Da­vid­son of Co­lum­bia Uni­vers­ity Med­i­cal Cen­ter in New York, who led the new stu­dy, said it sug­gests heart dis­ease might be in some de­gree pre­venta­ble through pos­i­tive emo­tions. But it would be prem­a­ture to make clin­i­cal rec­om­menda­t­ions with­out fur­ther stu­dy, she added.

“We des­pe­r­ately need rig­or­ous clin­i­cal tri­als in this ar­ea. If the tri­als sup­port our find­ings, then these re­sults will be in­credibly im­por­tant in de­scrib­ing spe­cif­ic­ally what clin­i­cians and/or pa­tients could do to im­prove health,” said Da­vid­son, who di­rects Co­lum­bi­a’s Cen­ter for Be­hav­ior­al Car­di­o­vas­cu­lar Health.

Over 10 years, Da­vid­son and col­leagues tracked 1,739 healthy adults, split about evenly be­tween men and wom­en, par­ti­ci­pat­ing in a study known as the 1995 No­va Sco­tia Health Sur­vey. At the start, trained nurses as­sessed the par­ti­ci­pants’ risk of heart dis­ease and, with both self-reporting and clin­i­cal as­sess­ment, they meas­ured symp­toms of de­pres­sion, hos­til­ity, anx­i­e­ty and the de­gree of ex­pres­sion of pos­i­tive emo­tions, which is known as “pos­i­tive af­fec­t.”

Pos­i­tive af­fect is de­fined as the ex­pe­ri­ence of pleas­ur­a­ble emo­tions such as joy, hap­pi­ness, ex­cite­ment, en­thu­si­asm and con­tentment. These feel­ings can be tran­sient, but they are usu­ally sta­ble and trait-like, par­tic­u­larly in adult­hood, ac­cord­ing to re­search­ers. Pos­i­tive af­fect is largely in­de­pend­ent of neg­a­tive af­fect, so that some­one who is gen­er­ally a hap­py, con­tented pe­r­son can al­so be oc­ca­sion­ally anx­ious, an­gry or de­pressed.

Af­ter tak­ing ac­count of age, sex, car­di­o­vas­cu­lar risk fac­tors and neg­a­tive emo­tions, the sci­en­tists found that in­creased pos­i­tive af­fect pre­dicted less risk of heart dis­ease by 22 per­cent per point on a five-point scale meas­ur­ing lev­els of pos­i­tive af­fect ex­pres­sion. “We al­so found that if some­one, who was usu­ally pos­i­tive, had some de­pres­sive symp­toms at the time of the sur­vey, this did not af­fect their over­all low­er risk of heart dis­ease,” Da­vid­son said. “As far as we know, this is the first pro­spec­tive study to ex­am­ine the rela­t­ion­ship be­tween clin­ic­ally-as­sessed pos­i­tive af­fect and heart dis­ease.”

“We have sev­er­al pos­si­ble ex­plana­t­ions” for the ef­fect, said Da­vid­son. “First, those with pos­i­tive af­fect may have long­er pe­riods of rest or re­laxa­t­ion phys­i­o­logic­al­ly,” mak­ing their bod­ies bet­ter able to reg­u­late blood pres­sure and heart rate. “Sec­ond, those with pos­i­tive af­fect may re­cov­er more quickly from stres­sors, and may not spend as much time ‘re-living’ them, which in turn seems to cause phys­i­o­log­ical dam­age. This is spec­u­la­tive, as we are just be­gin­ning to ex­plore why pos­i­tive emo­tions and hap­pi­ness have pos­i­tive health ben­e­fits.”