Individuals whose resting heart rates rise over a ten-year-period have a higher risk of dying early from any cause, as well as a greater likelihood of developing ischemic heart disease, compared to other people, researchers from the Norwegian University of Science and Technology, Norway, reported in JAMA (Journal of the American Medical Association), after carrying out a study on almost 30,000 apparently healthy adults.
The authors explained, as background information, that early studies had pointed towards a link between elevated RHR (high resting heart rate) and a higher chance of developing cardiovascular disease, as well as a higher death rate in the general population, even after taking into account several risk factors. However, no studies had looked into whether long-term RHR impacted on death risk of ischemic heart disease.
Javaid Nauman, Ph.D. and team set out to determine whether RHR changes influenced the risk of death from ischemic heart disease in a sample study of 13,499 adult males and 15,826 females - none of them had any history of cardiovascular disease.
All the participants' resting heart rates were measured twice, one ten years after the other, with the second being measured between August 1995 and June 1997. They were all followed up until December 2008. Sixty participants dropped out of the study because they had left the country.
3,038 of them died during the 12-year follow-up. 975 of all the deaths were caused by cardiovascular disease and 388 by ischemic heart disease.
They found that those with a resting heart rate that rose from under 70 beats per minutes and then rose to over 85 within ten years had a 90% greater chance of death from ischemic heart disease compared to those whose resting heart rates stayed below 70 throughout the whole study period.
The risk of developing ischemic heart disease was 80% greater for those whose heartbeats were between 70 and 85 beats per minutes initially, and rose to over 85 beats per minute by the end of the ten years.
They found a similar correlation with all causes of death linked to RHR changes as were observed for ischemic heart disease mortality; but add that the effect was not as strong.
No benefit was found in participants whose RHR went down over the ten years (with regards to IHD mortality).
The authors wrote:
"As expected from the good general health of the study participants, the observed moderate-to-strong increases in relative risk corresponded to small risk increases in absolute terms. However, it is not clear to what extent we can extrapolate our findings to less healthy individuals in whom the underlying risk is likely to be higher.
Our findings provide further support for the hypothesis that RHR may be an important prognostic marker for IHD and total mortality. Information on RHR and its time-related changes are easy to obtain and follow-up and may be useful in identifying asymptomatic people who could benefit from measures of primary prevention, but further study in this area is warranted."
What is Ischemic Heart Disease?Ischemic heart disease means lack of blood supply to the heart muscle. This is usually caused by atherosclerosis of the coronary arteries (coronary artery disease). Those at greater risk include regular smokers, older individuals, patients with high blood cholesterol levels, diabetics, and people with hypertension (high blood pressure).
Written by Christian Nordqvist