Your Resting Heart Rate – What It Means

About ten years ago it became known that increased resting heart rate was associated with high blood pressure, raised cholesterol levels, raised blood sugar levels, an increased risk of heart rhythm disturbances, and atherosclerotic plaque.  In some studies, an increased resting heart rate was linked to increased mortality.  But there’s always been the question: can physical exercise reverse the risk of earlier death?  A Norwegian study reported in the Journal of Epidemiology & Community Health tackles this question.       

25,000 men and 25,000 women who were free from cardiovascular disease were enrolled between 1984 and 1986.  Data on general health and lifestyle were collected at baseline, along with self-estimated particulars of physical exercise taken.  Resting heart rates allowed the subjects to be classified into 5 groups or quintiles; this allowed an association between heart rate and death (in particular, ischemic cardiac death) to be established.

Analyses showed that, for each increase of 10 heart beats a minute at rest, the risk of death from ischemic heart disease was 18% higher in women under 70 years old.  In men, there was a 10% increased risk in the under 70s, and an 11% increased risk in the over 70s. 

The effect of self-reported physical activity on mortality was hard to assess.  Those who reported no physical activity were consistently at higher risk of cardiovascular disease than those who reported any level of activity.  In women, engaging in a high degree of physical activity the risk associated with a high resting heart rate was “substantially reduced”.  This was not the case in men, however; there was no clear indication that exercise could modify the detrimental effect of a high resting heart rate.  The researchers think this may be due to over-estimation of the degree of physical activity by a proportion of men in the study.         

As aerobic exercise is well-known to lower resting heart rate in athletes (and others), it seems to make sense for younger people with a high resting heart rate to take up physical exercise seriously.  If their heart rates are lowered by such activity, it can only be a good thing – and it may well result in reduced risk of premature death. . .