COMMENTARY

Title, Date of Publication & Journal

Elevated resting heart rate, physical fitness and all-cause mortality: a 16-year follow-up in the Copenhagen Male study, 15 April 2013, Heart.

Claim supported by evidence?

• The paper demonstrates an increased risk of mortality in later years amongst healthy males amongst those with a higher Resting heart Rate (RHR).
• This apparent risk factor is shown to be independent of physical fitness, leisure time physical activity and other major cardiovascular risk factors.
• In line with previous studies, smoking was more common amongst those with low RHR, and there was some suggestion that the risk from high RHR was greatest in those who smoked.
• There was no direct evidence that lowering your HRH improved life expectancy.

Summary

• Well controlled long term study carried out in a healthy worker population.
• Less than a half of those invited to take part in the original study in 1970-71 appear in the analysis. About 20% were non-responders at the second examination in 1985-86.
• All hazard ratios in Table 2 are comparison to the lowest RHR group (<50bpm), which is the most extreme 8% of the subjects studied. As a result the paper and especially the press release stresses increased mortality, while in fact this represents the reduced mortality in this extreme group with low RHR.

Study Conclusions

• Conclusions in paper are well supported and carefully presented.
• The press release is confusing in that it presents hazards ratios compared to the most extreme subgroup, and as a result stresses high mortality rates.

Strengths/Limitations

• Table 1 is confusing as the number of subjects’ column (n) is misaligned. See table 2 instead.