14 November 2013

Resting Pulse Rates of UK Pre-teens Have Risen During Past 30 Years

The resting pulse rate of UK pre-teens is estimated to have risen by up to two beats a minute during the past 30 years, but the rise does not seem to be linked to the overall weight gain seen in this age group, according to a Medical Research Council funded study, published in theArchives of Disease in Childhood.

While this rise may seem modest, resting pulse rate is a predictor for general physical fitness and cardiovascular health, say the authors, and it could translate into higher risks of diabetes and heart disease in later life.

The findings were based on serial resting pulse rate measurements of almost 23,000 UK children between the ages of 9 and 11, who were part of five studies/surveys between 1980 and 2008. These included the 1970 British birth cohort; the Brompton cohort; the Two Towns Study; the Ten Towns Study; and the annual Health Survey for England (1995-8, 2002, 2006-8).

Overall, average pulse rate was higher in girls at 82.2 beats per minute (bpm) than in boys (78.7 bpm). However, the pulse rate rose consistently over the 30-year period for both sexes by an average of 0.04 bpm every year. The rise was steeper among boys (0.07 bpm), particularly after the mid 1990s, than among girls (0.03 bpm), equating to an increase of 2 bpm among boys and 1 bpm among girls.

During the 30-year tracking period, the average weight of this age group rose. While pulse rate is associated with body mass index (BMI), the rapid increase in BMI did not fully explain the increased resting pulse rate, possibly because BMI is not a very sensitive measure of lean and fat body mass, say the authors.

They suggest that a fall in the amount of physical activity taken by this age group and an increase in sedentary activity, may have contributed to the rise, as both of these are associated with poorer physical fitness.

While more research is needed to better explain the findings, the trends could have important public health repercussions, warn the authors. They said:

“Although modest, it is important to monitor these trends, especially in boys as they appear to have increased at a faster rate in recent years. If an increase of 2 bpm in mean resting pulse rate in boys persists to the adult population, this could result in a 4 per cent increase in coronary heart disease mortality among healthy men and a 2 per cent increase in risk of developing diabetes among the over 65s.”

The study was led by Dr Leah Li from the MRC Centre of Epidemiology for Child Health, at UCL.

Further information

The paper, entitled ‘Trends in resting pulse rates in 9–11-year-old children in the UK 1980–2008’, is published in the journal Archives of Disease in Childhood.