Adolescent girls and young women are less likely to engage in heart-rate raising recreational activities than their male peers – and when they do, keep at it for shorter periods of time, new research has revealed.
Current guidelines recommend that children and teens undertake at least an hour of moderate or vigorous physical activity a day, with adults advised to aim for 150 minutes a week.
However, a study from the US has found that more than 20 per cent of adolescent girls and 12 per cent of boys do no sports or recreational physical activity in a week, with just under 30 per cent of men and almost 40 per cent of women, aged 18-29, saying the same.
In Ireland, a major study released earlier this year indicated there was a "startling drop-off" in fitness among secondary school students after the Junior Cert, with a majority of PE teachers surveyed saying students have less interest in physical activity in exam years, while similar numbers believe parents are not interested in how their children progress in this area.
Previous research has shown that Irish 15- to 16-year-olds already show signs of heart disease due to poor fitness, while boys with low levels of fitness had significantly more plaque in the walls of the arteries supplying the brain than very fit boys.
Dr Charlene Wong from Duke University in North Carolina, co-author of the American study, said the research could help to direct public health interventions, noting the study suggests the focus should be on females, young adults and those from minority and low-income backgrounds.
“Our black female young adults were the least likely to say they did any physical activity and those who did were active for the shortest amount of time,” she said.
Writing in the journal Jama Pediatrics, Wong and colleagues describe how they pooled and analysed data from an annual nationwide health survey in the US, encompassing the years 2007 to 2016, focusing on responses from 9,472 individuals aged between 12 and 29.
Levels of physical activity
The survey, carried out through interviews, asked participants questions about their levels of physical activity relating to sports or recreational pursuits.
While almost 88 per cent of boys aged between 12 and 17 reported some moderate or vigorous exercise in a week, the figure fell to just under 73 per cent for males aged 18 to 24, and to just below 71 per cent for those aged 25 to 29. For females the proportion fell from just over 78 per cent of adolescents to just over 61 per cent for both of the older age groups.
For those who did get their blood pumping, the amount of time spent exercising also fell with age, from just over 71 minutes a day for adolescent boys to just over 50 minutes for those aged 25 to 29. For girls, it fell from 56 minutes to just over 39 minutes a day respectively.
White adolescent boys were the most likely to say they exercised in a week, with black males aged 18-24 reporting the longest duration of physical activity a day.
Once factors including weight, education and income were taken into account, the team found race was linked to whether females reported any physical activity: in general, a larger proportion of white females said they exercised than black or Hispanic participants. The trend was less clear for males.
Higher income was linked to reporting physical activity for females regardless of age, but the same only held true for adolescent boys and not young men, while young adults with a college education were more likely to report any exercise across both sexes. Weight had little impact on whether participants reported exercising.
While it is not clear what is behind the trends, the authors say multiple factors might be at play, including issues around body image, social norms for exercise being different between the sexes, less scheduled activity after leaving school and growing pressures of working life.
But the study had limitations, including that activity such as walking to work was not included, it was not considered whether participants had children, or were pregnant, and the authors admit that self-reported data can lead to an over-estimation of activity.
