New Zealand teenagers are less fit and weigh more than their parents were at the same age, new University of Otago research reveals.
A comparison of 15-year-olds across two generations - believed to be the first study to directly compare the physical fitness of two generations of 15-year-old New Zealanders - has found there has been a decline in adolescent physical fitness.
The decline in fitness between generations has been accompanied by an increase in body weight, in keeping with global trends of increasing body weight among children and young people.
Fitness was measured on an exercise cycle among members of the Dunedin Multidisciplinary Health and Development Study when they were aged 15 in 1986/1987. The same fitness test was done on 343 of their 15-year-old children between 2007 and 2015.
The decline in fitness was particularly noticeable for girls who weighed more and were less fit than their mothers had been at the same age. The decline in fitness among boys was smaller, but they were also less fit than their fathers had been at age 15, once body weight was taken into account.
One of the researchers Dr Helena McAnally says that while both girls and boys were less fit than their parents had been, the change was particularly noticeable for girls whose fitness test scores were about 25 per cent lower than their mother's generation.
"It is well recognised that girls become less physically active earlier in adolescence, and this may be why their fitness levels were so much lower," Dr McAnally says.
"We know fitness in adolescent tracks into adulthood and so these changes may have important long-term consequences for health and well-being."
The research was led by Professor Bob Hancox who explains that while trends of increasing levels of overweight and obesity among young people are well recognised, there has been little research on changes in fitness.
"Our study is unusual in that we have measured fitness using the same technique in two generations of New Zealanders. The findings support many people's perception that young people are less active and fit than their previous generations," Professor Hancox says.
The study measured fitness using a cycle test. The cycle test measure used is less likely to be influenced by changes in body weight than running tests because it does not require you to carry your weight while exercising. Therefore, findings of reduced fitness in this research are not likely to be explained by increases in body weight.
The research was funded by the Health Research Council of New Zealand and supported by the Department of Preventive and Social Medicine. It was published today in the New Zealand Medical Journal.
For further information, contact:
Dr Helena McAnally
Mob 021 0269 2723
Senior Communications Adviser
Tel 03 479 9065
Mob 021 279 9065
Notes for editors:
The Dunedin Multidisciplinary Health and Development Study
The Dunedin Multidisciplinary Health and Development Study (Dunedin Study) is an ongoing, longitudinal study of the health, development and well-being of a general sample of New Zealanders. They were studied at birth (1972-1973), followed up and assessed at the age of three when the longitudinal study was established. Since then they have been assessed every two years until the age of 15, then at ages 18, 26, 32 and 38. The study members are currently being assessed at age 45 (2017-2019) and it is hoped to continue further assessments in the future.
Sub-studies of the Dunedin Study
The Family Health History Study (2003-2006)
The Family Health History Study began in 2003 and finished in January 2006, with more than 1900 interviews completed and over 90 per cent of Dunedin Multidisciplinary Health and Development Study members' parents (and some aunts and uncles) being interviewed. The purpose of this study was to find out about the health of the families of the Dunedin Study members.
The Parenting Study
This study focuses on members of the Dunedin Study and their first-born 3-year-old children. The aim is to identify the social and family determinants of parenting style, and to study continuities and discontinuities in parenting from the parenting experienced by the Study members themselves.
The Next Generation Study
The purpose of the Next Generation Study is to look at the lifestyles, behaviours, attitudes and health of today's teenagers, and see how they have changed from when our original Dunedin Study members were 15 in 1987-1988.