̽��ֱ�� of Cambridge - Kirsten Corder

Becoming less active and gaining weight: downsides of becoming an adult

cjb250 — Mon, 20 Jan 2020 00:15:23 +0000

Many people tend to put on weight as they leave adolescence and move into adulthood, and this is the age when the levels of obesity increase the fastest. This weight gain is related to changes in diet and physical activity behaviour across the life events of early adulthood, including the move from school to further education and employment, starting new relationships and having children.

Writing in Obesity Reviews, researchers from the Centre for Diet and Activity Research (CEDAR) at Cambridge looked at changes in physical activity, diet and body weight as young adults move from education into employment and to becoming a parent. To do this, they carried out systematic reviews and meta-analyses of existing scientific literature – these approaches allow them to compare and consolidate results from a number of often-contradictory studies to reach more robust conclusions.

Leaving school

In the first of the two studies, the team looked at the evidence relating to the transition from high school into higher education or employment and how this affects body weight, diet and physical activity. In total, they found 19 studies covering ages 15-35 years, of which 17 assessed changes in physical activity, three body weight, and five diet or eating behaviours.

̽��ֱ��team found that leaving high school was associated with a decrease of seven minutes per day of moderate-to-vigorous physical activity. ̽��ֱ��decrease was larger for males than it was for females (a decrease of 16.4 minutes per day for men compared to 6.7 minutes per day for women). More detailed analysis revealed that the change is largest when people go to university, with overall levels of moderate-to-vigorous physical activity falling by 11.4 minutes per day.

Three studies reported increases in body weight on leaving high school, though there were not enough studies to provide a mean weight increase. Two studies suggested that diets decrease in quality on leaving high school and one suggested the same on leaving university.

“Children have a relatively protected environment, with healthy food and exercise encouraged within schools, but this evidence suggests that the pressures of university, employment and childcare drive changes in behaviour which are likely to be bad for long-term health,” said Dr Eleanor Winpenny from CEDAR and the MRC Epidemiology Unit at the ̽��ֱ�� of Cambridge.

“This is a really important time when people are forming healthy or unhealthy habits that will continue through adult life. If we can pinpoint the factors in our adult lives which are driving unhealthy behaviours, we can then work to change them.”

Becoming a parent

In the second study, the team looked at the impact of becoming a parent on weight, diet and physical activity.

A meta-analysis of six studies found the difference in change in body mass index (BMI) between remaining without children and becoming a parent was 17%: a woman of average height (164cm) who had no children gained around 7.5kg over five to six years, while a mother of the same height would gain an additional 1.3kg. These equate to increases in BMI of 2.8 versus 3.3.

Only one study looked at the impact of becoming a father and found no difference in change.

There was little evidence looking at physical activity and diet. Most studies including physical activity showed a greater decline in parents versus non-parents. ̽��ֱ��team found limited evidence for diet, which did not seem to differ between parents and non-parents.

“BMI increases for women over young adulthood, particularly among those becoming a mother. However, new parents could also be particularly willing to change their behaviour as it may also positively influence their children, rather than solely improve their own health,” said Dr Kirsten Corder, also from CEDAR and the MRC Epidemiology Unit.

“Interventions aimed at increasing parents’ activity levels and improving diet could have benefits all round. We need to take a look at the messages given to new parents by health practitioners as previous studies have suggested widespread confusion among new mothers about acceptable pregnancy-related weight gain.”

Reference
Winpenny, E. et al. Changes in physical activity, diet and body weight across the education and employment transitions of early adulthood: A systematic review and meta-analysis. Obesity Reviews; 20 Jan 2020

Corder, K. et al. Becoming a parent: a systematic review and meta-analysis of changes in BMI, diet and physical activity. Obesity Reviews; 20 Jan 2020

Leaving school and getting a job both lead to a drop in the amount of physical activity, while becoming a mother is linked to increased weight gain, conclude two reviews published today and led by researchers at the ̽��ֱ�� of Cambridge.

Children have a relatively protected environment, with healthy food and exercise encouraged within schools, but this evidence suggests that the pressures of university, employment and childcare drive changes in behaviour which are likely to be bad for long-term health

Eleanor Winpenny

Anupam Mahapatra

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Use of TV, internet and computer games associated with poorer GCSE grades

cjb250 — Fri, 04 Sep 2015 07:00:21 +0000

In a study published today in the open access International Journal of Behavioral Nutrition and Physical Activity, researchers also found that pupils doing an extra hour of daily homework and reading performed significantly better than their peers. However, the level of physical activity had no effect on academic performance.

̽��ֱ��link between physical activity and health is well established, but its link with academic achievement is not yet well understood. Similarly, although greater levels of sedentary behaviour – for example, watching TV or reading – have been linked to poorer physical health, the connection to academic achievement is also unclear.

To look at the relationship between physical activity, sedentary behaviours and academic achievement, a team of researchers led by the Medical Research Council (MRC) Epidemiology Unit at the ̽��ֱ�� of Cambridge studied 845 pupils from secondary schools in Cambridgeshire and Suffolk, measuring levels of activity and sedentary behaviour at age 14.5 years and then comparing this to their performance in their GCSEs the following year. This data was from the ROOTS study, a large longitudinal study assessing health and wellbeing during adolescence led by Professor Ian Goodyer at the Developmental Psychiatry Section, Department of Psychiatry, ̽��ֱ�� of Cambridge.

̽��ֱ��researchers measured objective levels of activity and time spent sitting, through a combination of heart rate and movement sensing. Additionally the researchers used self-reported measures to assess screen time (the time spent watching TV, using the internet and playing computer games) and time spent doing homework, and reading for pleasure.

̽��ֱ��team found that screen time was associated with total GCSE points achieved. Each additional hour per day of time spent in front of the TV or online at age 14.5 years was associated with 9.3 fewer GCSE points at age 16 years – the equivalent to two grades in one subject (for example from a B to a D) or one grade in each of two subjects, for example. Two extra hours was associated with 18 fewer points at GCSE.

Screen time and time spent reading or doing homework were independently associated with academic performance, suggesting that even if participants do a lot of reading and homework, watching TV or online activity still damages their academic performance.

̽��ֱ��researchers found no significant association between moderate to vigorous physical activity and academic performance, though this contradicts a recent study which found a beneficial effect in some academic subjects. However, both studies conclude that engaging in physical activity does not damage a pupil’s academic performance. Given the wider health and social benefits of overall physical activity, the researchers argue that it remains a public health priority both in and out of school.

As well as looking at total screen time, the researchers analysed time spent in different screen activities. Although watching TV, playing computer games or being online were all associated with poorer grades, TV viewing was found to be the most detrimental.

As this was a prospective study – in other words, the researchers followed the pupils over time to determine how different behaviours affected their academic achievement – the researchers believe they can, with some caution, infer that increased screen time led to poorer academic performance.

“Spending more time in front of a screen appears to be linked to a poorer performance at GCSE,” says first author Dr Kirsten Corder from the Centre for Diet and Activity Research (CEDAR) in the MRC Epidemiology Unit at the ̽��ֱ�� of Cambridge. “We only measured this behaviour in Year 10, but this is likely to be a reliable snapshot of participants’ usual behaviour, so we can reasonably suggest that screen time may be damaging to a teenager’s grades. Further research is needed to confirm this effect conclusively, but parents who are concerned about their child’s GCSE grade might consider limiting his or her screen time.”

Unsurprisingly, the researchers found that teenagers who spent their sedentary time doing homework or reading scored better at GCSE: pupils doing an extra hour of daily homework and reading achieved on average 23.1 more GCSE points than their peers. However, pupils doing over four hours of reading or homework a day performed less well than their peers – the number of pupils in this category was relatively low (only 52 participants) and may include participants who are struggling at school, and therefore do a lot of homework but unfortunately perform badly in exams.

Dr Esther van Sluijs, also from CEDAR, adds: “We believe that programmes aimed at reducing screen time could have important benefits for teenagers’ exam grades, as well as their health. It is also encouraging that our results show that greater physical activity does not negatively affect exam results. As physical activity has many other benefits, efforts to promote physical activity throughout the day should still be a public health priority.”

̽��ֱ��research was mainly supported by the MRC and the UK Clinical Research Collaboration.

Reference
Corder, K et al. Revising on the run or studying on the sofa: Prospective associations between physical activity, sedentary behaviour, and exam results in British adolescents. International Journal of Behavioral Nutrition and Physical Activity; 4 Sept 2015.

Each extra hour per day spent watching TV, using the internet or playing computer games during Year 10 is associated with poorer grades at GCSE at age 16, according to research from the ̽��ֱ�� of Cambridge.

Parents who are concerned about their child’s GCSE grade might consider limiting his or her screen time

Kirsten Corder

Al Ibrahim

365.060 - Watching TV

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Every hour you spend in front of a screen is linked to poorer exam results

Anonymous — Thu, 03 Sep 2015 23:10:20 +0000

By the time they are teenagers, more than two-thirds of young people are not doing enough physical activity. Teenagers spend an average of eight hours every day sitting, with 11 to 15-year-olds watching nearly three hours of television. Most of us are well aware that such behaviour risks damaging their physical health, but there’s an additional problem. I have been involved in a new piece of research which suggests that too much screen time is also harming grades.

We measured the physical activity and sitting time of 845 teenagers at 14.5 years old, using a sensor that measures movement and heart rate. We asked how much time they spent watching TV, playing computer games, going online, doing homework and reading. And at the end of year 11, when these students were 16-years-old, we collected their GCSE results.

We found that teenagers with higher screen time had lower GCSE grades, even when we took account of differences in homework and reading. Television, computer games and internet use were all associated with poorer academic performance, but TV viewing was the most detrimental. For every hour that someone watched per day, they showed a drop of nine GCSE points in total – the equivalent of two whole grades in one subject (or for example, one grade in each of two subjects). Two extra hours was associated with 18 fewer points.

Although we did not find that more physical activity was associated with higher grades, as some other studies have suggested, it was not detrimental to academic performance either. It’s important that this message isn’t lost among the findings about screen time: schools are under so much pressure to improve exam results that many don’t prioritise PE and other opportunities for physical activity for fear that they interfere with academic achievement.

̽��ֱ��case for 60 a day

̽��ֱ��wider picture is that most teenagers are failing to meet the recommendations of doing at least 60 minutes of moderate or vigorous physical activity each day (activity that makes you sweat and breathe heavily). This needs to change if we are to develop a more rounded approach to our children’s education. Behaviours developed in the teenage years are likely to persist into adulthood, and we need to take every opportunity to improve the nation’s health by tackling high levels of physical inactivity across the population.

There are many reasons for young people not taking enough exercise, which will differ for each individual. Teenagers are often given a bad press about being lazy but I don’t believe that, and we should resist the temptation to blame them. Even as someone who studies and promotes physical activity, for example, I find it hard to fit it into my day, and it certainly wasn’t a priority for me at school.

In our research, we asked teenagers how we could help them to be more active and sit less. ̽��ֱ��overwhelming response was that they didn’t want to be sitting around, but lacked opportunities to be active in a way that interested them. They wanted more variety and choice about what activities they tried, telling us that the limited range of school sports was putting most of them off. This dislike of PE in high school could sour exercise for life. Offering a range of non-traditional activities – from martial arts to zumba – over the usual football or netball could encourage young people to take more exercise.

A related point is that while many strategies have focused on educating us about the health benefits of exercise, it looks like that doesn’t work. We need to change the way we pitch the message instead. Researchers and practitioners need to find out what motivates people and use that to convince them to be active instead. For instance one fascinating study paired adult men with Scottish football clubs for a weight loss and healthy-living intervention. ̽��ֱ��programme succeeded in encouraging this hard-to-reach group to improve their health because it tapped into these men being fans of football rather than health benefits.

Not fine to recline. Jeff Wasserman

Be lean with screens

Put this all together and a win/win answer begins to emerge. So long as homework and reading time are protected, schools and parents should be looking to encourage teenagers to swap screen time for physical activity. And in a multi-screen world that teenagers navigate frequently without supervision, we will need to become more sophisticated about how we guide the amount of time they spend in front of screens and what choices they make instead. Encouraging a good variety of physical activity and tapping into what makes them tick rather than speaking endlessly about health benefits looks like a good place to start. Achieve this goal and it looks like the way to maximise academic achievement and reduce health risks at the same time.

We also need to think about what happens in future. Screens are proliferating and we’re not going to get rid of them. Nor should we want to – the worlds that young people can access through screens can educate, inform and enrich their lives, from nature documentaries to Minecraft. And with more and more activities moving online – including educational resources – there are many unanswered questions about how future generations may adapt. For now and the future, the challenge is to get teenagers more active so that once they’ve done their homework, the last thing that they think of is sitting in front of a screen.

Kirsten Corder is Senior Investigator Scientist at ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

We need to think about how our teenagers spend their spare time, writes Dr Kirsten Corder from the Medical Research Council Epidemiology Unit at the ̽��ֱ�� of Cambridge, whose research has shown that even an hour a day of TV and internet use is linked to poorer GCSE grades.

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