Screen Time & Young Hearts: A Look at a Recent Sydney Study

This post is by regular contributor Naomi Cook.

We are not ‘T.V people.’ However, my three year old enjoys an educational DVD whilst I make dinner and she also enjoys educational apps on my iPhone. I have seen tremendous learning outcomes from both of these forms of screen time. I frequently find these forms of entertainment a lifesaver, blissful relief from incessant ‘why’ questions and demands for yet another outfit change at the end of a busy day. Sometimes I feel guilty for feeling that relief… I am aware that this ‘tech-savvy toddler’ generation is a new phenomenon. I often wonder how much screen time she should have at this tender age. How much is too much? How much could be considered beneficial?

The Sydney Study 1

A recent study has shown that children who spend hours watching television every day are prone to developing narrowed arteries in the eyes. According to researchers in Sydney, this may signify an increased chance of developing cardiovascular disease in the future. 3

The study looked at over 1700 children, aged six. Some children were active and sporty, the others were more sedentary and had more screen time. The children that were more active had wider arteries in their retina than the less active children who had more screen time. 1

  • You may be wondering what the size of blood vessels in the retina has to do with evaluating the risk of cardiovascular disease! However, narrowed blood vessels in the retina are commonly used as markers for high blood pressure and heart disease. 2,3,4
  • According to the researchers the “magnitude” of each hour of screen time per day can be compared to a 10mmHg increase in systolic blood pressure. 1 For example; a blood pressure increase of 120/80 to 130/80. Children spent an average of 1.9 hours with screen time and an average of 36 minutes in outdoor play. 3, 4 Those who spent more than an hour playing outdoors daily had wider retinal arteries than those spending less. 4
  • The authors claim that the issue is not the screen time itself that is the problem, rather the time spent being sedentary. 2 However as we know, the more the screen time, the greater the inactivity.
  • One of the authors of the study has been quoted saying that over 1.5 hours of screen time a day was enough to see adverse effects on the blood vessels. 4

As a direct consequence of reading this article I became even stricter with monitoring my daughters screen time; sixty minutes is our daily limit.

Since this is the first study of its kind we can look forward to further research in this area. Hopefully future studies will look at things such as whether or not the microvascular changes are reversible over time with increased levels of activity. I also hope that future studies will continue to separate out types of sedentary activity, for example reading and puzzles versus ‘screen time’ in addition to active indoor as opposed to active outdoor play.

How do you manage your children’s screen time? How much do you think is too much?

References

  1. Gopinath B, Baur L, Wang J, Hardy L, Teber E, Kifley A, Wong T and Mitchell P (2011) Clinical and Population Studies: Influence of Physical Activity and Screen Time on the Retinal Microvasculature in Young Children Arteriosclerosis, Thrombosis and Vascular Biology 2011, 31:1233-39
  2. CTVNews
  3. MedicineNet
  4. Medline Plus

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13 Comments

  1. This is very interesting, but I have issues with the cause of the arteries shrinking due to being sedentary. Reading is also a sedentary activity. Should we tell our children they’re not allowed to read more than an hour a day? Also, if being still is what is causing these problems, then there’s also going to have be a major overhaul of the school systems that insist on children sitting in their seats for the better part of seven hours a day. I’m guessing that there’s something a bit more to the connection between the shrinking retinal arteries and the t.v. than just being sedentary.

  2. We are not big TV watchers in our house either. We do use the TV as a ‘tool’ for all of us, a way to relax on the odd occasion, and we all enjoy using computers and other screen toys from time to time.
    This is such an interesting discussion….but the problem I have with research findings like these is that they isolate one aspect of life and that feels so ‘unreal’ to me that I have trouble attributing much worth to their findings.
    Did the study look at children who perhaps used a screen for 1.5 hours a day but who spent lots of other time being very active? Or as Talia said, what about children who never watched a screen but who were inactive doing other things?
    It seems to me that it is not screen time that is the problem but inactivity, so I think I’d rather concentrate on getting myself and my kids outside and doing something rather than worrying about how long that sit in front of a screen….
    I have plenty of other reasons to dislike lots of screen time LOL

    1. Naomi Cook says:

      Great! I’m always open to input from readers on issues/topics they would like explored and discussed, so please keep in touch!

  3. Naomi Cook says:

    I agree, it’s worth saying that the researchers themselves were very cautious in how they presented their findings by saying that there “could” be a link. As with all singled out studies, it must be taken quite lightly until there is more to corroborate the preliminary findings.

    Ultimately though, I really don’t think it tells us much more than we already know! We already know that it’s good for kids to be active and run around, we already know that most kids are too ‘sedentary’ as childhood obesity is a growing problem. As kate says, there are so many other issues associated with screen time, from a tendency to unhealthy eating habits whilst watching and also the negative influences of inappropriate programs and advertising. Haven’t got the name to hand but there have been separate studies on screen time and vision/eyes that aren’t linked to cardiovascular issues.

  4. I think it comes down to whether you want to teach your child to squelch boredom or learn to keep themselves occupied with the t.v. or to teach them to become in to the habit of entertaining themselves with more creative and productive activities. Creative activities offer more problem-solving and deeper thinking than even the most educational mostly entertaining shows. The values of what each family holds dearest is different for each family. This is one area where each family can make a choice to increase creativity and a child’s self-reliance on their own self-occupation if they choose to limit t.v. time.

  5. I’d be interested to see this study! The correlation between screen time and artery shrinkage does not imply that one caused the other.

    Still, it’s a compelling reason to limit tv!

    1. Naomi Cook says:

      Hi Joanna,
      I have a reply pending with a couple of links…

      I hear where you’re coming from but we should remember that this is just a study of correlation (not of direct casual linkage), and the issue at stake is the strength of the correlation which is demonstrated through statistical analysis.

  6. Studies like these are important. It’s unlikely that we are going to get families to turn off the tube all the time, but setting a general limit on time spent watching TV gives parents parameters.
    If a child is only reading at the cost exercising , then the child needs to be encouraged to play actively too. There is such a thing as too much of a good thing.
    The important thing here is that kids need to have a variety of activities that encourage social, intellectual, and physical development.

    1. Naomi Cook says:

      Great point…one thing that alot of the media were claiming in relation to this study was that parents have to be the model!

  7. Loved the article Naomi!I also found this article very interesting! There are so many factors and dynamics to a family’s lifestyle and although these articles can be informative and make us stop and think to re-evaluate children’s screentime activities they also have the potential to make many parents feel inadequate and guilty if they allow there child any screentime at all.We all want our children to be healthy and active and to get outdoors ,but the reality of being able to do this on a daily basis is quite a challenge!
    I think the problem is with kids watching lots of bad tv. Educational stuff like PlaySchool is amazing and inspirational.

    1. Naomi Cook says:

      Thanks for that Jade…I’m a huge fan of playschool. I agree it is hard in reality to get kids outside for lengthy periods, just how I would manage outside of Australia in a cold rainy country is beyond me!

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