Study finds ultimate hack to protect teen brains from harmful screen time: Exercise (and good role-modeling)

Recent­ly, the Wall Street Jour­nal ran an arti­cle about how Insta­gram was affect­ing teen men­tal health. In par­tic­u­lar, some inter­nal stud­ies at Face­book (which owns Insta­gram) appeared to con­firm that when teen girls used the site, they suf­fered poor­er body image and were at increased risk for depres­sion and eat­ing disorders.

But is social media use itself at fault for mak­ing teen men­tal health worse? While some stud­ies sug­gest it is, oth­ers paint a more nuanced pic­ture, find­ing it dif­fi­cult to pin­point prob­lems with screen time itself ver­sus oth­er fac­tors some­times asso­ci­at­ed with social media use that may reduce teen well-being—like cyber­bul­ly­ing or social iso­la­tion. Plus, cur­rent con­clu­sions are often based on data from a sin­gle point in time, which makes it hard to prove that extend­ed screen time actu­al­ly caus­es poor­er men­tal health.

Now, find­ings from an inter­na­tion­al study on teens (details below) add more to this debate and point toward poten­tial guide­lines for screen use. Focus­ing on over 577,000 ado­les­cents from 42 coun­tries across Europe and North Amer­i­ca, the study’s results sug­gest that we might not have to wor­ry about screen time in small­er dos­es, until it reach­es a cer­tain harm­ful lev­el, and that exer­cise can play a pro­tec­tive role no mat­ter how much time a teen spends on screens.

For the study, researchers used large-scale sur­veys four years apart (in 2006, 2010, and 2014). Teens between 11 and 15 years old report­ed on how much of their free time they spent reg­u­lar­ly on screens, watch­ing TV or YouTube videos, gam­ing, check­ing social media, chat­ting or email­ing with friends, and surf­ing the inter­net. They also report­ed how many days a week they exer­cised, how sat­is­fied they were with their lives, and about their men­tal health, not­ing how fre­quent­ly they felt emo­tion­al­ly down, irri­ta­ble, angry, or ner­vous, and how often they had dif­fi­cul­ties falling asleep, dizzi­ness, headaches, stom­achaches, and back­ach­es (phys­i­cal symp­toms asso­ci­at­ed with poor men­tal health).

Analy­ses showed that low­er amounts of screen time had no effect on teen well-being. Girls who spent less than an hour on screens and boys who spent less than 90 min­utes on screens were not neg­a­tive­ly impact­ed by it. But at high­er amounts of screen time, their life sat­is­fac­tion dropped significantly—they were less hap­py with their lives, and it got worse the more time they spent. If screen time went above 105 min­utes per day for boys or 75 min­utes per day for girls, their men­tal health also got worse.

Accord­ing to the lead author, Asaduz­za­man Khan of the Uni­ver­si­ty of Queens­land, Aus­tralia, these find­ings sup­port the ear­li­er guide­lines issued by the Amer­i­can Pedi­atric Soci­ety, which sug­gests that teens not spend more than two hours on screens per day.

If screen time goes beyond about two hours per day, there’s a detri­men­tal rela­tion­ship with men­tal health,” he says.

On the oth­er hand, he adds, his study also found that teens who got more reg­u­lar exer­cise had greater life sat­is­fac­tion and few­er phys­i­cal com­plaints for both gen­ders. Not only that, the effects were large­ly unre­lat­ed to how much time a teen spent on screens, so that if teens exer­cised more, it could poten­tial­ly undo the dam­age to their well-being that went along with even six or eight hours of screen time.

Khan says that this sug­gests a two-pronged approach to improv­ing teen well-being.

If we want to improve kids’ men­tal health, we need to tar­get both behaviors—to min­i­mize screen time and max­i­mize phys­i­cal activ­i­ty,” says Khan. “If we are tar­get­ing just one behav­ior, then it might be a missed opportunity.”

In the study, the great­est life sat­is­fac­tion was report­ed by boys who had one to two hours of screen time a day and were active sev­en days per week, while girls who exer­cised every day and had less than an hour of screen time fared best—in line with Khan’s sug­gest­ed fix.

But Khan warns par­ents and oth­ers not to be over­ly con­cerned by his results…yet. There are lim­i­ta­tions to the study, includ­ing uncer­tain­ty about the effects of dif­fer­ent types of screen time on men­tal well-being. For exam­ple, it may be that scrolling through social media has a very dif­fer­ent impact on well-being than play­ing video games, or that girls do bet­ter with one type of dig­i­tal enter­tain­ment than boys. Some of his more cur­rent research (not yet pub­lished) sup­ports this idea, he says, though clear­ly much more needs to be done before we can know all of the nuances of this.

Still, it does sug­gest that par­ents might want to encour­age their teens to lessen screen time in favor of more exer­cise if they can. He sug­gests par­ents con­sid­er employ­ing online tools that can alert teens (or any­one) when they’ve reached a rea­son­able lim­it on their screen time—such as after they’ve watched an hour of YouTube videos. Or it’s a good idea, he says, to take planned breaks from all screens from time to time—a sort of “dig­i­tal detox.”

While it makes sense to pro­mote this idea to teens, it may be eas­i­er said than done to change a teen’s use of dig­i­tal media—especially now, when COVID-19 has forced many teens online more than ever. Khan also notes that it’s hard to impose restric­tions on teens unless par­ents are role-mod­el­ing good behav­ior themselves.

If I’m watch­ing Net­flix for five hours, it’s non­sense to assume that my teen is going to go out­side and do activ­i­ties there,” he says. “Par­ents and kids need to work togeth­er on this and fig­ure out how to replace some of their screen time with ‘green time.’”

Schools can also help improve ado­les­cent well-being, he says. Too often, schools rely heav­i­ly on dig­i­tal tools to teach or com­mu­ni­cate with stu­dents, while not pro­vid­ing enough access to out­door phys­i­cal activ­i­ties. Pro­grams that encour­age more exercise—like orga­niz­ing bike rid­ing com­mutes to school—could be a plus.

In the mean­time, he and his col­leagues hope to pub­lish their next study, which may help pro­vide more fine­ly tuned rec­om­men­da­tions on screen time, help­ing pedi­a­tri­cians and par­ents alike to make smart choic­es around children’s well-being.

We are very close to the time when we can make more pre­cise guide­lines that con­sid­er not only how over­all time on screens impacts men­tal health, but how expo­sure to dif­fer­ent types of screens affects it in dif­fer­ent ways,” he says. ”That will help prac­ti­tion­ers, par­ents, and kids under­stand what lim­its to set.”

— Jill Sut­tie, Psy.D., is Greater Good‘s book review edi­tor and a fre­quent con­trib­u­tor to the mag­a­zine. Based at UC-Berke­ley, Greater Good high­lights ground break­ing sci­en­tif­ic research into the roots of com­pas­sion and altru­ism. Copy­right Greater Good.

The Study:

Dose-depen­dent and joint asso­ci­a­tions between screen time, phys­i­cal activ­i­ty, and men­tal well­be­ing in ado­les­cents: an inter­na­tion­al obser­va­tion­al study (The Lancet Child and Ado­les­cent Health). From the Abstract:

  • Back­ground: Men­tal well­be­ing in ado­les­cents has declined con­sid­er­ably dur­ing past decades, mak­ing the iden­ti­fi­ca­tion of mod­i­fi­able risk fac­tors impor­tant. Pro­longed screen time and insuf­fi­cient phys­i­cal activ­i­ty appear to oper­ate inde­pen­dent­ly and syn­er­gis­ti­cal­ly to increase the risk of poor men­tal well­be­ing in school-aged chil­dren. We aimed to exam­ine the gen­der-strat­i­fied dose-depen­dent and joint asso­ci­a­tions of screen time and phys­i­cal activ­i­ty with men­tal well­be­ing in adolescents.
  • Meth­ods: We used data from three rounds of Health Behav­iour in School-aged Chil­dren cross-sec­tion­al sur­veys (2006, 2010, and 2014) from 42 Euro­pean and North Amer­i­can coun­tries. Sur­vey par­tic­i­pants, aged 11 years, 13 years, and 15 years, pro­vid­ed self-report­ed infor­ma­tion by com­plet­ing an anony­mous ques­tion­naire that includ­ed items on health indi­ca­tors and relat­ed behaviours…
  • Find­ings: Our sam­ple includ­ed 577?475 ado­les­cents … Detri­men­tal asso­ci­a­tions between screen time and men­tal well­be­ing start­ed when screen time exceed­ed 1 h per day, where­as increas­es in phys­i­cal activ­i­ty lev­els were ben­e­fi­cial­ly and monot­o­n­i­cal­ly asso­ci­at­ed with well­be­ing. Mul­ti­level mod­el­ling showed that screen time lev­els were neg­a­tive­ly asso­ci­at­ed with life sat­is­fac­tion and pos­i­tive­ly asso­ci­at­ed with psy­cho­so­mat­ic com­plaints in a dose-depen­dent man­ner. Phys­i­cal activ­i­ty lev­els were pos­i­tive­ly asso­ci­at­ed with life sat­is­fac­tion and neg­a­tive­ly asso­ci­at­ed with psy­cho­so­mat­ic com­plaints in a dose-depen­dent manner…
  • Inter­pre­ta­tion: High­er lev­els of screen time and low­er lev­els of phys­i­cal activ­i­ty were asso­ci­at­ed with low­er life sat­is­fac­tion and high­er psy­cho­so­mat­ic com­plaints among ado­les­cents from high-income coun­tries. Pub­lic health strate­gies to pro­mote ado­les­cents’ men­tal well­be­ing should aim to decrease screen time and increase phys­i­cal activ­i­ty simultaneously.

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About SharpBrains

SHARPBRAINS is an independent think-tank and consulting firm providing services at the frontier of applied neuroscience, health, leadership and innovation.
SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

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