Less Scrolling, More Movement

Why we are starting here

Every product has a sentence underneath it that explains why it exists. Ours is four words long and it is printed on the first screen anybody sees: less scrolling, more movement.

This piece is the argument behind those words, written by both of us, because neither half works alone. One of us can tell you what the evidence says about sedentary behaviour and mortality. The other can tell you what it is like to be sixteen and find your only company inside a screen.

We are not going to pretend this is simple. The easy version of this argument says screens are bad and moving is good, and that version is wrong in ways the research is quite clear about. The honest version is more interesting and more useful.

So this is the long piece. It is the founding document of the Rep Room, and we would rather it be true than tidy.

The first thing everybody gets wrong about screens

Dr. Flavia P.

Before we talk about harm, we need to fix a measurement problem that runs through most of the public conversation.

Screen time is frequently used as a proxy for sedentary behaviour in physical activity and public health research. That assumption is largely inherited from television, which was watched from a sofa. Smartphones are portable, so screen time can now occur across a wide range of physical contexts.

A study tested this directly. Smartphone screen time was objectively measured using a passive sensing app, and movement was measured with wrist-worn accelerometers. The two data streams were aligned at five-second epochs across waking wear time, and the accelerometer data was processed to classify each epoch as sedentary or not.

Five-second resolution. Not a questionnaire asking people to estimate their week.

The primary outcome was the proportion of smartphone screen use occurring during sedentary versus non-sedentary behaviour, with secondary analysis of inactive versus active behaviour during the non-sedentary screen use.

The title states the finding: not all screen time is sedentary.

This matters enormously for how we talk to you. If someone tells you that your six hours of screen time equals six hours of sitting, they are using a proxy that has now been tested and found imprecise. Some of that time is spent walking, standing, moving between places.

That is the first piece of honesty. The enemy is not the screen itself. It is what the screen most often replaces.

This was an opportunistic analysis within an ongoing cohort of adult caregivers of preschool children, using Android devices. It is a specific population and a specific measurement method, and it establishes that the proxy is unreliable rather than quantifying by how much for everyone.

What sitting still actually costs

Dr. Flavia P.

Now the part that is not ambiguous.

A two-cohort study examined 122,966 older adults from the China Kadoorie Biobank and 207,212 from the UK Biobank. That is over three hundred and thirty thousand people across two continents and two very different health systems.

Sedentary behaviour and physical activity were assessed at baseline, with activity classified as light, moderate or vigorous by metabolic equivalents. The analysis used Cox proportional hazards models and isotemporal substitution models, which is the technique that lets you ask what happens if you swap one behaviour for another rather than simply adding activity on top.

Longer sedentary behaviour, per 30 minutes a day, was associated with higher all-cause mortality in both cohorts. In the Chinese cohort the hazard ratio was 1.013, with a confidence interval from 1.010 to 1.017. In the UK cohort, 1.012, interval 1.009 to 1.015.

Two independent cohorts, on opposite sides of the world, producing figures that agree to the third decimal place.

Those numbers look small because they are per 30 minutes. The exposure is not 30 minutes; it is every day of your life. And physical activity of any intensity was associated with reduced mortality risk, with replacing 30 minutes a day of sedentary time showing comparable protective associations across intensities in the Chinese cohort.

Any intensity. That is the part we want you to hold onto, and we will come back to it.

These are observational cohort studies. They establish association, not causation, and both used baseline questionnaires for activity, which is a weaker measurement than a device. Mortality risk is a matter for a clinician, and nothing in this article is medical advice.

It is not only how much you sit. It is how you sit.

Dr. Flavia P.

Current sedentary behaviour guidelines primarily emphasise total time. There is now evidence that the pattern matters separately from the total.

A cohort study followed 91,292 UK Biobank participants with valid accelerometer data for a median of 12.38 years. Sedentary behaviour was classified using a two-step random forest model, and outcomes covered overall incident cancers and cancer deaths, obesity-related and type-2-diabetes-related cancers, and 23 site-specific cancers.

The models were adjusted for age, ethnicity, deprivation, education, smoking, alcohol, diet and morbidity count. That is a serious adjustment set, and it matters because sedentary people differ from active people in many ways that have nothing to do with sitting.

The study explored the difference between interrupted and prolonged sedentary behaviour, using isotemporal substitution to estimate what happens when prolonged sitting is replaced with intermittent sitting or with physical activity.

The framing is the finding worth carrying: two people can sit for the same total number of hours and be doing something physiologically different, depending on whether those hours arrive in one block or in pieces.

We are reporting this study's design and its central distinction rather than the individual hazard ratios across 23 cancer sites, which are the substance of the paper.

What it changes practically is the shape of the advice. Standing up every half hour is not a consolation prize for people who cannot get to a gym. It is a separate variable that researchers now measure on its own.

This is observational accelerometer data with a long follow-up, which is the strongest form of this evidence available, and it still cannot establish causation.

The number that made us build this

Dr. Flavia P.

The 24-hour movement guidelines integrate physical activity, sedentary behaviour and sleep into a single framework, on the reasonable basis that a day is a fixed budget and these three things compete for it.

A cross-sectional study assessed adherence in 1,469 Spanish university students, mean age 21.6, seventy-one percent women, using validated measures of activity, sedentary behaviour, sleep, psychological distress, self-esteem and resilience. Adherence to all three guidelines was scored on an index from zero to three.

Concurrent adherence to all three guidelines was low, and it varied markedly by field of study: 22 percent in Sport Sciences, and 1.6 percent in Engineering and Architecture.

One point six percent.

Among students studying engineering and architecture, roughly one in sixty met all three basic movement, sitting and sleep recommendations at the same time. These are healthy young people at the physical peak of their lives.

Women showed lower odds of meeting the physical activity recommendation and of meeting all three.

When we say the problem is structural rather than a failure of individual willpower, this is the number we mean. You do not get to 1.6 percent through a generation being lazy. You get there by building environments, courses, jobs and entertainment that make sitting the default and moving the exception.

This is cross-sectional self-report data from one country and one age group, so it captures a snapshot rather than a trajectory, and self-reported activity tends to be overestimated, which would make the real figure worse rather than better.

What I know about screens that the data does not say

Marce P.

I want to be careful here, because this is the part of the article where I stop citing and start telling you something I lived.

I was a lonely teenager. Screens were not what took my life away. For a long stretch they were the only place I had a social life at all. That is the part the simple version of this argument always misses, and I will not let us publish a piece that misses it.

If you are isolated, a screen is not a thief. It is a lifeline. Telling somebody in that position to put the phone down and go outside is advice from a person who has somewhere to go and someone to see when they get there.

So I am not going to sit here and tell you screens are the enemy. I would be lying, and I would be lying about my own life.

What I will tell you is what changed. The screen kept me company, and it also kept me exactly where I was. It was a place to survive isolation, not a route out of it. The connection was real and it was also a holding pattern. I could have stayed in that pattern for years, and plenty of people do.

The thing that moved me was physical. Training gave me a reason to be somewhere at a specific time, in a body, near other people. Not a chatroom about training. The actual room.

That is the whole idea behind this product, and it came from that gap, not from a market study.

What the loneliness research actually found

Dr. Flavia P.

Marce's experience is one person's. Here is what happens when you measure it across a group, and the result is more modest than the headlines about phones and loneliness would suggest.

A cross-sectional survey collected data from 426 young adults aged 18 to 26 using the Bergen Social Media Addiction Scale and the UCLA Loneliness Scale, with correlation analysis, t-tests, analysis of variance and multiple regression examining demographic patterns.

The result: a small yet meaningful link between social media addiction and loneliness, at r = 0.161, p = 0.001.

Read that correlation honestly. It is statistically significant and it is small. An r of 0.161 means social media addiction accounts for a very modest share of the variation in how lonely somebody feels. Most of the story is elsewhere.

The study also found women were more likely to display higher addiction levels, while men reported feeling lonelier.

We are including this precisely because it does not support a dramatic claim. If we wanted to sell you something, we would quote a scarier number. The evidence we found says the relationship is real, measurable, and much weaker than the cultural panic around it.

That is the honest position, and it is also why our argument is not about taking your phone away.

This is cross-sectional data from 426 young adults in one country, using self-report scales, and it cannot establish direction. Lonely people may use social media more, rather than the reverse.

The argument, stated plainly

Marce P and Dr. Flavia P.

Here is what we actually believe, with the evidence attached and the uncertainty left in.

Sitting still for long periods is associated with dying sooner, across 330,000 people in two cohorts on two continents, with figures that agree to three decimal places.

The pattern of that sitting matters separately from the total, which is why interrupting it is its own intervention rather than a consolation.

Almost nobody currently meets the basic movement, sitting and sleep guidelines together. In one field of study it was 1.6 percent.

Screens are not automatically sedentary, and the proxy that says otherwise has now been measured and found unreliable.

The link between social media and loneliness is real and small.

Put those together and you do not get an anti-technology argument. You get something more specific: the problem is not that people look at screens, it is that the screen has become the default destination for time that used to involve a body and other people.

So our position is not less screen. It is that if a screen is going to hold your attention, it should be one that ends with you somewhere else.

That is what we are trying to build. An app whose measure of success is how quickly it gets you off it and into a room, a park, a gym, a session with somebody you know.

We are aware of the tension in that. We are asking for your attention in order to argue that you should spend less of it here.

We would rather sit inside that contradiction honestly than pretend it does not exist.

What we are not claiming

Dr. Flavia P.

A founding document is exactly where overclaiming does the most damage, so let me be explicit about the limits of everything above.

All of the health evidence here is observational. Cohort studies, however large, establish that behaviours and outcomes travel together. They do not prove that changing the behaviour changes the outcome, and people who sit less differ from people who sit more in ways no adjustment fully removes.

The activity measures in the mortality cohorts came from baseline questionnaires, which is weaker than device measurement.

The adherence figures are self-reported and cross-sectional.

The loneliness correlation is small, from one country, and cannot tell you which way the arrow points.

None of this is medical advice. If you have a condition, take medication, are pregnant, or have been told to limit activity, your clinician's guidance overrides anything written here.

What we can say with reasonable confidence is narrow and still worth acting on: moving more, sitting in shorter blocks, and sleeping enough are associated with better outcomes across very large populations, and almost nobody is currently doing all three.

Everything else in this piece is argument, not proof, and we have tried to label which is which.

What to actually do

Marce P and Dr. Flavia P.

Break the blocks. The pattern of sitting is measured separately from the total, so standing up and moving every half hour is a real intervention rather than a token one.

Take any intensity. In the mortality cohort, replacing 30 minutes a day of sedentary time showed comparable protective associations across light, moderate and vigorous activity. Walking counts. You do not need to earn this with suffering.

Stop treating screen time as one thing. Time spent moving while holding a phone is not the same exposure as time spent still, and the research now says so directly.

Use the screen to get somewhere. A message that ends in you meeting a person is doing something a scroll never does.

And if you are isolated right now, do not let anybody shame you for where you found your company. Get the thing that keeps you going, and then use it to get one foot into a room. That order matters, and it is the order one of us actually lived.

Those are our conclusions from the evidence rather than tested prescriptions, and they are deliberately modest.