I first heard about my friend Adam’s curious new habit in a busy pub. He said he’d been doing it for over a year, but had never spoken to anyone about it before. He had a furtive look around, then took out his phone and showed me the product of his burning obsession: a spreadsheet.
This was not a record of his annual tax return or numbers he was crunching for work (Adam is a data scientist). Instead, it was a spreadsheet recording the minutiae of his life, with dozens of columns tracking every element of his daily routine. It all started, he told me, because of a recurring argument with his boyfriend. His partner didn’t think they spent enough time together, but Adam thought that they did. There was only one way to settle this, he decided: cold, hard data. So he began keeping a note of the days they saw each other and the days they didn’t.
“It started with just that one element,” he told me, “but then you’re like, is there more stuff to track?” The spreadsheet expanded; soon, he was tracking his sleep, social engagements, exercise regime and cultural intake. He even started to record, on a scale of one to eight, how much cheese he had eaten that day (it’s worth pointing out here that Adam is French – I can only imagine the carnage of a day that notches up the maximum eight out of eight on the cheese scale).
While gathering data about our lives might once have been a fringe pursuit for Silicon Valley tech nerds, now it’s just an everyday activity for many of us. We track our step counts, calories consumed, exercise completed, menstrual cycle or hours slept. We list books we’ve read on Goodreads, our top films on Letterboxd, or share our most-played music via the data presented by Spotify Wrapped.
Today an average smartphone has a host of self‑tracking tools built in – the iPhone Health function can help you keep track of your mood, mobility and nutrition, but also sexual activity, toothbrushing and time spent in daylight. Then there are the tracking tools: smartwatches on wrists, smart rings on fingers, Zoe glucose monitoring patches on arms, fitness trackers turning every step of that parkrun into thousands of data points. The latest is a £210 device that promises to monitor blood pressure, 24/7. In a recent YouGov poll, almost 40% of Britons surveyed said that they own a wearable device.
Beneath all this is a promise: understand your life better with data, and you can improve it. The idea is seductive, especially when tech companies offer tools that they say will make it easy. But can a human life be reduced to a dataset? Can a body be tuned up like a machine? Or is this explosion of self‑tracking simply narcissism redesigned for the age of big data, by a society that has internalised the tech industry maxim that more data is always better?
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To investigate self-tracking, it felt only right to conduct my own experiment. Over three months, I tracked 15 variables about my life every day, recording my sleep, exercise and screen time, health complaints, spending, cultural consumption and social plans, and rating my mood and my work productivity out of 10. I mostly used a spreadsheet and my phone to record data, though I also included an Oura smart ring (which records sleep, heart rate, temperature and activity) in the mix halfway through the project.
The quest for self-knowledge is a story as old as time: in the 18th century, at the age of 20, Benjamin Franklin identified 13 essential values he wanted to cultivate, many of which seem very remote from the aspirations of today’s 20-year-olds. They were temperance, silence, order, resolution, frugality, industry, sincerity, justice, moderation, cleanliness, tranquillity, chastity and humility. Dividing the day into six time periods, Franklin put a black mark in his notebook each time he violated a virtue.
Reflecting on the process later in life, he decided that it had been helpful, writing in his autobiography: “Though I never arrived at the perfection I had been so ambitious of obtaining, but fell far short of it, yet I was, by the endeavour, a better and a happier man than I otherwise should have been if I had not attempted it.”
Widespread self-tracking only became a realistic prospect for ordinary people in the early 2010s, when a confluence of new technologies including mobile data, wearable tech, GPS and biosensors significantly lowered the barriers to entry.
A few years earlier, two editors for Wired magazine, Gary Wolf and Kevin Kelly, had coined the term “quantified self”. Data had transformed the worlds of economics, government, science and technology, they argued, so why not bring its power to bear on our bodies and daily lives? They fostered a community of artists, academics and early tech adopters who began to meet regularly in the Bay Area of California, before expanding into an international network. “The promise was that self-tracking could give us more ability to solve our problems and to answer our questions in daily life,” Wolf tells me.
Rather than using commercial tools to track common metrics like calories or running speed, the members of the Quantified Self community often pick hyperspecific attributes to track, and build their own tools for the purpose. On their online forums, people discuss their tracking of headaches, outbursts of anger, longevity of nail polish and rate of hairline recession. “How much fish oil is right for me – 2 years of testing” trumpets one thread (the answer was half a tablespoon a day).
One tracker looked for a relationship between their anxiety levels during the Covid-19 pandemic and the number of times they burped each day. The graphs show that the two rose and fell in tandem, but this might also be a lesson in not mistaking correlation for causation. For example, it is possible to point to data that shows that more people drown in swimming pools in the years when more Nicolas Cage movies come out, but that doesn’t mean Cage’s acting causes the drownings.
Some trackers successfully solve specific problems using data. In a bid to cure serious allergies, the Danish tracker Thomas Blomseth Christiansen made an app where he tracked every time he sneezed over five years, trying to find the triggers. After rigorous analysis and experimentation, he reported that he was able to stop sneezing almost entirely.
While this kind of data-driven approach to the messy business of living may seem cold and analytical to some, it only takes a casual look at trackers’ datasets before you start observing deeply human moments, like short stories buried in the spreadsheets. A woman called Valerie Lanard tracked her excuses for not exercising, which included a column detailing whether she was suffering from a cold at the time, and, intriguingly, the probable cause of the virus. Often this was work or family, but in one solitary cell the suspected reason for illness reads “Kissing”. When I saw this, I felt strangely pleased for Valerie.
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Not everybody finds their tracking experiments useful. For three years, Felix Krause, a 30-year-old tech worker who lives in Austria, ran a website where he constantly shared his live location as well as daily data about his exercise, sleep and mood. He ended up with some mildly interesting insights. In warmer climates he was more likely to go to the gym. He was less happy on days with more video calls. On days where he consumed more than four alcoholic drinks he was 21 times more likely to dance. Despite the work of collecting data, he appreciated that the process made him pause and reflect regularly: “When the bot asked me four times a day how I was feeling, it was good to have that little check-in and think, how am I really feeling?”
But, ultimately, there were no revelations. He abandoned the project in 2022, adding a note to his site: “When I first started building this project three years ago, I expected to learn way more surprising and interesting facts … retrospectively, it did not justify the hundreds of hours I invested in this project.” When I speak to him, he tells me that his life has recently improved for a very non-quantifiable reason – he fell in love. “I’m in a good relationship, so I’m feeling way better than I did back then,” he says. “It’s not about the food I eat, or the CO2 levels in our bedroom, but being in this relationship is overshadowing all those other factors.”
With time, the term “quantified self” faded from use. Wolf argues that this isn’t because the idea was wrong, but that it’s become such a common part of daily life that it no longer needs a name. “I think, as a phrase, ‘quantified self’ has done what it had to do,” he says.
One group that benefits significantly from self‑tracking is those with long-term health conditions. People living with chronic fatigue syndrome or long Covid have found tracking tools useful for understanding their symptoms, “often in the face of gaslighting by their doctors and being told it’s psychosomatic”, says Prof Deborah Lupton, a sociologist with a focus on health, at the University of New South Wales. “So for people whose symptoms are undiagnosed, unrecognised or disbelieved, self-tracking can be a really important way of finding validation.”
Meanwhile, for people living with diabetes, arm‑worn blood glucose monitors can be connected to a phone app. Ellie, a 31-year-old postgraduate researcher who was diagnosed two years ago, tells me that self‑tracking technology is “a total gamechanger”, making blood sugar management much easier. There can be tension, however, between people who track for different reasons. Ellie met people at her local yoga studio using a blood glucose monitor from the wellness company Zoe, which is intended to help users improve their nutrition. “I have had someone say, ‘Oh my God, are you doing Zoe?’ And I’m like, ‘No, babe, I’m doing type 1 diabetes.’”
Despite a wealth of scientific literature on the topic, there is no consensus on how helpful self-tracking technologies are. Several studies show that fitness trackers can help motivate people to exercise, but the evidence is inconclusive on whether they can help them lose weight. There is as yet no scientific consensus that personalised nutrition programmes like Zoe are any better than standard advice. In many cases, the effectiveness of digital tracking tools is not shown to be any better than analogue methods.
Self-tracking might even do more harm than good. One therapist I spoke to who works with patients living with obsessive-compulsive and eating disorders told me that patients can become fixated on their tracking data, punishing themselves if they haven’t walked enough steps in a day or have eaten more than a certain number of calories. One scientific study flagged that calorie trackers can feel “oppressive and punishy” to their users.
This type of thinking can also affect neurotypical trackers. Turning your life into data creates the illusion that there is a perfect version of yourself that you’re forever chasing. For a few weeks of my self-tracking experiment I had an injured foot. I found it demoralising to write “None” every day in the exercise column of my spreadsheet. Btihaj Ajana, a professor of ethics and digital culture at King’s College London, says: “There’s always this feeling of, I could do better, I could do more – and it’s never-ending. That’s a recipe for anxiety, distress and never being content.”
And there’s another potential pitfall: data privacy. Users frequently share sensitive data about their health, location and finances with private companies without a clear understanding of where it is stored and how it might be used. Tracking and wearables companies often have vague wording in their privacy policies that obfuscates where your data might be going – theoretically, it could be used to tailor targeted ads, affect your insurance rates, or for identity theft.
These services are vulnerable to hacking. In 2018, the data of 150 million users of the MyFitnessPal app was exposed in a breach. In 2021, a hack of the company GetHealth exposed the records of 61 million users of platforms including Apple Health and Fitbit. A 2023 hack of DNA testing site 23andMe exposed the data of 6.9 million users, a 98% fall in its share value a year later and leaving some customers nervously attempting to delete private data stored on its servers.
And some of the companies are downright shady. While planning my own self-tracking experiment, I looked into analysing my body’s microbiome with a service called uBiome. After some Googling, however, I learned the company’s founders had had their offices raided, been charged with fraud and money laundering, fled to Germany, and are now considered fugitives by the FBI. I therefore opted not to send them genetic samples from my mouth, gut and genitals.
Even without data breaches, your tracking data could find its way to places you would never expect – like a court of law. In 2015, a woman in Pennsylvania alleged to police that she had been sexually assaulted, but the police ended up charging her with the crime of filing a false report, in part because her Fitbit showed she was awake at the time of the crime, when she claimed to be asleep. “When she bought her Fitbit, she didn’t realise one day it would become a witness against her,” says Ajana. Later, when the federal right to abortion was overturned in the US in 2022, women were advised to delete their period tracking apps for fear that data concerning their menstrual cycle could be used to accuse them of having illegal abortions in a criminal case. This has not happened yet, but is thought to pose a real danger.
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After three months of tracking my life, I enjoyed some of the observations from analysing my data, but didn’t discover anything wildly new about myself. I took an average of 6,737 steps a day. My average mood was 7.4 out of 10. My average screen time on my phone was three hours and 30 minutes, or 20% of my waking hours – this felt excessive, but the vague interventions I made to reduce it were unsuccessful. My Oura ring once correctly predicted I was getting sick a day before I realised it myself, and also revealed that I sleep less than I expected – closer to six hours a night than eight. Calculating my average daily spending was a horrifying experience that I’m not keen to repeat. The spreadsheet’s “Health” column was full of minor grievances relating to hangovers, skin irritation or back pain. One recurring entry simply says, somewhat mysteriously: “Still on the mend.”
At the beginning, I had enjoyed filling in the spreadsheet and felt that by tracking I was taking control of my life. But as it went on, I realised that I was simply creating busywork for myself. Did I need an app to tell me that I was feeling bloated after stuffing myself with pizza? Or that I felt good on days where I exercised or saw my friends? Why did I need to outsource these observations to a phone, watch or ring, when there was another piece of sophisticated technology – my body – that could provide the answers?
The limitations of my tools were also clear. My phone told me that on 7 December at 2am I’d walked 587 steps, but I know I was asleep in bed. Clearly it was wrong: even if I had been sleepwalking, I wouldn’t have taken my phone along. If you look at my Oura smart ring app on the night of the 12 January, you will see my heart rate spike dramatically at 11pm, then flatline completely. You would have to assume that I’d had a heart attack and died. In fact, I was running a fever and, frustrated by the weight of the ring on my finger, tore it off and threw it across the room.
Without any data expertise, I struggled to extract much meaning from the data I’d gathered. So what good was this data doing me? “Western society thinks in a very quantitative way, believing that more is more, and more data is better than less data,” says Ajana. “But that’s not necessarily the case, because data in itself is just noise. It’s the analysis that goes into it, the fine‑grained study of it, which makes it useful.”
As we track every run on Strava and every heartbeat on our smartwatches, we usher in a society where the quantitative outweighs the qualitative. It’s an ideology we’re surrounded by, as modern governments promote data-driven approaches for social problems, and banks, healthcare systems and even national borders increasingly rely on digital systems and biometrics.
I asked experts why my self-tracking regimen yielded so few revelations. These days, Wolf is focused on a related field called “personal science”, which focuses on how to make self-tracking data meaningful to your life. “If you spend a little time thinking and refining your questions, you’ll be better able to judge what tools you actually need,” he says. If, by contrast, you start with the tool, you may be buying into metrics that might not be relevant to you.
There is no need to accept a tech company’s rules for what is the right amount of exercise, calories or sleep for your particular body. If your body is telling you one thing and the app another, trust your body – it’s unlikely that a mass-produced tech product can know you better than you know yourself.
I catch up with my friend Adam to see how his spreadsheet is going, six months after I first saw it. He tells me that he’s still using it, but in a more targeted way. He has found it helps to motivate him to go swimming regularly, but has decided to stop tracking data on his romantic relationship. “If you’re lost in life, you won’t find answers in the data you’re collecting,” he says. “If you’re asking yourself tough questions, a therapist is going to be more useful.” One clear decision he has made, however, is to stop tracking how much cheese he is eating each day – and he says he is happier as a result. Perhaps there are some things that it’s better not to know.
