When I first started teaching at Oxford in 2005, I would offer “office hours” a couple of times a week. They were literally that – time for students to come by my office and chat about anything on their mind. Emails were formal and for rare occasions, with the expectation that most issues would be discussed in person. Fast forward to 2026, and office hours have been replaced at many universities by constant email and Teams communication. These are incessant, with responses often expected within hours, if not minutes, blurring the line between evenings, weekends and normal working hours.

I have to admit that every time a notification pops up on my phone or laptop, even before reading it, I can feel my stress levels rising. It’s made me reflect on how modern communication is pushing our minds to the limit. While most of the recent conversation on mental health and technology has focused on social media, we forget how even older forms of digital communication can push us into a stressful, “always on” way of being.

If we go back to our basic wiring, human brains and society did not evolve in a world of instant, virtual communication. For most of our history, communication occurred face to face within small, stable groups, typically no larger than 150 individuals. Prominent anthropologists say that this is the number of meaningful social relationships we can maintain. Until quite recently, social interaction was in person, and with context – meaning facial expressions, vocal tone, eye contact and body language. We learn a lot not just from someone’s words but their non-verbal cues.

Modern digital messaging has removed this added dimension. In its place, we rely on short, text-based interactions that are stripped of nuance and prone to misinterpretation. And studies show that it is generally more stressful than in-person interaction. For instance, a 2022 study in Boston looked at various forms of communication on levels of participant stress. They found that days with more frequent text messaging were linked to greater stress and more negative feelings, while days with in-person contact were linked to feeling more positive. A 2026 review of numerous studies on texting versus in-person interaction found the same: quite simply, our wellbeing is higher with in-person interaction versus screen-based communication.

Which brings me to two blue ticks, which signal if a message has been read, a step even further than just pure texting used to be. As such, it’s brought a new source of stress and emotional burden for many people. From a neuroscience perspective, delayed or ignored messages can activate the same brain regions associated with physical pain, particularly the anterior cingulate cortex and the anterior insula. This is known as social pain, and it reflects the way our brains respond to exclusion or rejection.

When someone abruptly ends communication without explanation, often called “ghosting” or “to patch” someone, it can feel incredibly painful. For nearly all of human history, people lived in small, tight-knit groups where disappearing from someone’s life wasn’t an option. You couldn’t simply vanish. Modern studies show that unexplained disconnection in romantic relationships activates our biological alarm systems, including raised stress levels, heart rate and blood pressure, that push us to do something to restore the bond or seek an explanation: “But why did they ghost me? What did I do?” Without a narrative, our brain has no way to resolve what has happened.

Even short periods of being left unread, or “on read” and receiving no reply, can lead to feelings of micro-rejection, because the brain is primed to detect tiny shifts in social availability, and it can be especially hard for those who already suffer from low self-esteem. We are wired for in-person conversation: not waiting for a response that could come instantly if the other person chooses to engage … but doesn’t.

There is a parallel group: those who feel pressured to reply quickly, especially when they’ve been seen online or their message has been marked as read. The introduction of read receipts and the ability to see when someone is typing, or last online, has intensified the pressure to be constantly present. These features create an environment where you may feel as if you have to engage, even if you don’t want to, to avoid appearing rude or emotionally distant.

This constant availability to others has consequences. The brain’s cognitive function system, which is responsible for decision-making, can easily become overloaded by the demands of digital interaction. Every notification represents a small decision: should I respond now, later or just forget about it? Multiply this by dozens of times a day and this constant multitasking leads to cognitive fatigue and emotional exhaustion.

We have study after study on high rates of burnout, exhaustion and loneliness, not just in the UK but globally. We’re more in touch than ever, yet more lonely and stressed than ever before. Perhaps it’s because our nervous systems were designed for immediate, tangible threats, not for the constant pinging in our pocket – and the stress of being left unread.

• Prof Devi Sridhar is chair of global public health at the University of Edinburgh, and the author of How Not to Die (Too Soon)