Most of us don’t notice the physical cost of scrolling until something starts to ache: a stiff neck after a long commute, a sore thumb at the end of the day, or eyes that feel dry long before bedtime. Experts say those small signals can reflect the way prolonged phone use affects the body — though the science is more nuanced than simply blaming your screen.

The posture doctors call “text neck” is simple to picture: chin down, head forward, eyes on the screen. A physiotherapy review in the journal Work explains that this sustained forward-flexed position changes muscle activation patterns in the cervical and thoracic spine, leaving the upper trapezius and neck extensors working overtime to hold the head up against gravity, which shows up as tightness across the top of the shoulders.

Here is where the evidence gets more careful than the popular narrative. A 12-month longitudinal study of 457 adults, published in the Brazilian Journal of Physical Therapy in November 2025, measured people’s actual neck-flexion angle while texting and found it did not predict who went on to develop neck pain a year later.

What did predict it: poor sleep quality raised the odds by 76%, and insufficient physical activity nearly two-and-a-half times. The correction that actually helps, per the physiotherapy literature, is simple: raise the phone toward eye level rather than bending the neck down to meet it, and take frequent breaks to reverse the flexed position.

Unlocking a phone dozens or hundreds of times a day loads a very small tendon compartment at the base of the thumb. A cross-sectional study of 155 young adults published in the Indian Journal of Orthopaedics in November 2025 found daily unlock frequency and screen time were both significantly correlated with a positive Finkelstein test, the clinical exam for De Quervain’s tenosynovitis, an inflammation of the tendons that move the thumb.

Nearly a third of participants tested positive. The fix: alternate which thumb or finger unlocks and scrolls, and rest the wrist in a neutral position rather than bent to the side.

Staring at a screen suppresses the automatic blink reflex. A study published in the journal Eye, from the Nature portfolio, tracked children’s blinking during smartphone gaming and found blink rate dropped from 20.8 to 8.9 blinks per minute within the first minute of play, with interblink intervals nearly tripling.

Fewer blinks mean less fresh tear film spread across the eye, which is what produces the classic dry, gritty feeling. The correction is the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds, which resets both focus and blink rate.

Screens emit concentrated blue wavelengths that suppress melatonin, the hormone that signals the brain it’s time to sleep. Harvard researchers compared 6.5 hours of blue light exposure to equally bright green light and found the blue light suppressed melatonin for about twice as long and shifted circadian rhythms by twice as much, three hours versus 1.5. The fix physicians recommend is straightforward: stop looking at bright screens two to three hours before bed, or use a blue-light filter if that’s not realistic.

None of these signs mean phones are dangerous in the way headlines sometimes suggest. They’re closer to the repetitive strain injuries any prolonged, awkward, or repetitive posture produces, mechanical wear rather than a verdict on modern life. Noticing which of these five shows up first is a reasonable cue to adjust posture, screen distance, or timing before it becomes a habit worth treating.