LONDON (AFP) - Users of smartphones and tablet computers are starting to get high-tech blues, as increasing numbers of the tech savvy are coming down with ailments from text neck to text thumb injury. Health experts in Britain have warned that the strain injuries stemming from long periods spent staring at small screens and tapping at tiny keys can be debilitating. And the injuries are becoming more common as high-tech gadgets grow ever more popular. More and more Britons use their smartphones in effect tiny PCs that fit in a jacket pocket for accessing the Internet rather than making phone calls. According to a recent YouGov poll, 44 percent of Britons use their mobile phone for activities other than making calls, for between 30 minutes and two hours a day. The pollster quizzed 2,034 adults over several days in September. I had a patient who developed inflamed tendons in her thumb from using her smartphone and was unable to use her hand for weeks due to pain, said Tim Hutchful from the British Chiropractic Association. Sammy Margo of the Chartered Society of Physiotherapy said that peoples bodies are not designed to be used like this. The phones are far too small, with keys that are too small, she said, noting that pain in the upper limbs forced one of her patients to stop texting and instead switch to voice recognition software.