Cellphones, essential as they are, get us into trouble sometimes.
We text or talk when we're driving or crossing the street, and increase the risk of crippling our thumbs with too much tapping.
But researchers are finding even more ways that mobile phones impact -- and reveal -- our well-being.
One recent study by Italian researchers found that talking on a cellphone pushed blood pressure higher by several points in group of 94 subjects with an average age of 53 and with mild hypertension. Average beating heart pressure went from 121 to 129; resting heart pressure went from 77 to 82.
But they found that there was very little change in pressure during calls among a subset of patients who typically received or made 30 or more calls a day. The work was presented during the American Society of Hypertension in San Francisco earlier this month.
Other studies over the years have documented the phantom vibration response some people hooked on their mobile devices perceive. Some experts say the phenomenon raises questions about how much our phones get into our heads. Another recent study illustrates how it can be the other way around.
How we hold and listen to a cellphone seems to reveal which side of our brain is dominant when it comes to speech and language skills, according to researchers at Henry Ford Hospital in Detroit.
Their report, published online earlier this month, was based on a survey of 5,000 head, neck and ear patients, 90 percent of whom were right-handed.
An overwhelming majority - 68 percent of the righties and 72 percent of the lefties - used their dominant hand to hold the phone to the ear on the same side, with the rest using the opposite hand and about 6 percent using both hands.
Left-brain dominant people make up about 95 percent of the population, most of whom are right handed. The dominant side of the brain is the location for speech and language functions.
The study offers a possible alternative to an invasive test used to map brain activity and dominance in people with brain injuries, disorders or tumors.
And, Dr. Michael Seidman, who led the study, said the results offer some reassurance that cellphone use may not be as closely tied to tumors of the brain, head and neck as some fear. That's because such tumors are fairly evenly split between the two sides of the head, while most people hold the phone on the right side.
Research into the radiation effects of mobile phones has given mixed results on whether they contribute to brain tumors. And there is concern that since the technology has only been widespread for about 20 years, the effects of long-term exposure remain unknown.
The Federal Communications Commission, which already limits the strength of phone radiation emissions, recently announced it would conduct a new review of the evidence, focusing particularly on exposures to children and teens. About 87 percent of American adults have a mobile phone, and the rate may be even higher for adolescents.
Another team from Henry Ford recently reported on another example of a mobile device revealing a previously undetected medical problem. It described the experience of a 40-year-old man who was unable to write a comprehensible text message, even though all his other language abilities -- speech, reading, handwriting and comprehension -- were normal.
The man had a slight weakness on the right side of his face, but otherwise seemed healthy. After a second day of garbled texting -- which he viewed as accurate -- his doctors determined that he had suffered a stroke caused by a blood clot. They told the American Academy of Neurology that this "dystextia" might become a useful tool in diagnosing such strokes.
(Contact Scripps health and science writer Lee Bowman at BowmanL@shns.com .)