In 1946, a new advertising campaign appeared in magazines with a picture of a doctor in a lab coat holding a cigarette and the slogan, “More doctors smoke Camels than any other cigarette.” No, this wasn’t a spoof. Back then, doctors were not aware that smoking could cause cancer, heart disease and lung disease.
In a similar vein, some researchers and consumers are now asking whether wearable computers will be considered harmful in several decades’ time.
We have long suspected that cellphones, which give off low levels of radiation, could lead to brain tumors, cancer, disturbed blood rhythms and other health problems if held too close to the body for extended periods.
Yet here we are in 2015, with companies like Apple and Samsung encouraging us to buy gadgets that we should attach to our bodies all day long.
While there is no definitive research on the health effects of wearable computers (the Apple Watch isn’t even on store shelves yet), we can hypothesize a bit from existing research on cellphone radiation.
The most definitive and arguably unbiased results in this area come from the International Agency for Research on Cancer, a panel within the World Health Organization that consisted of 31 scientists from 14 countries.
After dissecting dozens of peer-reviewed studies on cellphone safety, the panel concluded in 2011 that cellphones were “possibly carcinogenic” and that the devices could be as harmful as certain dry-cleaning chemicals and pesticides. (Note that the group hedged its findings with the word “possibly.”)
The W.H.O. panel concluded that the farther away a device is from one’s head, the less harmful — so texting or surfing the Web will not be as dangerous as making calls, with a cellphone inches from the brain. (This is why there were serious concerns about Google Glass when it was first announced and why we’ve been told to use hands-free devices when talking on cellphones.)
A longitudinal study conducted by a group of European researchers and led by Dr. Lennart Hardell, a professor of oncology and cancer epidemiology at Orebro University Hospital in Sweden, concluded that talking on a mobile or cordless phone for extended periods could triple the risk of a certain kind of brain cancer.
There is, of course, antithetical research. But some of this was partly funded by cellphone companies or trade groups.
One example is the international Interphone study, which was published in 2010 and did not find strong links between mobile phones and an increased risk of brain tumors. The Centers for Disease Control and Prevention concluded in 2014 that “more research is needed before we know if using cell phones causes health effects.”
Another study, in The BMJ, which measured cellphone subscription data rather than actual use, said there was no proof of increased cancer. Yet even here, the Danish team behind the report acknowledged that a “small to moderate increase” in cancer risk among heavy cellphone users could not be ruled out.
But what does all this research tell the Apple faithful who want to rush out and buy an Apple Watch, or the Google and Windows fanatics who are eager to own an alternative smartwatch?
Dr. Joseph Mercola, a physician who focuses on alternative medicine and has written extensively about the potential harmful effects of cellphones on the human body, said that as long as a wearable does not have a 3G connection built into it, the harmful effects are minimal, if any.
“The radiation really comes from the 3G connection on a cellphone, so devices like the Jawbone Up and Apple Watch should be O.K.,” Dr. Mercola said in a phone interview. “But if you’re buying a watch with a cellular chip built in, then you’ve got a cellphone attached to your wrist.” And that, he said, is a bad idea.
(The Apple Watch uses Bluetooth and Wi-Fi to receive data, and researchers say there is no proven harm from those frequencies on the human body. Wearables with 3G or 4G connections built in, including the Samsung Gear S, could be more harmful, though that has not been proved. Apple declined to comment for this article, and Samsung could not be reached for comment.)
Researchers have also raised concerns about having powerful batteries so close to the body for extended periods of time. Some reports over the last several decades have questioned whether being too close to power lines could cause leukemia (though other research has also negated this).
So what should consumers do? Perhaps we can look at how researchers themselves handle their smartphones.
While Dr. Mercola is a vocal proponent of cellphone safety, he told me to call him on his cell when I emailed about an interview. When I asked him whether he was being hypocritical, he replied that technology is a fact of life, and that he uses it with caution. As an example, he said he was using a Bluetooth headset during our call.
In the same respect, people who are concerned about the possible side effects of a smartwatch should avoid placing it close to their brain (besides, it looks a little strange). But there are some people who may be more vulnerable to the dangers of these devices: children.
While researchers debate about how harmful cellphones and wearable computers actually are, most agree that children should exercise caution.
In an email, Dr. Hardell sent me research illustrating that a child’s skull is thinner and smaller than an adult’s, which means that children’s brain tissues are more exposed to certain types of radiation, specifically the kind that emanates from a cellphone.
Children should limit how much time they spend talking on a cellphone, doctors say. And if they have a wearable device, they should take it off at night so it does not end up under their pillow, near their brain. Doctors also warn that women who are pregnant should be extra careful with all of these technologies.
But what about adults? After researching this column, talking to experts and poring over dozens of scientific papers, I have realized the dangers of cellphones when used for extended periods, and as a result I have stopped holding my phone next to my head and instead use a headset.
That being said, when it comes to wearable computers, I’ll still buy the Apple Watch, but I won’t let it go anywhere near my head. And I definitely won’t let any children I know play with it for extended periods of time.