Smartwatches have been hailed as a game-changer for our health, even saving the odd life here and there.
And yet, scientists are warning wearers could be at risk of getting sick after a study looked at the harmful bacteria hiding in the wristbands.
Researchers at Florida Atlantic University analysed different types of wristbands commonly used for smartwatches and found 95 per cent of the 20 different wristbands tested were contaminated with bacteria capable of causing disease.
"The quantity and taxonomy of bacteria we found on the wristbands show that there is a need for regular sanitation of these surfaces," biological scientist and senior author of the study Nwadiuto Esiobu said of the results.
"Even at relatively low numbers these pathogens are of public health significance."
Specifically, the study, published in the journal Advances in Infectious Diseasesfound rubber and plastic bands had the most bacteria on them, while metal bands like gold and silver were virtually free from bacteria.
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"Plastic and rubber wristbands may provide a more appropriate environment for bacterial growth as porous and static surfaces tend to attract and be colonised by bacteria," Esiobu added.
The most common bacteria found on the bands were Staphylococcus, Enterobacteria (like Escherichia coli), and Pseudomonas, which can be responsible for a variety of infections, including abscesses, pneumonia, and salmonella.
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The level of bacteria is impacted by things like skin, sweat, and environment, with the wearers type of activity also playing a role.
Researchers particularly warned those with weakened immune systems that smartwatches could lead to severe infection.
"The ability of many of these bacteria to significantly affect the health of immunocompromised hosts indicates a special need for health care workers and others in hospital environments to regularly sanitise these surfaces," Esiobu said.
It is recommended people clean their wristbands regularly with soap and water or an alcohol-based disinfectant.