We clean a lot of things, but one item many people ignore or forget about is the wrist strap of their fitness device. This is because the plastic or rubber strap harbours bacteria, deriving nutrients from our sweat.
With traditional watches, this focus on antimicrobial reduction was less important since many metals possess antimicrobial activity or at least create conditions whereby bacteria and fungi do not grow or increase in number.
With fitness trackers, if only a small proportion of wearers forget to routinely disinfect their straps, the impact could be significant. This is given the number of people who own fitness devices: around 229 million people wear Apple Watches and 120 wear Fitbits. Societal trends suggest that routine cleaning of wristbands is commonly ignored due to perceived lack of need and ignorance of the sanitation process.
As to the extent of the issue, Florida Atlantic University researchers tested wrist straps of different materials including rubber, plastic, cloth, leather and metal. This was to assess how the type of material impacted the bacteria found on the strap. The general finding was that 95 percent of the wristbands in the sample were contaminated with bacteria. A related study from Tirunelveli Medical College scientists draws similar conclusions.
As well as the total population, the researchers assessed fitness trackers for potentially pathogenic species of Staphylococcus (including S. aureus), Enterobacteria (like Escherichia coli), and Pseudomonas, which can all cause infections under certain conditions.
The actual microbial population diversity partly relates to the habits of the user (for example, wearing a fitness tracker to a bathroom picks up a greater array of contaminants).
Of the different materials, rubber and plastic bands had the most bacteria on them. This suggests that porous and static surfaces tend to attract and be colonised by bacteria.
There were no noticeable differences between male and female participants in the study, though the activities engaged in did have an effect. For example, those nagging in physical activity, such as gym goers, had the highest levels of staphylococcal bacteria.
Among other findings:
- The pathogen Staphylococcus aureus was found on the hands of 64 percent of fitness tracker wearers and 36 percent non-wristwatch wearers.
- The watch wearers had higher counts of bacteria on their wrists than on their hands.
- The removal of the watch prior to the sampling resulted in increased counts of bacteria on both the hands as well as on the watch wrist as compared to that in the non-watch wearers.
- Wearing a wristwatch results in an increase in the bacterial contamination on the wrist, but excess hand contamination does not occur unless the watch is manipulated.
In terms of suitable disinfectants to use, a 70 percent alcohol wipe or spray (such as ethanol or isopropanol) will be effective against most organisms. If alcohol is not available, apple cider vinegar (a type of vinegar made with crushed fermented apples, yeast, and sugar) will exert some effect. Alternatively, some companies integrate antimicrobial materials into their wrist bands.
According to lead researcher Nwadiuto Esiobu: “”The quantity and taxonomy of bacteria we found on the wristbands show that there is a need for regular sanitation of these surfaces.”
He adds: “Even at relatively low numbers these pathogens are of public health significance. Importantly, the ability of many of these bacteria to significantly affect the health of immunocompromised hosts indicates a special need for healthcare workers and others in hospital environments to regularly sanitize these surfaces.”
For hospital staff who might be caring of immunocompromised patients, a policy of ‘bare below the elbows’ is probably best (i.e. do not wear any device of any kind whilst attending patients).
The research appears in the journal Science Advances, titled “Wristwatches as the Potential Sources of Hospital-Acquired Infections” and in Advances in Infectious Disease, titled “Prevalence and Disinfection of Bacteria Associated with Various Types of Wristbands.”
Other potential forms of bacterial transmission and facilitation of infection include earbuds or cell phones.
