It happened ago just over a year. Montserrat Aguilar had completed her day as a cleaning service worker in Barcelona when, already at home, collapsed and died. He had spent hours sweeping the streets of Raval in the sun on a day when temperatures in Barcelona exceeded 35ºC. Although at the beginning of 2026 the family I was still waiting based on the results of the final autopsy, his death unleashed a intense (and bitter) debate about the conditions faced by workers who, like her, walk the streets during heat waves.
This year in Barcelona they wanted to cure their health with technology well known in Japan: bracelets capable of anticipating heat strokes.
What has happened? that in full extreme heat wavewith the thermometer exceeding 40ºC In Barcelona, the Barcelona City Council has decided to reinforce the security of the operators who provide public services on the street using technology. A few weeks ago he distributed 1,400 bracelets thermal among the staff responsible for keeping the city clean, providing public lighting and taking care of the garden areas.
Is it the only measure? No. The Newspaper precise other measures with which Barcelona wants to prevent extreme temperatures from taking their toll on those who work on the street. For example, adapting the workday of gardeners in summer, advancing the start and end times to avoid the most dangerous periods, or adopting special protocols, designed for the dog days.
Is it enough? No. Sensors and protocols are welcome, but unions insist they are not enough. “Non-exposure is the best prevention,” claims Carlos del Barrio, from CCOO, in The Newspaper. Workers’ representatives recall that “no measure is sufficient on its own” and demand greater investment to, among other things, add air conditioning to cars.
Without going any further, the Commissions remember that a relevant part of the fleet is still not acclimatized and there are even vehicles (such as irrigation vehicles) that have the engine located right under the seat, something not very desirable in August.
How do the bracelets work? They basically fit the operator’s wrist and control their temperature. When they detect that it rises too high and approaches dangerous levels, it emits a signal (vibrates and lights up) so you can take action. In Barcelona has it happened before. When this happens and the thermal bracelet issues its warning, the operator must stop, find a shady place, drink water and inform his supervisor. The bracelet itself will inform you with a light signal (green, in this case) when you are ready to continue.
In the specific case of Barcelona, Parks and Gardens has invested almost 60,000 euros in sensors from the company Metalco, devices designed to warn the user “two levels before” of heat stroke. “It is set to activate the alarm when the deep temperature reaches approximately 38ºC.”
That is the general guideline. In practice, the sensor must take into account the conditions of each user. The Department of the Interior has also opted for a similar solution, with devices for the Mossos and firefighters.
Is it something new? Thermal bracelets have been used for a long time. And they are certainly not exclusive to Catalonia or Spain. As I remembered a few days ago The Confidential There is a Japanese company that has been dedicated to them for a few years now: Biodata Bankcreated in 2018 and with headquarters in Tokyo.
Its catalog includes Canaria+, a bracelet designed to detect “subtle changes in thermal stress” and that helps the wearer control their rest, hydration and food. When the sensor detects that the body is having difficulty dissipating heat, it issues a warning with light, sound and vibration. The moment it thinks the risk has disappeared, it reports again with a green light.
“We felt it was necessary to have a system in place and take action before a person collapsed,” explains the company’s CEO, Takeshi Anzai. Regarding his bracelet, he clarifies that “the algorithm adapts” to whoever uses it, although it starts from four levels. The first is free of danger, with the temperature below 37ºC. The second rises to a maximum of 38.3ºC and reveals a “latent risk.” With the third (37.7-39ºC, depending on the person) the alerts go off.
The last, the most critical, ranges from 38.7 to 40ºC.
Is it only used in Spain? At all. In fact Japan is another good example. Last year the World Economic Forum actually dedicated an extensive report to the “lessons” that the country offers to overcome extreme heat waves and among its resources included wrist sensors designed to detect sudden increases in body temperature and, thus, prevent heat stroke.
One of the organizations that has opted for them there is the Tokyo Metropolitan Government, which has distributed thermal bracelets among elderly people with reduced mobility, teachers and students who go to public schools and certain workers who have to work outdoors.
“In Japan last year the number of people urgently transported due to heat stroke exceeded 100,000. In cities like Tokyo, the demand for ambulances became so high that authorities issued alerts asking the population to make appropriate use of emergencies,” remember Anzai.
Images | Barcelona City Council 1 and 2 and Biodata Bank
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