"Smart" Wristbands Warn of Heatstroke Risk in Spain

In Spain, thermal-monitoring wristbands are gaining popularity — devices that warn of heatstroke risk before a person even notices something's wrong. Heatstroke is treacherous precisely because in 80% of cases, a person realises it too late. The Japanese startup Biodata Bank has come up with a solution.

How the "Smart" Wristbands Work

The wristband's name (Canaria+) is a nod to the canaries that miners used to take with them underground. If the bird, with its sensitive respiratory system, showed signs of weakness, people would leave the mine, since that meant invisible toxic gases were present. Now technology plays the role of the canary.

The wristband is turned on with a single button at the start of the day and records the wearer's baseline body temperature. In direct contact with the skin, it tracks changes every minute and gives a signal (sound, light, and vibration) when the fluctuation exceeds one degree. In that case, the person is advised to stop, rest for ten minutes, drink water, and go back to what they were doing once the red indicator turns green again.

The wristband's algorithms build up the user's individual data and, over time, give warnings with increasing accuracy — earlier than the person would notice something's wrong on their own.

"Under normal conditions, the body has a thermoregulation mechanism that makes you sweat or warms your skin. But some factors can keep you from noticing this, such as stress, lack of sleep, or alcohol consumption. The wristband warns you, and as it learns your individual data through its algorithms, it becomes increasingly accurate," explains Jaime de Andrés, co-director of Biodata Bank's Spanish division.

Who Is Buying the Wristbands in Spain

More than a hundred organisations in Spain have already bought wristbands from Biodata Bank, including Catalan firefighters and police. In addition, the government of Extremadura has announced a subsidy program, set for summer 2027, for companies that purchase "smart" devices for their workers. The CSIF and UGT unions are already recommending the wristbands as a complement to existing protective measures: hydration schedules, cooled spaces, and shortened shifts during the hottest hours.

Canaria+ wristbands are sold by Spanish suppliers of protective equipment, such as the company PGC. Wristbands like these cost between 40 and 60 euros. There are rechargeable models — they last for around 500 charging cycles of 480 hours each and trigger when body temperature exceeds 37.8 degrees or air temperature exceeds 42 degrees. Disposable versions last around five months. They use the person's baseline body temperature and give light, vibration, and sound alerts when a sudden rise is detected.