Welcome back to Healthy Innovations! 👋

I came across a CNN clip on Instagram this week showing pets and babies in China being given huge winter melons to hug during a heatwave. The idea is simple: the melon’s high thermal mass helps draw heat away from the body, like a natural cold pack. It’s a reminder that people have been improvising cooling solutions long before wearables and sensors.

This week’s Deep Dive looks at where that same instinct has landed in 2026: monitoring and cooling tech designed for the people who bear the brunt of extreme heat.

Let's dive in!

Dina Gazzella is 85 and lives alone in the eastern outskirts of Rome. Her husband died in 2023, her cat a year after that, and this summer she has spent it inside a heatwave that pushed the city into the high 30s Celsius (100s Fahrenheit). On her wrist is a small black band that tracks her heart rate and sleep, senses if she falls, and lets her call for help with one press. "If I feel unwell, this is a lifesaver," she told Reuters.

Gazzella is one of around 700 elderly Romans enrolled in a municipal monitoring scheme, now being tested for real: the World Health Organization has linked more than 1,300 excess deaths since June 21 to this summer's heat across Europe. Heat does not announce itself the way a stroke does. It builds quietly, and by the time symptoms are obvious, the window to intervene has often already closed.

Generic heat warnings tell a population to stay indoors and drink water. They say nothing about which specific person, on which specific afternoon, is closest to the edge. A growing and increasingly inventive field of wearables, sensors, fabrics, and pills is starting to answer that question directly, for the three groups who carry the heaviest burden: older adults, outdoor workers, and children in sport.

Rome's bracelet scheme was built for exactly this, funded through EU post-COVID recovery money and rolled out last year to reach isolated older residents. Clinical psychologist Piera Pomente, who runs the program's support desk, says older people's blood pressure and heart rate can shift in ways that look deceptively mild before turning serious in extreme heat. The bracelet has already triggered two emergency responses over the past year.

Similar approaches are emerging elsewhere:

None of this replaces a fan or an air conditioner. It replaces the assumption that someone will notice in time.

Japan has moved fastest on outdoor workers. After workplace heatstroke cases hit a record high, the government amended its industrial safety ordinance in June 2025, requiring employers to act once conditions cross a set heat threshold:

A 2025 German scoping review found these tools reduce risk, but only where a safety culture already exists to act on the alerts. The sensor can flag danger. It cannot make a supervisor listen.

The same instinct, cooling people directly rather than just alerting them, is showing up in materials science.

Researchers have built a laminated "cooling skin" inspired by polar bear fur, which reflects sunlight while letting heat escape from the black skin beneath it. The bioinspired fabric reflects around 96% of incoming sunlight and is still lab-stage, but points toward future protective clothing that cools its wearer passively, with no battery and no app.

Heat illness is the leading preventable cause of death among high school athletes in the United States, and the risk is not evenly spread. Some players run hotter than others under identical conditions, particularly in humid states with football pads trapping the heat sweat is trying to release.

Dr. Cory Coehoorn at LSU Health Shreveport is building a system to catch that variation individually, rather than pulling an entire team off at a fixed temperature. Around 100 high school football players across four Louisiana cities wear upper-arm sensors feeding a machine learning model, designed to flag one overheating player to coaches on a tablet before symptoms appear. "If we can individually monitor these people, we eliminate the chance of them getting to a detrimental state," Coehoorn said.

A gold standard already exists, and it looks nothing like a wearable. NASA's CorTemp capsule, a swallowable pill built to monitor astronauts (John Glenn took one at 77, aboard the 1998 Discovery mission), radios core temperature from inside the digestive tract for up to 30 hours, and has been used on NFL sidelines and by firefighters for two decades.

Treatment is getting inventive too, for when prevention fails.

RhinoChill, built for cardiac arrest patients, sprays an evaporating coolant into the nasal cavity, cooling the brain directly through the base of the skull. Used off-label on genuine heatstroke cases, a 2020 case report describes an 80-year-old patient whose core temperature fell 2.8 degrees Celsius an hour once it was applied, after standard cooling had barely moved the needle.

That reframes what this technology is actually doing. It is not making heat safer in the abstract. It is catching people whose own biology has stopped warning them, and putting that warning back in the hands of someone who can act: a social worker checking a screen, or a coach pulling a player off the field before he knows he needs it.

Gazzella's bracelet does not change the temperature in Rome, and monitoring devices cannot make a Louisiana August less humid. What they can change is the timing of detection: they surface rising physiological risk sooner, and route that signal to someone who can intervene (a caregiver, supervisor, or coach).

For an 85-year-old living alone, or a 16-year-old on the sports field, the critical interval is often the delay between early heat strain and recognizing it as dangerous. In that sense, the technology adds an additional layer of observation when the body's own warning signs may be late, subtle, or missed.

🎨 Your EKG, now in cartoon form. Scientists have invented an electrode you paint straight onto your skin, and it performs just as well as the sticky kind. Developed by researchers across the US and China, the polymer tracks heart rate, muscle activity, and brain waves accurately even through sweat, and breathes over ten times better than standard medical electrodes in hot weather.

Because it goes on like paint, the team suggests it could be printed with cartoon designs to make long-term monitoring less scary for pediatric patients.

Thank you for reading the Healthy Innovations newsletter!

Keep an eye out for next week’s issue, where I will highlight the healthcare innovations you need to know about.

Have a great week!

Alison ✨

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