VTT’s spinout, HTM Solutions announces new non-invasive vital sign monitoring technology to protect firefighters in hostile conditions

News, Press release

The new model is the first to accurately calculate and deliver a wide range of thermal parameter values based solely on heart rate and individual body composition measurements without thermometers or intrusive body probes.

VTT has announced that their Human Thermal Model team HTM Solutions has successfully deployed a new version of their Cee° application using  the Human Thermal Model (HTM) which remotely monitors vital signs of multiple firefighters in real time. In firefighting, elevated core temperature and dehydration can lead to death, making monitoring critical to safety both in training and real emergency situations. 

In cooperation with Emergency Services Academy Finland, HTM’s technology is the first to be able to deliver advanced thermal body parameter values without invasive probes, special pills, or direct body temperature measurement. This greatly reduces the cost of monitoring people working in challenging or hostile conditions.

“Firefighters need to know that their body temperature has not gone too high and this is particularly hard to tell in stressful conditions where firefighters are used to pushing through discomfort,” says Pekka Tuomaala, Principal Scientist at VTT. “Training and exercising while wearing heavy firefighter gear first impacts cognitive skills and then eventually kills you if you are not made aware of your condition. The ultimate human limit is 40 degrees Celsius and legislation says that 38.5 degrees is the maximum allowed for this dangerous work in most cases.”

According to the 2023 Global Climate Report from January to July the global surface temperature ranked third warmest in the 174-year record. These rises in temperature lead to longer and more active fire seasons which leads to an increasing necessity for  active firefighters. In the US alone, there are 32,000 firefighters. In 2021, overexertion, stress and medical issues accounted for 57% of firefighter deaths in the US.

HTM technology delivers a wide range of information, including, but not limited to, body core temperature, sweating rate, and Physiological Strain Index. HTM estimates these vital signs using only individual body composition, such as height and weight, and non-invasive case dependent information – most importantly remotely monitored heart rate – as input data.

Emergency Services Academy Finland is responsible for the education, best practices, and training of new firefighters in Finland. Prior to working with HTM Solutions, firefighter students were required to swallow a pill to monitor their body core temperature during training.

“We were considering ways to measure the core temperature of emergency situation students in real-time and without inserting uncomfortable measurement devices into the body,” said Pekka Lindholm, Head of Training at Emergency Services Academy Finland. “VTT had already done testing with our students using the HTM model and a comparison of the consistency of the results of this model against the result given by the pills swallowed or inserted into the body. I reached out and was excited to find out about the advancements in the technology implementation. The new system enables the monitoring of multiple firefighter students from a single smart tablet without the use of expensive and less pleasant pills.”

Dehydration is also a major problem for firefighters in dangerous conditions and needs to be monitored carefully.

“It causes fatigue and loss of cognitive function,” Tuomaala points out. “Loss of fluid is as potent as drinking shots of vodka. If you lose 10% of your body mass in water, the body goes into shock. Problems start when the body loses 5% or more.”

The benefits of the technology from HTM Solutions for firefighters has now opened the door to other critical and non-critical uses of HTM.

“Wherever there is a need to monitor physical condition and health, core temperature is the most important indicator,” says Harri Lehti, CEO of HTM Solutions. “With HTM software, we can non-invasively monitor core temperature online and in real-time. People working in hostile conditions and athletes can all benefit from less invasive and less expensive monitoring options.”

“No extra hardware is key. The beauty of using a software only model is that there are so many hardware options that measure heart rate and applications we believe HTM can help,” Lehti added. “Today, information is easily gathered from today’s wearables like rings, watches, and chest strap heart rate monitors.”

The project has been part of VTT LaunchPad, a science-based spin-off incubator, where VTT researchers and technology are brought together with the best business minds and investors out there to renew industries. VTT LaunchPad supports incubator teams to develop VTT-owned IPR into fundable spin-off companies.


Further information

HTM Solutions Oy
Harri Lehti, CEO
tel. +358 50 444 2928, [email protected]

VTT Technical Research Centre of Finland Ltd
Pekka Tuomaala, Principal Scientist
tel. +358 40 720 1724, [email protected] 

HTM Solutions Oy

HTM Solutions, a spin-out company from VTT Technical Research Centre of Finland, offers a new option for monitoring human thermal status of individuals in real time. We bring peace of mind to people suffering from extreme thermal conditions in various sectors, such as occupational health, sports, and intelligent buildings. As non-invasive and digital solution, HTM technology improves peoples’ wellbeing and productivity - whenever thermal satisfaction, safety, or security is an issue.

Pekka Tuomaala
Pekka Tuomaala
Principal Scientist
Lotta Partanen
Lotta Partanen
Our vision beyond 2030

Heart rate monitors and smart watches are just the beginning. What if, in addition to your pulse, your smart device were able to tell you the right time to take a sip of your sports drink so that you could ride your bicycle longer?