IFA 2026: Speediance Strap puts core body temperature on your wrist

Another screenless fitness band? Yep, and normally that would not be enough to get terribly excited about. The Speediance Strap has one feature that made me stop and look at IFA 2026, though: it uses greenteg sensor technology to estimate core body temperature from the wrist.

Doing something different

Plenty of wearables already track temperature, but most report changes at the skin rather than the temperature inside the body. Speediance says its first wearable will track core body temperature continuously, using technology supplied by Swiss thermal-sensing specialist greenteg.

The underlying CALERA system combines a skin-temperature sensor with a heat-flux sensor, which measures thermal energy moving out of the body. An algorithm then uses those signals to calculate an estimated core temperature, avoiding the invasive methods traditionally used in sport and research.

Core temperature can show how your body is responding as a session unfolds. Tracked over time, its daily rhythm can also reveal when your body is naturally best prepared to train.

It is not just a temperature band

Like its competition, the screenless tracker is being built around training, sleep, stress and recovery. It is designed to combine those signals into a daily readiness view, then suggest how hard to train and when to take things easier.

The exercise side sounds more ambitious than basic activity tracking. Speediance says the Strap will support endurance and strength sessions, recognise exercises and track movement patterns, training volume and velocity trends. The aim is to estimate changes in strength capacity and fatigue rather than simply count workouts.

That puts it in the same broad category as WHOOP, Polar Loop and the growing number of discreet bands covered in our screenless fitness tracker comparison. The temperature system is the obvious differentiator, while Speediance’s background in connected strength equipment gives it a potentially useful route into workout data that general-purpose wearables often handle poorly.

Speediance says the main activity and recovery data will be available without an additional charge. More advanced AI planning and longer-term analysis will sit inside the optional Wellness+ service. But that kicks in only in the second year, so the first 365 days include all the advanced insights for free.

Launching soon

Speediance first showed the Strap as a prototype at CES in January and said it planned a Kickstarter campaign for the spring, with Standard and Pro versions to follow. By the time of its FIBO appearance in April, the company was still calling it a prototype and said test samples would depend on production progress.

The project has now obviously moved forward. However, Speediance has not confirmed the current price or a retail release date. So those details should remain in the unknown column for now.

The bigger question is whether core temperature changes the daily experience or ends up buried among the usual readiness graphs. If the Strap can measure it consistently and use it to make training advice more specific, Speediance may have found a credible way into a crowded category. I do have a test unit on hand so will be putting this new metric to the test. Look out for my review to come in the near future.