Home » Feature Story » Wearable Devices » Temple pre-orders may open next week: How Deepinder Goyal’s wearable may be different from smartwatches and rings

Temple pre-orders may open next week: How Deepinder Goyal’s wearable may be different from smartwatches and rings

HIGHLIGHTS

Temple uses a light-based BrainFlow system to monitor blood-flow changes around the temple instead of relying on wrist or finger-based tracking.

Its proprietary Entropy score is designed to reflect changes in physiological load, stress, fatigue and recovery on a scale of 1 to 250.

Expected to cost around Rs 75,000 to Rs 1 lakh, Temple is positioned as a premium wellness device rather than a certified medical wearable.

Temple pre-orders may open next week: How Deepinder Goyal’s wearable may be different from smartwatches and rings
Ashish Singh Ashish Singh
08-Oct-2026

The wearable market has seen a lot of improvement over the years. There are smartwatches that can count steps, measure heart rate and track workouts along with managing your notifications, calls and more, while smart rings have made sleep and recovery monitoring increasingly discreet. But that is not all. The wearable market is seeing a lot of new products including fitness bands. But what I am particularly excited about is the Temple wearable.

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The device has been in the headlines for a while. Backed by Zomato and Eternal founder Deepinder Goyal, Temple is an experimental health-tech wearable designed to sit on the side of your head to monitor changes in blood flow. Then it will use that information to generate a proprietary metric called Entropy, which the company says can provide insights into cognitive load, fatigue, stress and overall physiological demand.

It is said to enter a consumer pre-order phase soon, but how will it exactly differ from the already available smartwatches and smart rings and what exactly it is.

Temple is worn on your head, not your wrist

The most obvious difference is where the Temple sits. As you might have seen in multiple podcasts or social media posts, the wearable is a small pill-shaped module that attaches to the side of the head, around the temple area between the forehead and ear.

There is no watch strap or ring sizing involved. The device is held against the skin using adhesive Grips, which Temple says are designed to remain secure during workouts, showers and swimming. When launched, the company will reportedly ask the users to change the Grip every two to three days for hygiene, particularly for those who sweat heavily.

The device itself is expected to offer around seven days of battery life. It is also designed with smooth edges to reduce the chances of catching on clothing or glasses during everyday use. Temple says the device can be worn while swimming and exercising, although it advises against activities such as scuba diving.

What exactly is Temple trying to measure?

This is where Temple becomes considerably more ambitious than a conventional fitness tracker. Most smartwatches and rings rely heavily on photoplethysmography, or PPG, to measure things such as heart rate and blood oxygen levels. The sensor shines light into the skin and analyses changes in reflected light caused by blood flow.

Temple also reportedly uses a form of PPG technology. However, its sensors are positioned over the superficial temporal artery, rather than on the wrist or finger. The company calls its proprietary sensing and processing system BrainFlow. Temple says its location allows the sensor to observe blood-flow changes closer to the brain and that these signals can provide information that is more closely related to changes in cerebral blood volume than conventional wrist-based measurements.

It is not claiming to simply be another heart-rate or activity tracker. Instead, it wants to turn changes in blood circulation around the head into a continuous measure of the body’s physiological state.

The Entropy score is Temple’s answer to steps and calories

The data collected by Temple is condensed into a proprietary metric called Entropy, which runs from 1 to 250 and updates continuously. According to Temple, lower scores indicate a state of lower physiological demand, while higher scores correspond to increased stress, physical exertion or metabolic activity.

The company describes Entropy as a measure of the body’s real-time cost of being alive. In practical terms, the score is intended to reflect changes in autonomic nervous system activity and overall physiological load.

At the lower end of the scale, scores between 1 and 50 are associated with deep rest and states such as meditation. At the higher end, scores between 150 and 250 can occur during intense exercise or periods of physical or mental stress.

Temple says the score can also respond to things such as caffeine and digestion.

The idea is interesting because it moves away from the familiar wearable metrics we already know. Rather than telling you that you walked 8,000 steps or burned a certain number of calories, Temple wants to provide a continuous picture of how demanding a particular moment is for your body. But it should be noted that Entropy is a proprietary metric, not an established medical measurement. That distinction is important when interpreting what the number actually means.

Temple’s BrainFlow technology is still the biggest question mark

Temple’s claims about BrainFlow are likely to attract as much scrutiny as the device itself. The company says its validation work has compared its measurements with established techniques including transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS).

Temple has also cited research involving a relatively small group of healthy adults and says its measurements showed strong within-person correlations during controlled posture changes. The company has reported a correlation of around 0.8 in those tests.

It has also claimed that Entropy showed a 0.91 correlation with professional metabolic-cart measurements during high-intensity exercise, compared with 0.55 for traditional heart-rate measurements in the same context.

These numbers sound impressive, but correlation does not automatically establish that Temple is directly measuring brain activity or diagnosing anything happening inside the brain.

The device remains a non-invasive optical sensor sitting on the skin. Medical experts have therefore questioned how much information it can obtain about deeper cerebral blood flow, particularly given that the skull and surrounding tissue sit between the sensor and the brain.

How much it may cost?

The biggest surprise can ultimately be the price. Temple is expected to sit somewhere around Rs 75,000 to Rs 1 lakh, putting it well above most premium smartwatches and smart rings.

The company is reportedly taking a different approach to subscriptions as well. Instead of charging users a relatively low hardware price and then locking important features behind a monthly plan, Temple’s premium package is said to be subscription free.

The package is also expected to include the adhesive Grips required to keep the device attached to the skin. This means, almost all parts of the hardware will be covered.

Will it outpower smartwatches and rings?

The company is attempting to turn optical measurements from Temple into a new way of understanding physiological and potentially cognitive states. Its research and validation work may provide useful evidence, but much of the product’s most interesting claims still needs to be researched or tested independently.

For consumers, that means Temple should be viewed as an experimental wellness wearable, not a replacement for established neurological or cardiovascular tests done by experts.

At the same time, it brings some questions: what happens when health tracking stops being about counting what we do and starts trying to understand why our bodies respond the way they do? Personally, this will not change anything about the smartwatches and rings and will be a premium wearable that is used to monitor stress.

Ashish Singh

Ashish Singh

Ashish Singh is the Chief Copy Editor at Digit. He's been wrangling tech jargon since 2020 (Times Internet, Jagran English '22). When not policing commas, he's likely fueling his gadget habit with coffee, strategising his next virtual race, or plotting a road trip to test the latest in-car tech. He speaks fluent Geek. View Full Profile