Temple, a wearable fitness device launched by Zomato founder Deepinder Goyal, has drawn questions from doctors about what its readings can establish. The device is worn at the side of the head with adhesive patches and is priced at Rs 85,000.
Goyal has described Temple as a fitness and artificial-intelligence device. In a post on X, he said it makes no medical claims, is not proven to diagnose or prevent disease, and does not replace medical advice or a visit to a doctor.
Questions about what the device measures
Temple is presented as monitoring blood flow near the head and providing information across several areas of wellbeing. Doctors quoted by The Indian Express cautioned that a signal detected at the temple should not automatically be treated as a direct measurement of blood circulation inside the brain.
Dr Seema Shahi, director and head of neurology at Pacific One Health Hospitals in Delhi, said the brain’s health involves many processes, including neuronal activity, electrical signalling, cognition and communication among nerve cells. She said preliminary comparisons of Temple’s BrainFlow readings with Transcranial Doppler are not enough to establish the wearable as a validated clinical diagnostic tool. Larger, independent studies are needed to assess its accuracy and usefulness, she said.
Dr Abhijeet Gaikwad, a consultant neurologist at Inamdar Multispecialty Hospital in Pune, said readings linked to blood flow near the temporal artery may offer some information about bodily responses, but can be affected by factors such as movement, sensor placement, activity and individual differences. He cautioned against treating one sensor’s output as a complete account of complex processes such as stress, metabolism or physical performance.
Dr Girish Nair, a senior consultant neurologist at Apollo Hospitals in Navi Mumbai, said a light sensor at the temple measures signals from superficial vessels rather than directly examining the brain or its internal blood flow.
Wearable scores are not diagnoses
Doctors also warned against interpreting a wearable’s estimates as evidence that a person has, or does not have, a medical condition. Dr Shahi said a single blood-flow reading cannot predict Alzheimer’s disease, stroke or cognitive decline.
Dr Nair said scores labelled as stress or metabolic recovery are estimates based on physiological signals, not substitutes for investigations such as MRI or EEG. He added that ordinary factors including poor sleep, stress and meals can affect measurements, and that wearable readings should not be used to rule out cardiovascular problems or delay specialist care when symptoms occur.
Dr Mohammed Rehan Sayeed, a cardiothoracic surgeon, said interpreting a wearable signal as a measure of blood flow inside the skull calls for stronger evidence. He said trends in validated measures such as heart rate and heartbeat timing may help people follow responses to training or recovery, but that is different from establishing cerebral blood flow.
Independent evidence remains important
Dr Sayeed said he would want independent studies showing how accurately Temple tracks blood flow inside the skull across different people and everyday conditions. Until then, he said, its BrainFlow score should be treated as an experimental wellness metric rather than used in clinical decisions.
Badminton player PV Sindhu has said she uses Temple while playing and swimming, and described herself as initially doubtful before becoming positive about her experience. Her account is a personal endorsement; it does not establish the device’s clinical accuracy.
The doctors’ central caution is that a wearable can produce physiological readings without those readings amounting to a validated medical test. Goyal, for his part, has said Temple is not intended to diagnose or prevent disease or replace a doctor.
