The Tokyo Olympics is battling through a global health crisis but athletes, officials and staff also face another health threat: the heat.
This high-tech AI gadget is one of the organizers' tools to lower the risks of heatstroke.
It is a system developed by Chinese e-commerce giant Alibaba Group.
Staff at 14 venues are using a black earpiece that sends heart rate and body temperature measurements to the cloud where heatstroke risks are evaluated by an algorithm combining individual data and environmental factors.
The system sends alerts to those at high risk of heatstroke through an app, with recommended precautions such as taking a rest and drinking more water.
This is a Tokyo 2020 volunteer who guides Olympic participants at the National Stadium:
"The app presents alerts of 'warnings' and 'severe warnings' even when I haven't noticed heatstroke symptoms myself. So when I saw it on my phone screen, I started to realise the risks of getting heatstroke. I think it's useful in terms of heatstroke prevention."
Alibaba Cloud, a global Olympic partner, said it has been working with organizers for years to launch the device.
Selina Yuan is the general manager of the international business unit at the company:
"For the future, we are going to have the joint efforts with the Olympics organisers together, to really base on the different scenarios and take care (of things) more like how to make the things, you know, more efficient, more convenient for the Olympic Games and even the other sports events."
A study last year by a Games adviser anaylzed data from 1984.
It found that Tokyo had the highest average temperature and precipitation of any host city for the period the Olympics were held.