Oculus GO getting a bit hot after a while

There is an issue that started to happen yesterday. In my project, I have an aquarium-like scene. There are different sort of elements and it's supposed to run for at least 15 minutes. After a few minutes, however, the devices starts to get a bit hot and it can be a problem if the user chooses to stay a bit longer than 15 minutes.

I'd like to know if there is a way to improve power consumption and/or if there is something I'm not doing which can help to improve performance.

I'm currently using Unity 2018.2.6f1.

Thanks in advance.