My company uses people safe, it monitors you all the time, so if you lay down for more than 10mins, the alarm is triggered, it is linked to every employee in the company (>900 people) and emergency services, and it takes around 15 minutes response time for someone to get to you once the alarm is triggered.
While you are waiting there is someone on the phone or fob talking to you all the time, and they can override your phone to see you and activate the device you are using.
Very big brother, but have a zero death rate for employees at my work and it is high risk.
How much does that cost please? - it sounds like it would be ideal for the 4x4 response groups where we sending people out on their own in foul weather.