How to increase the sleep time of interface controller in apple watch app?

I am creating a workout app and when the user creates a workout then a countdown timer is shown. When the watch app is in foreground, then the timer works correct and after 3 seconds the activity screen is shown. But if the Apple Watch sleeps(when I low down the wrist), then after 3 seconds, the new interface controller is not shown. I know that this is because the timer does not run in the background. How does the Apple Watch default workout app handles this? When I create a workout in apple workout app, the Apple Watch does not get to sleep mode during the countdown timer screen. How do they manage this and how can I achieve this in my app so that the user experience is smooth?
How to increase the sleep time of interface controller in apple watch app?
 
 
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