When does the 4 min Egg timer start? Opening app, on the minute, something else?

Title is self-explanatory. Does anyone know when the 4 minute counter starts before the egg distance is updated? Is it some pre-set time (e.g. 5:00pm, 5:04pm, 5:08pm), based on when you load the app, or something else?

If it's based on when you load the app, can reloading the app more frequently (every 30 seconds for example) help you get more distance while traveling faster.