ble_app_hrs_c how to add 1 sec timer and goto sleep mode?

It's battery operation so I want to know how to setup 1sec timer and goto sleep_mode(power_down) after 1sec beacon scanning.

I'm using WDT to setup 60sec WDT reset so I want to scan only 1sec then goto sleep mode for 59sec to save battery lifetime.

Currently it works fine.

Power_on_reset

WDT setup to 60sec.

scanning for 60sec.

WDT_reset

scanning for 60sec.

WDT_reset

so on.....repeated

I want to know how to setup additional 1sec. timer and after 1sec. scanning, device goto sleep mode for 59sec.

I'm using S130 softdevice, ble_app_hrs_c and nRF51_SDK_9.0.0