You can set 2 types of silent alarm on your iHealth Wave:
When the alarm is triggered the iHealth Wave vibrates for few seconds to wake you up in silence or to inform you that you have been inactive for a time that you can set in the app.
To wake you up silently without waking up your spouse, you can set up to 3 different sleep alarms each with a repeat option (from never to daily).
To set up a sleep alarm, launch the app and go to MENU> Set up my devices> Select your iHealth Wave> Sleep Alarm
Alarm of inactivity
The alarm of inactivity allows you to be alerted when you have been inactive for a time that can be set in the app (adjustable in increments of 30 minutes from 30 min to 23:30).
To set up an alarm of inactivity, launch the app and go to MENU> Set up my devices> Select your iHealth Wave> Active Alarm
*credit to Sylvain of iHealth Labs EU