My Jack Russell alerts my husband when I'm low while I'm sleeping. We adopted him from the Humane Society and he has alerted my husband three times..the latest was this morning...I went low while sleeping and Moe was with me in bed for a few hours, he then started to bark, my husband came in Moe was face to face with me..he looked at my husband and then at me and barked again...my husband got me glucose gel and my hero got a treat(the dog not the husband) he got a kiss. I can tell when my blood sugar gets low when I'm awake. He is very protective of me, he barks at my husband when he playfully spanks me, but when I "hit" my husband, Moe pays no attention to him. He's a great dog, we lucked out when we got him.