Heart rate variability, or HRV, is a metric often computed by a biofeedback machine to determine the regularity of a heartbeat. It compares the time between each beat, to determine how steady your heart performs.
1 When your baby is getting sleepy, put your baby in his or her crib in a quiet, darkened room. 2  This will help your baby learn to go to sleep in his or her crib. 3  Don't rock your baby to sleep after about age 4 to 6 months. 4  Rock your baby, but lay the baby down to sleep while he or she is drowsy but still awake. Give your baby a bath, sing lullabies, read a book, or tell a story. 2  These activities can help your baby relax. 3  They also signal that it is time to sleep. 4  Don't get your baby excited with active play right before sleep. 5  When your baby is getting sleepy, put your baby in his or her crib in a quiet, darkened room.
According to the theory, if you mix a little bit of rice cereal in with an infantâs formula for the last feeding of the night, the baby will sleep longer because her tummy is fuller. And according to some moms, the cereal is what helps their babies sleep longer.