Crying itself is not bad for babies. It’s their primary way of communicating needs like hunger, discomfort, tiredness, and overstimulation. All babies cry, and the crying follows a predictable developmental pattern that peaks around two months of age and tapers off by five months. What matters is not whether a baby cries, but whether they have a responsive caregiver helping them through it.
How Much Crying Is Normal
Newborns cry more than most new parents expect. Crying typically increases from birth through the first several weeks, peaks around six to eight weeks of age, and gradually decreases by three to five months. During the peak period, some babies cry for five hours a day or longer, even when nothing is wrong. This phase is sometimes called the Period of PURPLE Crying, an acronym pediatricians use to describe its hallmarks: it peaks in the second month, happens unexpectedly, resists soothing, comes with a pain-like facial expression, can be long-lasting, and tends to cluster in the evening.
This pattern is a normal part of neurological development, not a sign that something is wrong with your baby or your parenting. That said, if your baby cries more than three hours a day, more than three days a week, for longer than three weeks, clinicians consider that colic. Colic typically starts around two weeks of age and resolves by three months. It’s worth discussing with your pediatrician, but it’s also not dangerous to the baby.
When Crying Becomes a Problem
The distinction researchers draw is between normal, everyday stress and what Harvard’s Center on the Developing Child calls “toxic stress.” Normal stress, including brief bouts of crying, is actually essential for development. A baby’s heart rate goes up, stress hormones rise slightly, and then everything comes back down. This is healthy. It’s how the stress-response system learns to function properly.
Toxic stress is something different entirely. It occurs when a child experiences strong, frequent, prolonged adversity without supportive relationships to help buffer against it. Think sustained neglect, abuse, or chronic unresponsiveness over weeks and months. Under those conditions, stress hormones stay elevated for extended periods, which can impair the development of neural connections needed for language, attention, and decision-making. Adults who experienced this kind of chronic stress as infants can have abnormal stress reactions later in life and greater vulnerability to social attachment difficulties.
The key variable is not whether the baby cries. It’s whether a caring adult is present and responsive. When a caregiver picks up, soothes, or even just stays close during crying, the baby’s stress activation is “buffered” and returns to baseline quickly. A baby who cries for 20 minutes while you’re trying every soothing technique you know is in a completely different situation from a baby who is routinely ignored for hours.
What the Sleep Training Research Shows
Much of the anxiety around crying comes from the sleep training debate. Parents worry that letting a baby cry during sleep training will damage attachment or cause lasting stress. The research on this is more reassuring than many people expect.
A study published by the American Academy of Pediatrics divided infants into two groups: one that went through sleep training and one that did not. Researchers measured cortisol levels in the babies, parental stress, and attachment style at one year of age. The sleep-trained babies actually showed decreased cortisol levels by the end of the training. There was no difference in attachment security or behavioral problems between the two groups.
This doesn’t mean every form of sleep training is right for every family, but it does suggest that structured, time-limited crying in the context of an otherwise responsive relationship does not cause the kind of harm parents fear. The babies in these studies still had attentive, loving caregivers throughout the day. That consistent responsiveness is what protects development.
The “Strengthens the Lungs” Myth
On the other end of the spectrum, some people claim that crying is actively good for babies because it strengthens their lungs. There’s no evidence for this. Babies who cry a lot don’t develop greater lung capacity than quieter ones. Crying serves a communicative purpose, not a respiratory one.
How to Respond When Your Baby Cries
The healthiest approach is graduated soothing, starting with the least stimulation and working your way up. The AAP-supported CALM Baby Method suggests this progression: start by simply making eye contact with your baby, then talk to them softly, then place a hand on their belly or chest. If that’s not enough, gently hold their arms toward their body or curl their legs up. Try rolling them onto their side (while awake), then pick them up and hold them still before adding rocking. Swaddling, a pacifier, or feeding can come next if earlier steps haven’t worked.
The important detail: try each technique for about five minutes before moving on. That feels like a long time when your baby is screaming, but it gives their nervous system time to process the input and settle. Jumping rapidly from one strategy to another can actually add overstimulation.
Avoid intense soothing techniques like bouncing on an exercise ball. A young baby’s head control may not be strong enough for vigorous movement, and there’s a fall risk.
Why Crying Is So Hard on Parents
If your baby’s crying feels almost physically unbearable, that’s by design. Research published in the Proceedings of the National Academy of Sciences found that infant crying activates a widespread network in the adult brain, including regions involved in emotional processing, movement planning, and threat detection. Mothers show especially pronounced responses in these areas, suggesting the brain treats a baby’s cry as an urgent emotional signal demanding attention.
This wiring is protective. It motivates caregiving. But it also means that prolonged, inconsolable crying can push parents toward frustration and exhaustion. If you reach a point where the crying feels overwhelming, putting your baby down in a safe space like a crib and stepping away for a few minutes is not harmful. A few minutes of crying alone is far safer than being held by a caregiver who has hit their breaking point. That brief pause protects both of you.