14 In All About Children's Emotions/ All About Your Child's Development/ Child Development/ Parenting Solutions

The Surprising Reason your Child is Suddenly Cranky (and what to do about it!)

why is my child grumpy

There are lots of reasons that kids get cranky — just like us, they have bad days too.  Some of the usual suspects are a lack of sleep, hunger, overstimulation, and the like. The easy fix for those times is to feed them and shuffle them off to bed.

why is my child grumpy

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But what about when the crankiness goes on for days? Those times when your usually happy-go-lucky or laid-backed child turns into a grumpy, whiny, picky, sleepy, overstimulated bundle of emotions.

A likely culprit for all that irritability is a cognitive leap or a growth spurt in the brain — a time when your child is working on a new skill under the surface, in the depths of the brain.

Really this newfound crankiness is simply a symtom of a growth spurt in the brain, otherwise know as a cognitive leap.

What is a Cognitive Leap?

Development rarely, if ever, follows a steady pace of upwards progress. Instead, it is characterized by leaps and spurts, gains and losses, regression and progression, and general disorganization.

Before the new skill is learned and before the brain solidifies new connections, there is a period of relative chaos. After the new skill is mastered and the brain connections solidify equilibrium and your cheery child (and your sanity!) returns. (For my take on leaps in the first two years read this.)

When the brain goes through a growth spurt it is adding new connections and trimming unused ones. Have you ever noticed that when your child is learning a new skill that they practice it over and over?

Practicing these new skills can almost seem like a compulsion. Like when a toddler plays the same scenario over and over and over again. Or when a preschooler starts repeating letter sounds all day. That kind of repetition is indicative that your child is in the midst of a brain growth spurt otherwise know as a cognitive leap.

People are not born once and for all on the day that their mother puts them on to the Earth, but…time and time again, life forces them to enter a new world on their own. – Gabriel Garcia Marquez

Brain Growth Spurts in the Early Years

When the brain is practicing these news skills it is physically changing. New connections between brain fibers are growing, strengthening, or being trimmed away.

During this growth spurts, the brain is disorganized — these new connections may be misfiring and miscommunicating and the brain may shift resources from other parts of the brain to the growing part.

How does this all affect your child’s behavior? In a word, they will be more cranky. 

Growth spurt symptoms are related to immune suppression (and fevers) and sleep regression. And a growing brain is a HUNGRY brain. Even during equilibrium when children are not actively going through a growth spurt, a 5-year-old’s brain uses more glucose than an adult’s bigger brain.

At age 4, the brain uses 43% of the body’s total energy expenditure!

So, your usually regulated and balanced child is getting less quality sleep, needs more fuel for the body and brain, is more sensitive to their surroundings (hence easily overstimulated) and more emotional.

The good news is twofold, first is that in a week or so, your happy child will return and second, you can do a few things to ease the crankiness and support the brain during these leaps.

5 Ways to Support Your Child’s Brain During Cognitive Leaps

1. Head to Bed Early

Earlier than you think — before you would expect for your kids to be tired. I am a huge fan of early bedtimes, in general (for more of the research behind the benefits of early bedtimes, read this) and when a cognitive leap hits, I aim for an even earlier bedtime.

Studies show that the later kids go to sleep, the longer they take to get to sleep and the earlier they wake, the opposite of what the brain needs during this time.

Start with increments of 20 minutes. If your child usually goes to sleep at 8:30, aim for 8:10. Give it a day or so and move to 7:50 and then 7:30. For tips on easing the transition to sleep read this.

Research has shown that when children are sleeping, connections in the brain change. Some weaken (are trimmed) and some get stronger. In one night of sleep, connections between the right and left hemispheres can increase as much as 20%. What children practice and learn during the day, is solidified at night.

2. Eat Healthy Fats

Whenever my son shows signs of a growth spurt, I up the healthy snacks and healthy fats in his food. We often think our kids get plenty of fat– but are they getting the kind of healthy fats the brain is hungry for?

The research on diet and brain is all over the place and I am not a nutritionist. But, several studies point to the importance of  Omega 3s, antioxidants to protect the brain from self-generating free radicals, and iron. Of course, there are other studies which do not show the same effects.

Here are a few links about nutrition and the brain if you are interested in reading further.

Special Fats Proven Essential for Brain Growth

Do Kids Need Omega-3 Fats? from the Academy of Nutrition and Dietetics

Scientists Learn How Food Affects The Brain: Omega 3 Especially Important

Why fish intake by pregnant women improves the growth of a child’s brain

Do omega-3 supplements help the brain? NIH study casts doubt

When my son is going through a leap I give him an Omega-3 supplement. These are my favorites, a multi-vitamin with fish oil and a simple fish oil gummy. I like to vary which I give him, depending on what is on sale.

Instead of the normal cheese crackers and raisins to tide him over until dinner, I stem the hangry attacks with snacks like avocado and fruit smoothies, oatmeal with flax seeds, banana, and nut butter rolled in a multi-grain tortilla, and refried beans and chips.

My son won’t eat fish, he used too and I hope once he is out of this normal picky stage, he will again. If you kids will eat fish, pile on the salmon during these times too.

3. Turn on the MusicDo you need some help with getting your toddler to brush their teeth? Get out the door? Transition from inside to outside play? Trying this playlist! This is a great way to bring play into your parenting!

I think that the pattern and tempo of music can calm the disorganization of the brain during these times. Of course, you don’t want to overdo it — but when your cranky child can’t handle sitting at dinner — turn on some tunes to distract their brain. Something low key, but interesting, that can capture their attention. Here is my playlist for toddlers. 

This is also an awesome way to wake-up your child if they are super cranky in the morning. Create a playlist with a few of their favorite songs from movies.

If all else fails, have a family dance party, a surefire way to reduce stress and get good endorphins flowing for the whole family.

4. Go Outside

Being outside calms the mind, enhances learning and creativity, boosts mood, and can even increase kindness. It is my instant fix for a bad day and it is great for kids going through a growth spurt or a cognitive leap.

When kids are learning new skills a lot of time is spent concentrating  — whether we see it or it is happening under the surface. The perfect break from that kind of intense thinking is big motor movement. Running around, a walk on a trail, letting off steam at the playground — anything that gets them moving in a green space will help dispel their crankiness.

There is also evidence that exercise stimulates brain growth, exactly how is still being researched, but there is pretty convincing evidence that outdoor exercise boosts children’s executive function. 

Executive functions like reasoning, planning, decision-making — are housed in the prefrontal cortex, which is developing across childhood. So, getting outside may have multiple benefits both directly and indirectly (lowers stress) on the developing brain.

5. Engage the Mind: Books, Games, & Sensory Activities

When they are babies it is easy to see what they need to have time practicing — crawling, standing, walking, vowel cooing, and so on. With older kids, the skill they are working on may not be as clear. But there are a few activities that will enhance many different kinds of skills.

When my son hits a cognitive leap and is suddenly cranky I find that doing something with him that engages his mind will also calm him down.

Some of the best activities that will calm a busy, active mind are sensory activities. During leaps, I might make a big batch of play dough or slime. Or gather some toys we don’t usually play with outside and take them in the sandbox. Activities that keep the hands busy, help soothe the over-active mind during big growth spurts.

I pile up a bunch of books from the library near the breakfast table and around the house. These also help occupy growing minds.

We also love playing games in our family and board games are so good for kids developing brains — they challenge kid’s impulse control, reasoning, attention and much more.

Here are my favorites games for self-regulation skills.

So, have some fun, read some good books, listen to some music, drink some healthy smoothies, get some extra sleep, and think to yourself: this too shall pass. Once it’s over they will have grown and learned — and perhaps we will learn and grow a little bit too.


The Science of Development in the First Two Years

A Science-Backed Bedtime Routine

3 Things About Child Development Every Parent Should Know










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  • Ivan Jordon
    July 16, 2016 at 11:19 am

    A cranky child can be annoying.. I should know. I have children that tend to be cranky most of the time.. lol

  • Why You Need to Protect Your Son's Childhood - Nurture and Thrive
    August 24, 2016 at 3:59 pm

    […] The Surprising Reason your Child is Suddenly Cranky (and what to do about it!) […]

  • Alice @ Mums Make Lists
    September 2, 2016 at 4:20 am

    Really interesting read Ashley – I hadn’t thought about the whole fats thing when they’re going through growth spurts but makes sense.

  • Suzanne
    October 12, 2016 at 11:36 pm

    Very informative. I appreciate your clear way of communicating on a complex topic . I also appreciate the suggestions of ways to help the child.. I have signed up for your newsletter.

  • Doctorsahaab
    October 16, 2016 at 5:43 am

    Love your site Ashley

  • McKenzie
    January 5, 2017 at 2:51 pm

    Thanks for the information about children’s developing brains! I found the cognitive leaps to be particularly interesting, and it is so apparent that development is never linear or steady. Thanks again!

    • Ashley Soderlund Ph.D.
      January 8, 2017 at 10:55 am

      Thank you and thanks for leaving some feedback. I do love the concept of development happening in leaps and bounds rather than at a linear and steady pace.

  • ruchi
    January 20, 2017 at 11:03 pm

    Thanks Ashley, I’m relieved, my lo has just turned one and these days is being really difficult. It helps to know why he does this.

    • Ashley Soderlund Ph.D.
      January 22, 2017 at 7:19 am

      Thank you! I always say if things continue unexpectedly it’s always a good idea to check in with you pediatrician to rule out other possibilities.

      Glad the article helped you.

  • Sarah Sutter
    October 16, 2018 at 10:51 am

    This was in my inbox this morning after a very long and disregulated weekend. It was just what I needed! I have been trying to figure out why my kid is over the top cranky lately. She is totally learning to read and is working on different sounds a lot. She is also working on numbers and learning to add them together. Her brain is working extra hard right now and I really need to give her a break about it sometimes. I have found myself picking her up from her stomping on the bed or whatever she’s been asked not to do and just hugging her. Singing songs together has helped the morning routine go more smoothly. Not expecting so much from her at pre-k drop off has been helping too! I’m wondering if some of these cognitive leaps take longer than others. Like reading. It takes so long to learn to read and understand all of the sounds. Couldn’t that take weeks for the brain to process, and mean a much longer period of crankiness?
    Thanks for the the ideas on how to fuel her brain better. I needed that today!

    • Ashley Soderlund Ph.D.
      October 18, 2018 at 9:26 am

      I am so glad it came at a time you really needed it! Thank you for taking the time to leave a comment. And yes, I think some periods of growth can be longer than others. <3