Cortisol, stress and sleep training, Is there a connection?
Elevated cortisol, stress and sleep training. Is there really a connection?
Here’s the lowdown on infant stress and cortisol levels during sleep training. Is there a connection between elevated cortisol levels in crying infants during sleep training? Let’s find out.
Firstly, What is cortisol?
Cortisol is a hormone naturally released from your adrenal glands, which are triangle-shaped organs that sit at the top of your kidneys. Cortisol has many different functions in the body and plays an important role in a number of things your body does. Cortisol is your body’s stress hormone, as it’s widely known, but it's use is not only in order to regulate stress in the body.
Here are other main functions cortisol has:
Regulates your body's stress response, mood and fear
Regulates metabolism
Helps reduce inflammation
Helps control your sleep/wake cycles
Regulates blood pressure
Regulates blood sugar
It’s important to know that your cortisol levels normally increase at times of stress and your body needs a balanced amount of cortisol to remain healthy. Not too much and not too little. Now that you have a basic understanding of what cortisol is, we can discuss it in regards to sleep training.
Here is what you need to know
Some studies show a small rise in cortisol in babies while crying during sleep training, but research concludes that there is no adverse long term side effects. There have been many studies done on this and research shows that not all babies even had elevated cortisol levels while crying.
A New Zealand study was done on babies who had undergone sleep training in a sleep lab where it was reported that their cortisol levels were indeed elevated. It was concluded that the rise in cortisol was due to the strange and unfamiliar environment which was obviously stressful for the babies. Interestingly, cortisol levels were much lower in babies who were sleep trained in their own home. You can read more on the study and about stress during sleep training here.
Where does this fear come from?
The basic idea is that crying is stressful for babies, so their brains will flood their bodies with cortisol – the stress hormone – which causes long-term damage to the brain itself, plus a number of other issues leading to unhealthy attachments and psychological disorders
The fear of cortisol spiking during sleep training comes comes from the Sears doctors who claimed (and you can read it here if you are interested) that leaving a baby to cry-it-out is a stressful event that floods their brains with cortisol and can hinder and interfere with healthy brain development causing chronic stress and trauma. However, a few days of crying during sleep training does not constitute chronic, toxic stress and they took the data they had and totally misconstrued it instilling fear into generations of parents.
The types of stress that have been shown to cause long-term social & emotional, behavioral and developmental problems in children are those who experience sustained physical and emotional abuse, who are neglected throughout infancy and childhood, not children who come from loving, positive and stable environments who have their emotional and physical needs met.
Stress and cortisol During sleep training
There is no research or evidence to support the claim that all forms of crying lead to a rise in elevated cortisol levels. Babies can experience a rise in cortisol with any new change or activity. It's important to remember that there are different kinds of stress, too, acute, traumatic and chronic and they're not all bad or one in the same, and the stress discussed here in regards to sleep training is acute stress.
Studies have actually found that the levels of cortisol a baby releases during times of short term "stress" are actually lower (by 100-200%) than the cortisol levels babies naturally produce throughout the course of each day. Cortisol levels have also been found to be far higher in babies and children who are overtired, than those who experience some form of sleep training.
Babies respond to different forms of stress and it so happens to be that not all crying leads to a rise in cortisol levels. Studies have found that the amount of cortisol a baby releases during times of short term "stress" are far lower than cortisol levels babies naturally produce throughout a 24 hour period.
Interestingly, cortisol levels have also been found to be far higher in babies and children who are overtired and who do not sleep well, than those who undergo any form of sleep training. Researchers have found higher levels of cortisol and a more sustained stress response in children starting daycare than in children during a few days of sleep training. This stress was measured with babies who underwent traditional cry-it-out methods.
Babies and children will naturally experience a rise in cortisol with any new experience, major change or event. For example, bringing home a new baby, starting school, meeting a new person, giving a newborn a bath or a trip to the Dr. These events can all trigger stress responses accompanied with temporary spikes in cortisol. However, After a few days of repetition or exposure to the current stressor, babies stop reacting with a stress response to these events, not because they have given up crying, but because they have learned to move past the stress of the event and experience it as a more positive one. They also become more familiar with their routine and what to expect from each scenario which makes the event itself less stressful.
The bottom line
The cortisol babies have during sleep training is not sustained and not enough to cause any harm to your child, short or long term. The short term stress an infant experiences during sleep training will not cause long term chronic stress, emotional, behavioral, psychological, or attachment issues and you can read more about that here in a post I wrote about what research says about sleep training.
