- Lindsey Dalton
- February 23, 2025
Your Body’s Morning Alarm: Understanding the Cortisol Awakening Response
Have you ever wondered why some mornings you feel unstoppable, while others struggle from the start? The answer might lie in your cortisol awakening response (CAR), a key part of how your body prepares for the day. While cortisol is commonly known as the “stress hormone” it also helps regulate metabolism, blood sugar, the immune system, and circadian rhythm. Let’s dive deeper into CAR, how it affects our health, and what we can do to manage it.
What is Cortisol Awakening Response?
CAR is a part of our natural circadian rhythm, or sleep/wake cycle. However an important piece of information to keep in mind is that CAR differs from general cortisol levels throughout the day. For example, in a healthy individual, CAR causes cortisol to peak 30-45 minutes after waking, and gradually declines throughout the day. It prepares our body for the day ahead, much like a morning espresso shot helping us feel alert and ready to tackle our tasks. However, when CAR becomes dysregulated, it can signal underlying stress or health challenges.1
The Impact of Stress
Research shows that CAR is heavily influenced by stress. A high level of CAR often indicates chronic stress or a demanding lifestyle. When CAR remains elevated for prolonged periods, it contributes to increased vascular resistance and blood pressure leading to hypertension. Systemic inflammation can also lead to metabolic dysfunction by increasing glucose levels and promoting insulin resistance.1,4 Conversely, a low CAR may be linked to burnout, chronic fatigue, or HPA axis dysfunction leading to symptoms such as brain fog, low energy upon waking, and poor stress tolerance. This is due to adrenal fatigue, where the body struggles to produce adequate cortisol levels after prolonged stress.3,5 Understanding whether your CAR is elevated or decreased can guide targeted interventions to improve your stress resilience and overall health. Here is an overview of how elevated or decreased levels of CAR can impact our health
Elevated CAR
Mechanism: High CAR can lead to stress-induced inflammation and weaken the immune system.5
Symptoms: difficulty relaxing, trouble sleeping, and feeling “on edge”
Chronic Impact: anxiety, depression,chronic inflammation, cardiovascular disease, metabolic disorders, and sleep disturbances.1,2
Decreased CAR
Mechanism: Decreased CAR may result from burnout, disrupted sleep, or nutrient deficiencies.3,5
Symptoms: morning grogginess, inability to focus, and persistent fatigue.3
Chronic Impact: reduced cognitive function, chronic fatigue, and poor stress resilience.
What You Can Do to Regulate Your Cortisol Awakening Response:
If CAR is Elevated:4,5
Practice mindfulness techniques such as meditation or breathing exercises. Mindfulness techniques like diaphragmatic breathing can be practiced for 5 minutes before bed to help calm the nervous system.
Establish a calming nighttime routine to reduce evening stress.
Limit caffeine and other stimulants in the evening.
Consider adaptogens like ashwagandha, that help to support the stress response
If CAR is Decreased:3,5
Improve sleep hygiene by maintaining a consistent sleep schedule and creating a dark, quiet sleep environment.
Expose yourself to bright, full spectrum light in the morning to signal wakefulness. Morning walks in sunlight can naturally stimulate cortisol production and align the circadian rhythm.
Evaluate nutrient levels such as magnesium and vitamin C, and consider supplementation under guidance of a healthcare provider. Eating a protein-rich breakfast shortly after waking can help stabilize energy levels and support a health cortisol response as well.
How is Cortisol Awakening Response Measured?
CAR can be assessed through salivary cortisol tests taken at specific intervals after waking. Understanding your CAR through testing can help provide early insights into stress-related health risks, helping you take action before chronic issues develop.
At-home saliva collection kits are available, and can be paired with laboratory analysis to provide actionable data for patients and clinicians.3,4 If you suspect chronic stress may be affecting your CAR, a healthcare provider can guide you through testing and personalized strategies.
While salivary cortisol testing is a reliable and non-invasive method, it can be influenced by external factors such as sample timing, stress during collection, or irregular sleep patterns. Future research could focus on refining testing protocols to improve accuracy and applicability in diverse populations.
The Final Takeaway:
Your cortisol awakening response offers a unique view into how your body handles stress and prepares you for the day ahead. While genetics can play a role, your daily habits and choices have a powerful influence on its regulation. If your CAR is too high, too low, or somewhere in between- understanding it can help you take proactive steps to support your mental and physical well-being.
Small but meaningful lifestyle changes-like prioritizing sleep quality, managing stress with mindfulness practices, and starting your day with natural light can make a big difference in optimizing your CAR. Testing your CAR under the guidance of a healthcare provider can provide personalized insights, helping you uncover actionable steps to align your stress response with your overall health goals.
Remember, empowering your body to adapt to stress starts with understanding how it responds. If you are concerned how your CAR may be affecting you, you can always schedule a free 15 minute discovery call with one of our practitioners.
Written by Sydnee Payer, PharmD Candidate
Edited by Lindsey Dalton, PharmD
References:
- Clow A, Hucklebridge F, Stalder T, Evans P, Thorn L. The cortisol awakening response: More than a measure of HPA axis function. Neuroscience & Biobehavioral Reviews. 2009;35(1):97-103. doi:https://doi.org/10.1016/j.neubiorev.2009.12.011
- Adam EK, Heissel JA, Zeiders KH, et al. Developmental histories of perceived racial discrimination and diurnal cortisol profiles in adulthood: A 20-year prospective study. Psychoneuroendocrinology. 2015;62:279-291.
doi:https://doi.org/10.1016/j.psyneuen.2015.08.018 - Kudielka BM, Kirschbaum C. Awakening cortisol responses are influenced by health status and awakening time but not by menstrual cycle phase. Psychoneuroendocrinology. 2003;28(1):35-4.doi:https://doi.org/10.1016/s0306- 4530(02)00008-2
- Powell DJ, Wolff Schlotz. Daily Life Stress and the Cortisol Awakening Response: Testing the Anticipation Hypothesis. PLoS ONE. 2012;7(12):e52067-e52067.
doi:https://doi.org/10.1371/journal.pone.0052067 - Chrousos GP. Stress and disorders of the stress system. Nature Reviews Endocrinology. 2009;5(7):374-381. doi:https://doi.org/10.1038/nrendo.2009.106
Dr. Dalton’s areas of focus include disease state management, medication therapy management, and health/wellness coaching. She is a Whole30 Certified Coach, and is passionate about helping people improve their lives through lifestyle modifications. She has seen first hand how changing food alone can vastly improve your health.