Both stress and anxiety can disrupt your sleep. They are often cast together due to the fact that they can have similar symptoms and both serve as an adaptive survival mechanism which, if persisting for a long period of time, can become a serious problem.
But what, really, are stress and anxiety?
Stress is a physiological response to an external cause, while anxiety’s origins are more internal, and can therefore persist even after a stressful event has passed.
You may be wondering how stress or anxiety is affecting the quality and quantity of your sleep. Neurobiologically, stress and anxiety are very similar and both are associated with conditions such as depression. However, there are some major differences between the two as well, and can affect your sleep in different ways.
Read on to learn more about stress and anxiety, their similarities and differences, and how they can both affect your ability to get a good night’s sleep.
Please keep in mind that the information presented in this article is informational only and not meant to serve as or replace medical advice, so for help with stress and anxiety, you should consult a doctor or mental health professional.
What is stress?
Stated simply, stress is the body’s reaction to the world’s demands.  Stress is a normal part of life, and our bodies are designed to experience and react to it. The body reacts to environmental changes — both good and bad — via physical, mental, and emotional responses.
What is known as the “stress response” or the “fight or flight response” is activated in times of emergency to mobilize energy resources and help us be more attentive to the environment, and keep us alive.
While people typically think of stress as occurring after negative events such as the loss of a job, a divorce, or an illness, even positive life changes such as a new job or a promotion can be stressful.  Stress can have positive or negative effects in our lives.
Stress is an adaptive mechanism; it keeps us alert and motivated, helping us avoid dangerous situations. However, stress that persists over time can cause some physical symptoms. Common physical symptoms of stress include headaches, upset stomach, excessive worry, muscle tension, increased heart rate, high blood pressure, chest pain, and trouble sleeping. 
If left untreated, chronic stress can have a variety of negative effects on your health. It can cause illness, make certain diseases worse, and bring about emotional problems such as depression, panic attacks, or other anxiety disorders. If you are experiencing chronic stress, you should see a doctor or mental health professional to get treatment and help ensure that your symptoms do not get worse.
What is anxiety?
Like stress, anxiety is a normal part of life, and is part of an innate protective response against danger. Anxiety can work for or against you. For example, the anxiety you feel before taking a test may motivate you to study harder. Anxiety can also help keep you safe, e.g., by helping you perceive threats and avoid dangerous situations, such as walking alone late at night.
However, anxiety becomes a problem when you cannot separate everyday worries from situations which are not threatening. Sometimes, the systems underlying anxiety can become dysregulated. When our anxiety systems are out of whack, this causes us to overreact or react to the wrong situations. 
Like stress, anxiety can also be a longer-term problem. If you are experiencing persistent, excessive fear or worry in situations that are not threatening, you may be dealing with an anxiety disorder. Anxiety disorders are a common mental health issue, affecting about 40 million American adults, or 18% of people aged 18 or older in the United States. In such cases, it is important to seek treatment from a doctor who can help you cope with excessive anxiety.
How do I know if I am experiencing stress, anxiety, or both?
You can use the following short questionnaires as an informal self-assessment of your stress and anxiety. Please keep in mind that these questions are not meant to replace a formal medical assessment, but rather help give you an idea of whether you are dealing with stress, anxiety, or both.
Anxiety is the mind and body’s reaction to stressful, dangerous, or unfamiliar situations. Ask yourself the following questions if you think you may have anxiety:
- Is my anxiety irrational, overwhelming, or out of proportion to the situation?
- Am I having problems sleeping, concentrating, talking to others, or even leaving my home?
- Do I feel like I have no control over my feelings?
- Am I experiencing severe physical problems such as headaches, nausea, or trembling?
- Are these feelings interfering with my daily life?
If you answered yes to any of these questions, you may be dealing with anxiety, but you should talk to your doctor or mental health professional for a professional assessment.
If you think you are dealing with stress, ask yourself the following questions:
- Am I feeling stressed?
- Is there a cause of stress in my life? Find some common causes of stress here. 
- Is my body exhibiting the physical symptoms of stress? You can find 50 common signs and symptoms of stress here.
- Do I find myself resorting to coping mechanisms such as drugs, alcohol, caffeine, or nicotine to deal with life’s challenges?
If you answered yes to any of these questions, you may be dealing with stress. You may wish to discuss your symptoms with a doctor or mental health professional to get proper treatment.
For most people, stress is typically short-lived and situational, and anxiety can be, too. For example, you may feel stress and anxiety preparing for a presentation, but after the presentation is over, so, too, is your source of stress and anxiety.
So, now that we’ve discussed stress and anxiety and their similarities and differences, let’s talk about how they can both affect sleep.
Stress and anxiety are related, but different
As we’ve discussed, there are differences between stress and anxiety. Stress is dependent upon external circumstances, so after a stressor is eliminated, stress levels typically go down. Anxiety, on the other hand, is related to one’s internal state, and can involve worry that may be out of proportion to an event. Even without a stressor present, anxiety may persist, and we may react or overreact to situations which are not necessarily threatening. 
However, as we’ve talked about, stress and anxiety are also related in other ways. Both help us survive by maintaining our alertness and motivation to overcome dangerous situations. Both stress and anxiety can manifest as physical and mental symptoms which interfere with our daily life and our sleep patterns.
How do stress and anxiety affect sleep?
Now that we’ve discussed the similarities and differences between stress and anxiety, we can begin to understand how each of these affects sleep. Stress and anxiety can cause sleep problems or exacerbate existing sleep problems. Over 50% of insomnia cases, for instance, are related to anxiety, depression, or stress. 
Sleep and stress
Stress and sleep are inextricably linked. To manage the effects of external stressors on your life, it is important to boost your resilience to stress. Ways to improve resiliency include eating a healthy diet, exercising regularly, and getting the recommended seven to nine hours of sleep every night. 
This connection between lack of sleep and stress means that not getting enough sleep can cause even more stress. While not all insomnia is a result of stress, people who are under a lot of stress can develop insomnia, so alleviating stress is key to improving stress-related insomnia.
Acute stress induces a sleep-related feature known as REM sleep rebound, which is an increase in rapid eye movement, or REM sleep during the nightly sleep cycles. People experiencing REM sleep rebound may spend more time in REM than during a night of normal, healthy sleep.
While REM sleep rebound typically occurs after a period of sleep deprivation, this sleep phenomenon is also characteristic of those experiencing acute stress. It is thought that REM sleep rebound is an important adaptive feature of sleep in those experiencing acute stress or sleep deprivation as it helps in recovery.
Researchers have also found that acute stress can also affect other phases of sleep, such as slow-wave sleep (SWS). In a review of various sleep studies, researchers found that acute psychological stressors also affected the length of time human participants spent in SWS, although the effects were mixed (of the four total studies investigating SWS, two studies reported a decrease in SWS, while one reported increased SWS, and one study reported no change). 
Increased sleep, and especially Rapid Eye Movement sleep or REM, is critical to recovery from the effects of acute stress. However, scientific studies indicate that people and experimental laboratory animals who have high anxiety benefit less from this innate advantage. 
Chronic stress also affects sleep. While the effects of acute stress can be mitigated by a good night’s sleep, chronic stress impairs sleep and may be a triggering factor for sleep disorders such as insomnia, as well as mood disorders such as depression and anxiety. In a research study conducted at Harvard Medical School, chronic stress caused progressive sleep alterations over time, and impaired the circadian rhythm in laboratory animals.
While some of these alterations and impairments went away after the stressor was eliminated, others seemed to persist and after some time, the laboratory animals showed a sleeping pattern similar to features of depression as observed in humans. 
A limitation of current science in stress research is that the concept of stress is difficult to define, as there are many different types of stress. For example, stress you may feel preparing for an exam is different, in many ways, from stress you exert on your body during a tough workout. Different forms of stressors may be associated with differential effects on sleep, although the exact mechanism by which this occurs remains unclear. 
Stress-related sleep problems, therefore, can lead to a vicious cycle in which sleep deprivation exacerbates stress, which can lead to chronic stress over time. Poor quality sleep, or sleep deprivation, intensifies emotional, behavioral, and stress-related responses. Acute stress and chronic stress have differential effects on sleep. Acute stress can actually be benefitted by sleep, while chronic stress, over time, may cause individuals’ sleep patterns to exhibit features observed in depression. These effects depend, in part, on individuals’ psychobiology (e.g., physiological, genetic, and developmental factors), which makes the sleep-stress connection even more perplexing.
Sleep and Anxiety
Anxiety is one part of the body’s arousal response to stress, whether the stress is real, implied, or overvalued.  Anxiety is part of everyday life for most people, serving as an internal alarm bell to warn us of potential dangers and help us mobilize energy to deal with perceived threats. However, anxiety can make sleeping problems worse, and having an anxiety disorder worsens this problem. Sleep deprivation can contribute to anxiety disorders, transforming the link between sleep and anxiety into a vicious cycle of sleeplessness. Sleep disturbances, especially insomnia, are highly prevalent in sufferers of anxiety, especially patients with anxiety disorders, which are nearly one-fifth of the U.S. adult population. 
In a study conducted at the University of Trondheim and University of Pennsylvania, people reporting insomnia symptoms had significantly higher anxiety. The level of anxiety reported by insomniacs was also correlated with their disrupted sleeping patterns — the more insomnia symptoms the patients reported, the higher their anxiety. While it remains unclear what the sleep profiles are of different anxiety disorders, one thing is clear – the neurobiology of anxiety has implications for sleep physiology.
New research from the University of California, Berkeley, indicates that deep sleep may help calm the overactive, anxious brain.  Specifically, non-Rapid Eye Movement (non-REM) sleep may help the brain process and regulate emotions, and therefore help us better control feelings of anxiety.
What does this all mean?
While stress and anxiety have frequently been cast together due to their similarities, they are different, and each can affect your sleep in different ways. For example, research suggests that stress symptoms can be ameliorated with time spent in REM sleep, while non-REM sleep may be more important for anxiety. Ideally, you should get seven to nine hours of sleep each night so that your brain and body can spend time in all of the different sleep phases. Learn more about a healthy sleep cycle here.
It is important to determine whether your sleep problems stem from stress and/or anxiety or whether they occurred due to a different cause. If you are having sleep problems that you suspect may be due to stress or anxiety, it may be helpful to ask yourself: “Did this sleep problem exist before my stress and anxiety symptoms began, or have I had this sleep problem since before my stress and/or anxiety worsened?”
You may wish to try some relaxation techniques and natural remedies for your stress or anxiety-related sleep problems. Meditation, including guided meditation, can be useful for sleep to reduce stress and provide anxiety relief. relaxation music or essential oils may also be beneficial to promote healthy sleep.
If you cannot achieve better sleep using natural remedies, you may wish to consult with a sleep specialist to help gain insight into the origins of your sleep problems, determine whether they are related to stress and anxiety, and get treatment. Cognitive Behavioral Therapy for Insomnia (CBT-I) is one common treatment option that is used in the context of stress and anxiety-induced insomnia. This behavioral treatment program can teach sleep hygiene tips and address problematic thoughts and behaviors that can interfere with sleep.
Anxiety: A state of excessive uneasiness in response to a perceived threat.
REM Sleep Rebound (REM Rebound): An increase in REM, or Rapid Eye Movement, sleep above normal levels after a period of sleep restriction or deprivation. REM rebound can also occur in people experiencing acute stress.
Stress: The body’s adaptive mechanism which is deployed in response to an external cause (e.g., an adverse or demanding situation).
Stressor: Anything that causes stress.
- “Stress Management: Know your triggers.” Mayo Clinic. Accessible at https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-management/art-20044151.
- “Stress.” Cleveland Clinic. Accessible at https://my.clevelandclinic.org/health/articles/11874-stress.
- “Stress Effects.” The American Institute of Stress. Accessible at https://www.stress.org/stress-effects.
- Coltrera, F. “Anxiety: What it is, what to do.” Accessible at https://www.health.harvard.edu/blog/anxiety-what-it-is-what-to-do-2018060113955.
- “Anxiety Disorders.” National Alliance on Mental Illness. Accessible at https://www.nami.org/learn-more/mental-health-conditions/anxiety-disorders.
- “Causes of Stress.” WebMD. Accessible at https://www.webmd.com/balance/guide/causes-of-stress#1.
- “Sleep Disorders: The Connection Between Sleep And Mental Health.” National Alliance on Mental Illness. Accessible at https://www.nami.org/Learn-More/Mental-Health-Conditions/Related-Conditions/Sleep-Disorders.
- Kim, EJ et al. 2014. “The Effect of Psychosocial Stress on Sleep: A Review of Polysomnographic Evidence.” Behavioral Sleep Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266573.
- Suchecki D, Tiba PA, Machado RB. 2012. “REM Sleep Rebound as an Adaptive Response to Stressful Situations.” Frontiers in Neurology. Accessible at https://www.ncbi.nlm.nih.gov/pubmed/22485105.
- Wells AM et al. 2017. “Effects of Chronic Social Defeat Stress on Sleep and Circadian Rhythms Are Mitigated by Kappa-Opioid Receptor Antagonism.” Journal of Neuroscience. Accessible at https://www.ncbi.nlm.nih.gov/pubmed/28674176.
- Staner L. 2003. “Sleep and anxiety disorders.” Dialogues in Clinical Neuroscience. Accessible at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181635/.
- “Sleep Disorders.” Anxiety and Depression Association of America.” Accessible at https://adaa.org/understanding-anxiety/related-illnesses/sleep-disorders.
- Bragantini D. 2019. “Differences in anxiety levels among symptoms of insomnia. The HUNT study.” Sleep Health. Accessible at https://www.ncbi.nlm.nih.gov/pubmed/31400882.
- Anwar Y, “Chronically anxious? Deep sleep may take the edge off.” Berkeley News. Accessible at https://news.berkeley.edu/2018/11/06/chronically-anxious/.