Many people have experienced feelings of anxiety at some point in their lives, whether those feelings are due to an important exam or unexpected bad news. For individuals with anxiety disorders, these feelings can turn into recurring thoughts or fears that affect daily life. According to the American Psychological Association, anxiety can also be classified by physical symptoms. Dr. Sai Ashuthan, a consultant psychiatrist at Cygnet Health Care in the UK, stated that most of these symptoms result from the excessive production of stress hormones, including cortisol, adrenaline, noradrenaline, and vasopressin. These hormones activate the body's fight-or-flight response, leading to symptoms such as an increased heart rate, sweating, and rapid breathing.
Experts have identified some of the most common physical symptoms of anxiety and the underlying mechanisms behind them:
**Headaches**
Migraines and chronic daily headaches are common among people with anxiety disorders, according to the Anxiety and Depression Association of America. Ashuthan noted that the most common type of headache is tension headache, where the individual feels as if a tight band is around their head. Dr. Anup Mathew, the lead psychiatrist at the Kantaraj Clinic in the UK, explained that headaches can occur due to the release of stress hormones that can constrict blood vessels in the brain. However, it is often difficult to determine which comes first: anxiety or headache. Ashuthan stated, "Headaches can be part of anxiety symptoms, or headaches can actually lead to anxiety."
**Cardiovascular Symptoms**
People with anxiety often report cardiovascular symptoms, such as chest tightness or palpitations. Mathew stated that the reason for this is that stress hormones can cause blood vessels to constrict, leading to an increase in blood pressure and heart rate. Anxiety disorders have also been linked to poor vagus nerve function—the fast track that carries information between the brain and internal organs— and reduced heart rate variability (HRV)—the changes in time between heartbeats—according to a review published in *Frontiers in Psychiatry*. The vagus nerve plays a central role in regulating heart activity: when it does not function properly, it can lead to heart failure in effective contraction. The review's researchers wrote that reduced HRV also predisposes an individual to a slower recovery from stress.
**Gastrointestinal Symptoms**
Ashuthan explained that when an individual is anxious, more stress hormones enter the digestive system. This can lead to gastrointestinal issues such as bloating, abdominal pain, nausea, and constipation. The link between anxiety and visceral hypersensitivity (the low pain threshold in internal organs) may be due to a combination of genetic factors and early life experiences, according to a review published in *Frontiers in Systems Neuroscience*. Early childhood is a pivotal period for the development of brain circuits responsible for regulating stress and pain. Certain genetic variations can increase the risk of these brain circuits not developing properly. When a genetically predisposed individual experiences early life events, such as trauma or abuse, their pain-related neural circuits may develop in a way that enhances feelings of pain and anxiety in adulthood.
Mathew mentioned that stress hormones can also disrupt the balance of gut bacteria, leading to inflammation and other digestive issues. A review published in 2021 in *Clinical Psychology Review* found that people with anxiety disorders tend to have more pro-inflammatory bacteria (such as *Enterobacteriaceae* and *Desulfovibrio*) and fewer beneficial bacteria (like *Faecalibacterium*).
**Weakened Immunity**
Ashuthan indicated that cortisol, which is produced excessively during periods of anxiety, can affect the immune system by disrupting the production of infection-fighting white blood cells. He noted, "Continuous cortisol release will consequently increase the chances of infection."
**Breathing Problems and Dizziness**
Clinical psychologist Angel Enrique from SilverCloud remote health services highlighted that rapid, shallow breathing and dizziness are common symptoms of anxiety. He explained, "We feel anxious when we anticipate that something bad may happen, and the body reacts to help us cope with a severe or stressful situation. This results in a fight-or-flight response. The body responds by increasing our breathing so that our lungs transport more oxygen in case we need to escape." However, Enrique noted that this can make people feel short of breath, potentially leading to further anxiety or panic. Increased breathing rates can also cause dizziness. He stated, "When we feel anxious, we start to breathe quickly and deeply. This leads to decreased carbon dioxide levels in the blood, which can cause nausea, dizziness, or tingling in the hands or feet."
