Anxiety is real, common, and often exactly what it looks like. But "anxiety" is also a symptom, racing thoughts, a pounding heart, restlessness, a knot in the stomach, trouble sleeping, and a number of physical conditions produce those same sensations. When the body sets off the alarm, the mind often looks for a reason and lands on worry, even when the trigger actually started somewhere below the neck.
This matters because a physical contributor that goes unrecognized can keep anxiety going no matter how much therapy or medication is added. At Sphosh Health, part of a careful workup is asking a simple question: is this anxiety, something physical wearing anxiety's clothing, or both? Here are the physical causes most worth ruling out.
Why the body can feel like anxiety
Many anxiety symptoms are, mechanically, the effects of adrenaline and a revved-up nervous system: a fast heartbeat, shallow breathing, sweating, trembling, a sense of dread. Anything that pushes the body into that state, or mimics it, can feel indistinguishable from a panic attack or generalized anxiety. That is why the checklist below is worth a look before concluding the problem is purely psychological.
Common physical contributors worth checking
Thyroid imbalance
An overactive thyroid is a classic anxiety mimic, it can cause a racing heart, restlessness, tremor, heat intolerance and insomnia. An underactive thyroid can drive the low mood and fatigue that often get read as depression. A simple blood panel can flag either one.
Blood-sugar swings
When blood sugar drops, the body releases adrenaline to correct it, and adrenaline feels like anxiety: shakiness, irritability, a pounding heart, sudden dread, often a few hours after eating or when meals are skipped. People who ride blood-sugar roller coasters frequently describe "anxiety attacks" that track with their eating patterns.
Caffeine, stimulants and certain medications
Caffeine is a stimulant that directly raises the body's arousal, and sensitivity varies enormously from person to person. Some medications, decongestants and supplements can do the same. Sometimes the most useful "anxiety treatment" is simply identifying what is quietly overstimulating the system.
Nutrient deficiencies
Low levels of certain nutrients, magnesium, vitamin B12, vitamin D and iron among them, are associated with anxiety and mood symptoms. They are common, easy to test for, and often straightforward to address.
Hormonal shifts
Hormonal changes across the menstrual cycle, in the perimenopausal years, postpartum, or with thyroid and adrenal function can all amplify anxiety. Anxiety that arrives on a predictable schedule is a clue worth following.
Sleep problems
Poor sleep and anxiety feed each other. Sleep apnea in particular can fragment the night, raise stress hormones, and produce daytime anxiety and morning dread, often without the person realizing their sleep is the problem.
Gut and inflammation
The gut and brain are in constant communication, and gut disturbances and chronic inflammation are increasingly linked to anxiety and mood. We explore this more in The Gut-Brain Connection.
How to tell the difference
A few patterns make a physical contributor more likely, none are proof, but each is a reason to look:
- The anxiety came on suddenly, with no clear life stressor behind it.
- It tracks with eating, your cycle, sleep, or a new medication or supplement.
- Physical symptoms, racing heart, tremor, heat, weight changes, lead, and the worry follows.
- It started later in life, or changed character noticeably.
- Standard anxiety treatment has helped only partially, despite a fair trial.
None of this means the anxiety "isn't real" or is "all physical." Very often it is both, a physical trigger and a genuine anxiety response that has taken on a life of its own. The point of ruling physical causes in or out is simply to treat everything that is actually driving it.
What a thorough workup looks like
Ruling these in or out does not require testing everything under the sun. It starts with a careful history, when the anxiety happens, what it tracks with, your health background, and then targeted testing where the story points. Thyroid, blood sugar, key nutrients and hormones are common, high-yield places to look. You can read more about how we approach functional medicine testing and, more broadly, natural, root-cause anxiety treatment.
The goal isn't to replace mental health care with lab work, it is to make sure that when we treat anxiety, we are treating all of what is causing it.
This article is for general education and is not medical advice. If you have severe, sudden physical symptoms, chest pain, fainting, or a very fast or irregular heartbeat, seek medical care promptly. If you are in crisis, call or text 988.