Can Stress and Anxiety Cause Physical Exhaustion? Yes — Here Is Why

What does stress do to the body physically?

When the brain perceives a threat — whether a real danger or an unrelenting stream of worry — it triggers the stress response. Hormones like adrenaline and cortisol are released, which:

• Raise heart rate and blood pressure to prepare for action
• Tighten muscles throughout the body, especially the neck, shoulders, jaw, and back
• Heighten alertness — useful in an emergency, exhausting when constant
• Divert resources away from digestion, immune function, and cellular repair

In short bursts, this response is healthy. But when stress is chronic — when the signal stays on for weeks or months — the body pays an ongoing energy cost. The nervous system never fully enters rest-and-recovery mode, and that sustained expenditure is felt as exhaustion.

Why is anxiety particularly draining?

Anxiety disorders are among the most prevalent mental health conditions 1Ref 1National Institute of Mental Health (2023).Anxiety Disorders.Prevalence of anxiety disorders and sleep disruption as a core feature of anxiety, and they involve near-constant activation of the brain's threat-detection system even when no real threat exists. The body runs a low-grade emergency response much of the time.

This produces fatigue in overlapping ways:

• Sleep disruption. Racing thoughts at night and early waking are hallmarks of anxiety 1Ref 1National Institute of Mental Health (2023).Anxiety Disorders.Prevalence of anxiety disorders and sleep disruption as a core feature of anxiety. Poor sleep is itself one of the most powerful causes of fatigue, and the two compound each other.
• Muscle tension. Chronically braced muscles use energy continuously and can cause real physical aching alongside fatigue.
• Hyperventilation. Anxious breathing patterns shift the balance of oxygen and carbon dioxide, contributing to dizziness, fatigue, and brain fog.
• Mental load. Worrying is cognitively expensive. Sustained rumination and anticipatory anxiety burn significant energy.
• Cortisol dysregulation. Chronically elevated cortisol can eventually blunt the normal morning cortisol peak that helps people feel alert, so mornings feel as exhausted as evenings.

How can you tell if stress is the main driver of your fatigue?

Stress-related fatigue tends to follow a recognizable pattern. It often:

• Tracks clearly with periods of higher stress (deadlines, conflict, uncertainty)
• Comes with poor sleep, muscle tension, or worry that is hard to switch off
• Includes brain fog or difficulty concentrating
• Improves — at least partially — during genuinely low-stress periods
• Accompanies other physical stress symptoms: headaches, stomach upset, tight jaw or shoulders

If fatigue does not track with stress levels, comes alongside new physical symptoms (weight changes, palpitations, pallor), or does not improve at all with rest, those patterns are worth exploring with a clinician to rule out a medical cause alongside the anxiety.

What actually helps stress-related exhaustion?

The most effective approaches address both the stress response itself and the sleep disruption it creates.

Treating anxiety directly — through cognitive-behavioral therapy (CBT), medication, or both — is often the most direct route to resolving anxiety-driven fatigue. CBT has strong evidence across anxiety disorders and addresses both thought patterns and the behaviors (avoidance, inactivity) that sustain them 2Ref 2Hofmann SG, Asnaani A, Vonk IJJ, Sawyer AT, Fang A (2012).The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses.Evidence base for CBT as an effective treatment for anxiety disorders, which drives resolution of anxiety-related fatigue.

Validated screening tools like the GAD-7 3Ref 3Spitzer RL, Kroenke K, Williams JBW, Löwe B (2006).A Brief Measure for Assessing Generalized Anxiety Disorder: The GAD-7.The GAD-7 as a validated clinical screening tool to quantify anxiety severity and guide treatment decisions help clinicians quantify anxiety severity and guide whether therapy, medication, or a combination is most appropriate.

Sleep hygiene — consistent sleep and wake times, a dark and cool room, limiting screens before bed — helps break the anxiety-disrupts-sleep cycle.

Regular physical movement reduces cortisol, improves sleep quality, and is consistently effective for both anxiety and fatigue.

Breathing practices that activate the parasympathetic nervous system — slow exhalations, diaphragmatic breathing — can reduce the stress response in the moment.

If stress and anxiety are significantly affecting daily life and energy, speaking with a clinician or mental health professional is appropriate. Primary care is a reasonable first stop; they can screen for both anxiety and medical contributors to fatigue.