Tendinopathy, Stress, and the HPA Axis: What the Evidence Actually Shows

Published Jul 14, 2025Updated Sep 30, 2026Last reviewed Jul 14, 2025

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Tendinopathy rehabilitation works best when the exercise plan fits both the tendon and the person doing it. Progressive loading is central to care, while stress, sleep, confidence and daily demands can affect how someone experiences pain and follows the plan. A cortisol explanation alone cannot determine how quickly a tendon will recover. [1,2]

Tendinopathy describes persistent tendon pain and impaired function related to loading. The Achilles, patellar, shoulder and elbow tendons need different assessments and exercise choices. Begin with the location, the activities that provoke symptoms and the change in function, rather than assuming every painful tendon needs the same heel-drop or stretching routine. [1,3]

What does the HPA axis have to do with tendon pain?

The hypothalamic-pituitary-adrenal axis helps regulate the body's response to stress, including cortisol release. Tendon research often examines glucocorticoid exposure, but the specific experiment matters.

For example, a laboratory study exposed cultured human patellar-tendon cells to dexamethasone. The drug reduced cell proliferation and collagen synthesis under those experimental conditions. Dexamethasone is a synthetic glucocorticoid; exposing cells to it is not a clinical test of everyday psychological stress or a measurement of someone's tendon-healing time. [4]

This distinction changes the practical advice. A person does not need to prove a “normal cortisol curve” before beginning rehabilitation. The useful assessment asks about sleep, mood, work demands, activity and fear of movement alongside tendon strength and function. [1,2]

A 2025 systematic review found greater pain catastrophizing among people with persistent tendinopathy than controls. In lower-limb tendinopathy, anxiety and depression scores were also higher. These findings identify aspects of the recovery experience worth addressing; they do not establish that stress caused the tendon disorder. [2]

Pain can make sleep, work and sport harder, and those disruptions can add stress. The assessment should allow for both directions. Asking about stress is useful when it helps adapt the plan, such as choosing a manageable exercise schedule or addressing fear of reinjury. It should not be used to dismiss the pain.

Can education improve rehabilitation?

In a randomized trial of 66 people with chronic Achilles tendinopathy, both groups completed eight weeks of exercise. One group received pain-science education and the other received education focused on anatomy and pathology. Both groups improved movement-related pain, without a significant advantage for one educational approach. [5]

The trial supports making exercise and symptom management understandable. It does not show that one explanation of pain is a hormone treatment or that stress reduction alone repairs a tendon.

Useful education answers concrete questions: which activities can continue, how much discomfort is acceptable, what to do after a flare, and how to progress. A patient should leave knowing how to carry out the plan, not simply with a list of exercises.

Why does the tendon location change the exercise plan?

Presentation	What the plan needs to account for
Midportion Achilles pain	Progressive calf-tendon loading, tolerance and return to walking, running or jumping
Insertional Achilles pain at the heel	Compression at the insertion, including the effect of deep ankle dorsiflexion
Patellar tendon pain	Knee-extensor loading and the jumping, landing or acceleration demands of the activity
Shoulder or elbow tendon pain	The specific movement, strength deficit and repeated work or sport exposure

The 2024 midportion Achilles guideline recommends tendon-loading exercise as first-line treatment, generally at least three times weekly at an intensity as high as tolerated. It also advises against complete rest as the default and supports activity within tolerance. These recommendations concern diagnosed midportion tendinopathy, not an acute rupture. [1]

Insertional Achilles rehabilitation differs. A 2025 trial randomized 42 sport-active adults to lower- or higher-compression programs. Both used progressive loading, but the lower-compression program limited dorsiflexion, omitted calf stretching and included heel lifts. It produced better pain and function scores at 12 and 24 weeks. [6]

That finding is a reason to tailor the exercise range. It does not mean that every patient should start aggressive heel drops over the edge of a step.

How should sleep and stress fit into the plan?

Identify the practical barrier. Is pain waking you? Is the exercise schedule impossible around shift work? Are you avoiding every activity because you fear damage? Each problem calls for a different adjustment.

For persistent insomnia, the American Academy of Sleep Medicine recommends multicomponent cognitive behavioral therapy for insomnia (CBT-I). Sleep-hygiene tips alone are not its recommended standalone treatment for chronic insomnia. Treating the sleep problem has value in its own right; it should run alongside the tendon plan. [7]

A realistic weekly schedule might include planned loading sessions, an agreed activity level on other days and a brief record of next-day symptoms. Relaxation or psychological support can help someone manage distress and participate in recovery without making a promised percentage improvement in collagen repair the goal.

What role does nutrition play?

Regular meals and adequate protein support a rehabilitation program. Nutrition review is particularly relevant when someone is restricting food, losing weight unintentionally or struggling to eat enough for their activity. It is more useful to identify a specific gap than to prescribe the same supplement stack to every tendon patient.

A frequently cited gelatin study involved eight healthy men, short bouts of rope-skipping and markers of collagen synthesis. It did not measure recovery time in people with tendinopathy. Its laboratory and biomarker findings therefore do not establish a clinical tendon-healing dose of gelatin or vitamin C. [8]

What if an injection is suggested?

Ask which tendon, which preparation, what outcome and what comparison support the recommendation. An injection study in one body region does not establish the same result elsewhere.

In a 240-person trial of chronic midportion Achilles tendinopathy, a single PRP injection did not improve the primary tendon-function outcome at six months compared with a sham procedure. [9] In a separate lateral-elbow trial, corticosteroid injection produced more recurrence at one year than placebo injection, despite its short-term appeal. [10]

Corticosteroid-related tendon rupture is an existing concern in treatment selection. A specialist should consider the target and technique rather than treating repeated injections as a substitute for rehabilitation. [4]

BPC-157 is not an FDA-approved tendon treatment. FDA's current compounding material describes unresolved safety information for the proposed routes. A compounding discussion or advisory-committee recommendation is separate from demonstrating improved tendon outcomes in a controlled clinical trial. [11]

How do you know whether recovery is progressing?

Follow activities that matter: walking distance, heel raises, stairs, gripping, reaching or sport-specific tasks. Record the loading performed, the response later that day and the next morning, and whether capacity is improving over several weeks.

A sudden pop, inability to push off or bear weight, new major weakness, marked swelling, fever or significant injury needs prompt in-person assessment. Those findings should not be managed simply by adjusting a home exercise program. [1]

At routine follow-up, review both the tendon response and the obstacles to following the plan. That makes stress and sleep part of practical care without reducing the entire problem to a cortisol number.