Why Does Your Hip Hurt When You Sleep on Your Side?

Written by the Nuvirox Research Team

Short answer: most likely your gluteal tendons are being compressed against the bone you are lying on — and the top leg is doing more of the damage than the bottom one. Pain over the bony prominence on the outside of the hip, worst when lying on that side and often waking people in the small hours, is a recognised clinical pattern. It was called trochanteric bursitis for decades; the current understanding is that the driver is usually tendinopathy of the gluteus medius and minimus tendons where they attach to the greater trochanter, with compression from the overlying iliotibial band a central part of the mechanism. That reframing matters practically, because it changes what helps. The fair reading is that positioning at night reduces the provocation while graded strengthening does the actual work — and that stretching, the intuitive response, is often counterproductive.

What is actually happening at night?

Side-lying does two things to the hip you are lying on. It presses the greater trochanter — the bony point at the top of the thigh bone — directly into the mattress, compressing the tendons and soft tissue that pass over it. And unless your top leg is supported, it falls forward and across the midline, pulling the underlying hip into adduction.

Adduction is the position that tensions the iliotibial band across the trochanter, which increases the compressive load on the gluteal tendons underneath it. So the hip you are lying on is being squeezed from below by the mattress and from above by the band, for hours, without movement. The clinical literature on gluteal tendinopathy identifies sustained adducted positions — side sleeping, sitting with legs crossed, standing with weight hanging on one hip — as significant contributors to cumulative compressive load.

This also explains the characteristic timing. Tendons are stiffer and more pain-sensitive after a long period without movement, which is why the pain often peaks in the second half of the night and on first getting up, then eases once you are moving. If you wake stiff elsewhere too, the surface and pillow are worth checking — see whether your pillow really affects your sleep.

Why the word “bursitis” is usually wrong

The umbrella term now used is greater trochanteric pain syndrome, and clinical reviews describe it as most commonly driven by tendinopathy or tearing of the gluteus medius and minimus tendons, with bursal inflammation frequently secondary rather than primary. Work defining the clinical syndrome established the hallmark as moderate to severe pain and tenderness over the greater trochanter, sometimes radiating down the outer thigh, with difficulty sleeping on the affected side impairing sleep quality.

The distinction is not pedantry. If the problem is inflammation in a fluid sac, anti-inflammatory treatment and rest are logical. If the problem is a tendon that has lost load capacity and is being compressed, then rest deconditions it further and the priority becomes reducing compression while progressively rebuilding capacity.

What does the treatment evidence show?

Education plus exercise outperformed injection. A prospective, single-blinded randomised clinical trial published in the BMJ compared education plus exercise, corticosteroid injection, and a wait-and-see approach for gluteal tendinopathy. Education plus exercise produced the best global outcome and pain results at the primary endpoint. Corticosteroid injection outperformed wait-and-see in the short term, but the exercise arm did better — and the gap widened at longer follow-up.

The honest counterweight is what a sham comparison found. A randomised controlled trial in postmenopausal women with greater trochanteric pain syndrome compared a targeted gluteal loading programme against sham exercises. That design is a much harder test than comparing exercise with doing nothing, and results from sham-controlled trials in this area have been more mixed than the enthusiasm for exercise programmes suggests. It is also worth saying plainly that no trial has tested sleeping position as an intervention here. The positioning advice below follows from the loading mechanism rather than from a randomised comparison, and should be held with that much confidence — it is cheap, harmless and mechanistically sensible rather than proven.

What to change tonight

• Put a pillow between your knees — a firm one, thick enough that your top thigh stays roughly level with your hip rather than dropping across your body. This is the single change most directly aimed at the mechanism.
• Consider a pillow under the waist if your mattress lets your pelvis sag, which increases side-bending stress through the hip.
• Roll slightly toward your back if direct side-lying is intolerable, supported by a pillow behind you, so you are not resting weight straight on the trochanter.
• Reconsider a very soft surface. A mattress that lets the pelvis sink increases hip adduction. This is one of the few situations where firmness has a specific rationale — the broader picture is in a mattress topper is the cheap way to test the opposite direction; the wider picture is in memory foam versus innerspring.
• Sleep on the other side in the short term, with support, while the tendon settles. Switching to your front is not usually the answer either — see is sleeping on your stomach bad.

During the day, the same logic applies: avoid sitting with legs crossed, avoid standing with your weight slung onto one hip, and be cautious with stretches that pull the thigh across the midline. Clinical guidance for insertional tendinopathies specifically advises against those stretches, because they increase compression at exactly the painful site.

When to get it assessed

Persistent lateral hip pain is worth a proper assessment rather than indefinite self-management, partly because several other things produce a similar picture: referred pain from the lower back, hip osteoarthritis (which tends to be felt deeper, in the groin or buttock, with restricted movement), and less commonly a gluteal tendon tear. See a clinician if the pain is not improving over several weeks, if it wakes you consistently, if you have weakness or a limp, or if it followed a fall or specific injury. Other night-specific pain patterns have their own differentials: burning feet at night is one worth knowing about. Night pain that is severe, progressive, or accompanied by fever, unexplained weight loss or a history of cancer needs prompt medical attention.

Frequently asked questions

Will a softer mattress help?
Often the opposite. A very soft surface lets the pelvis sink, which increases hip adduction and therefore tendon compression. A supportive surface plus a knee pillow addresses the mechanism better than softness does.

Should I stretch my hip?
Be careful. Guidance for insertional tendinopathies advises against stretches that move the hip into adduction, because they compress the tendon at the very point that hurts. Progressive strengthening is the direction the trial evidence supports.

Is it definitely not bursitis?
Bursal involvement can be present, but current clinical reviews describe it as usually secondary to gluteal tendinopathy rather than the primary problem. The practical consequence is the same either way: reduce compression, rebuild capacity.

How long does it take to settle?
Tendon problems are measured in months, not days. The randomised trial ran to follow-up well beyond the initial endpoint, and the advantage of exercise over injection grew with time. Expect a slow trajectory and judge it over weeks.

Does a corticosteroid injection help?
It beat doing nothing in the short term in the randomised trial, but education plus exercise did better overall. Injections are a reasonable conversation with a clinician, usually as a way to enable a loading programme rather than as the treatment itself.

The bottom line

Outer hip pain when you lie on your side is usually a compression story: the trochanter pressed into the mattress from below, the iliotibial band tensioned over the gluteal tendons from above, and the top knee falling across the midline making the second part worse. Calling it bursitis points you toward rest and anti-inflammatories; calling it gluteal tendinopathy points you toward reducing compression and progressively loading the tendon, which is what the randomised evidence supports. The night-time change is cheap and mechanistically sensible even though nobody has trialled it — put a firm pillow between your knees so the top thigh stays level. The daytime change is the one that actually fixes it, and it takes months.

References

1. Grimaldi A, Fearon A. Gluteal tendinopathy: integrating pathomechanics and clinical features in its management. J Orthop Sports Phys Ther. 2015;45(11):910–922. DOI: 10.2519/jospt.2015.5829.
2. Grimaldi A, Mellor R, Hodges P, Bennell K, Wajswelner H, Vicenzino B. Gluteal tendinopathy: a review of mechanisms, assessment and management. Sports Med. 2015;45(8):1107–1119. DOI: 10.1007/s40279-015-0336-5.
3. Fearon AM, Scarvell JM, Neeman T, Cook JL, Cormick W, Smith PN. Greater trochanteric pain syndrome: defining the clinical syndrome. Br J Sports Med. 2013;47(10):649–653.
4. Mellor R, Bennell K, Grimaldi A, et al. Education plus exercise versus corticosteroid injection use versus a wait and see approach on global outcome and pain from gluteal tendinopathy: prospective, single blinded, randomised clinical trial. BMJ. 2018;361:k1662. DOI: 10.1136/bmj.k1662.
5. Ganderton C, Semciw A, Cook J, Moreira E, Pizzari T. Gluteal loading versus sham exercises to improve pain and dysfunction in postmenopausal women with greater trochanteric pain syndrome: a randomized controlled trial. J Womens Health. 2018;27(6):815–829.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.