Why Your Back Is Stiff in the Morning (and When It Is Normal)

Your back is stiff in the morning because your spinal discs spent the night out drinking. While you slept, each disc absorbed fluid from surrounding tissues and swelled by 10-20% in height. That swelling makes the disc taller and the spine temporarily stiffer, which is why bending forward right after waking up can feel so stiff. After 20-30 minutes, the light compressive forces of movement and being upright expel some of the water out of our discs, reducing stiffness. A 2023 systematic review study found evidence linking morning spinal stiffness to real disc changes [1]. These changes don’t mean that our discs are broken, but there are some things to look out for.

What is actually happening overnight

Your discs are like jelly filled onions where the jelly centre, called the nucleus pulposus, is mostly water and other structural proteins. When you stand and walk during the day, gravity and muscle forces squeeze water from the jelly and out of the discs. By bedtime, you’re 1-2 centimetres shorter than you were in the morning. If someone ever questions your height you can tell them that they should’ve seen you in the morning! When you lie down, compressive forces drop to nearly zero, and the disc pulls that fluid back into the jelly by osmosis. This process was first described in a foundational review of disc biology, where this cycle was framed as a normal feature of how a healthy disc moves nutrients in and waste out [2].

By morning, our discs are at their tallest and most hydrated state of the day. Tall and hydrated also means stiffer. The layers of the onion are under greater internal pressure from the jelly, and the spine has less room to bend without resistance. That is the sensation you feel when you swing your legs out of bed and reach to put on your socks.

When morning stiffness is normal

The 20-30 minute rule: If the stiffness eases within half an hour of getting moving, you are experiencing healthy disc biology. A few markers of normal morning stiffness:

• Duration under 30 minutes. It loosens with light movement.
• No night pain. Your back pain does not keep you up at night (occasional pain from tweaking your back is normal).
• Same on most days. Variable with how you slept or with changes in physical activity on the previous day, but not progressively worse week over week.

If that matches you, your morning stiffness is the price your spine pays for being a load-bearing structure that also needs to swap fluid every night. I guess that’s a fair trade.

When morning stiffness is a red flag

There are a couple of things to watch for:

• stiffness that does not improve for 60 minutes after waking
• pain that improves with activity but not with rest
• pain that regularly wakes you in the second half of the night
• age of onset of the above factors
  • Johns Hopkins Arthritis Center mentions that 80% of people with axial arthritis (in this case ankylosing spondylitis of the spine) experience onset before age 30, and only 5% with arthritis experience onset of symptoms after age 45 [3].

If you feel that the above symptoms describe you, then it may be time to talk to your doctor about seeing a rheumatologist. And the standard red flags apply at any hour: loss of bowel or bladder control, numbness in the saddle area (parts of your body that would contact a saddle if you were sitting on a horse), rapidly worsening leg weakness, back pain with fever, or unexplained weight loss. Those need same-day medical assessment.

What to do in the first 20 minutes after waking

The goal is to remain in a neutral spine posture and let gravity and movement do their thing. Simple. General things to remember:

1. Avoid rounding your spine into extreme flexion (rounding forward) and extension (leaning backwards)
   1. The extra fluid means extra forces on our tissues with bending
   2. Bring your feet closer on a raised object to put on socks and shoes. Hinge at your hips when you have to bend over to pick things up. See my previous newsletter on movement tips here.
2. Stand up. Walk around a bit. Make a coffee. Open the blinds. Go say hi to the dog. Putter around the kitchen.

Bonus points if you can get out for a walk soon after waking. But in general, get moving and avoid extreme postures. Gravity and compressive forces usually take care of the rest.

Other quick tips to try

I found a few tips that others have tried.

• Sleep position. If you sleep on your side, put a pillow between your knees. If you sleep on your back, put a small pillow under your knees. Both keep the lumbar spine in a more neutral position overnight.
• Pillow height. Your head pillow should fill the gap between your shoulder and your ear, no higher. Same as the tip above, our goal is to keep the spine in a neutral position.
• Evening hydration. Drink most of your daily water before 7pm. I’m not so sure about this one but you can give it a try. I don’t think there’s any particular magic about restricting hydration timing but I could see how this is related to sleeping longer throughout the night if you frequently wake up to go to the bathroom.
• A 5-minute pre-bed walk. This is biomechanically sound, in theory. A little bit of extra gentle compression before bed could squeeze out additional fluid prior to sleeping, giving you potential excess “room” for your discs to swell overnight and hopefully reduce stiffness when you wake up in the morning.

Four weeks is the floor for noticing a real change in tissue behaviour. If your morning stiffness duration drops from 25 minutes to 10 minutes over that window, you have your answer about which lever worked.

As always, have a great weekend. Best, Mitch

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References

[1] Chamoro et al., 2023 — 10.1016/j.joca.2023.04.014. Association between clinical findings and the presence of lumbar spine osteoarthritis imaging features: a systematic review. Osteoarthritis and Cartilage, 31(9), 1158-1175.

[2] Adams & Roughley, 2006 — 10.1097/01.brs.0000231761.73859.2c. What is intervertebral disc degeneration, and what causes it? Spine, 31(18), 2151-2161.

[3] Johns Hopkins Arthritis Center — Ankylosing Spondylitis.

Disclaimer: this content is educational only and does not constitute medical advice. See a practitioner if you suspect serious spinal trauma from a fall or accident, or if you experience any of the following red flag symptoms: loss of bowel or bladder control, numbness in the groin or saddle area, rapidly worsening leg weakness, back pain with fever or feeling generally unwell, or unexplained weight loss with back pain.