Back Spasm at Night: What to Do When It Locks Up in Bed

You turn over at two in the morning and your back locks. The muscle clamps, you can’t find a position that doesn’t hurt, and getting out of bed takes several minutes of negotiation.

This is muscle spasm, and heat is the right tool for it. There’s usually no swelling to worry about, and the pain is coming from muscle guarding rather than fresh tissue damage. See heat or ice: a physio’s decision guide.

What to do at 2am

1. Stop trying to stretch out of it. A muscle in spasm resists being pulled and tightens harder.
2. Find the position that hurts least and stay there for a few minutes. For most people that’s on the side with knees bent and a pillow between them, or on the back with a pillow under the knees.
3. Breathe out slowly, several times. Sounds soft, works. Breath-holding and bracing feed the spasm.
4. Heat on, 15 to 20 minutes. Sit or lie with the pad over the area, lowest setting, cover on. Set a timer. Placement: heating pad for lower back pain.
5. Then move a little. Small knee rocks side to side, or a slow walk to the kitchen and back.

A warm shower does the same job if you can stand up for it. Run the water on your lower back for a few minutes. See moist heat vs dry heat.

Set the timer before you lie down

This is the situation where people fall asleep on a heat pad. You’re exhausted, it’s the middle of the night, the warmth is the first relief you’ve had in an hour.

A pad against your skin for six hours is how low-temperature burns happen, and painkillers make you less likely to notice. Set a phone alarm, or plug the pad into a timer switch. Never lie on top of it. See is it safe to sleep with a heating pad on? and, for who’s most at risk, who should not use a heating pad.

Getting back to sleep

• Side-lying, knees bent, pillow between the knees to stop the top leg dragging your pelvis round.
• On your back, pillow under the knees to take the pull off the lower back.
• Not on your front, which extends the lower back and often provokes it further.
• Getting up: roll onto your side first, drop your legs off the edge, push up with your arms. Don’t sit straight up from flat.

Using warmth earlier in the evening, before you get into bed, often means a better night in the first place: warmth before bed. Cramp that seizes the calf rather than the back is a different thing: calf cramps at night.

The next few days

Most episodes settle within days to a couple of weeks. What helps is staying gently active, not bed rest. Heat before movement, short walks often, and back to normal activity as the pain allows. On getting that order right, see “my physio said use heat” — but how, exactly?

A pharmacist can advise on an over-the-counter painkiller for the first few days. Full detail: back pain: the first two weeks, and on the limits of a pad, when a heating pad helps back pain, and when it won’t.

Why it happens at night

Usually the back was already irritated during the day, from lifting, a long drive or hours at a desk, and hours of stillness let the muscles tighten around it. The turn in bed is the trigger, not the cause. A weekend of gardening or housework is a common setup.

If it keeps happening, the thing to look at is the daytime load, not the mattress.

Get help urgently if…

• You have numbness around your groin or buttocks, or trouble passing or controlling urine. Go to A&E now.
• You have weakness in a leg, or it keeps giving way. Pain running down the leg: sciatica and heat.
• The pain is just as severe lying completely still, or wakes you every night
• You have a fever, unexplained weight loss, or a history of cancer
• It followed a fall, especially if you’re older or have osteoporosis. See osteoporosis and spinal compression fractures and back pain in older people.

Pain that’s genuinely worse at rest than on movement is the one that deserves a doctor rather than a heat pad.

Clinically reviewed by: Nigel Chua (Hand Occupational Therapist) & Louise Yow (Physiotherapist). This article is general information, not a diagnosis. electricheatpad.com sells electric heat pads.