Calcium and Sleep: How It Affects Your Rest

Sleep problems are practically an American pastime. According to the National Sleep Foundation, nearly six out of ten Americans report insomnia or restless nights at least a few times a week. Instead of looking at what might be missing from their diet, many people reach straight for the pill bottle. In fact, the prevalence of sleeping pill use among university students in Malaysia is 7.5%.

Here’s the problem: most sleeping pills are not a long-term fix. They often linger in the bloodstream, leaving you with a groggy hangover effect the next day. Long-term use can impair memory, slow reaction times, and increase the risk of car and work accidents. In short, sleep drugs may knock you out, but they don’t always help your body get the deep, refreshing rest it actually needs. And honestly, if you’re still waking up exhausted after popping a pill, what’s the point, right?

Why Calcium Matters for Sleep

Calcium is usually praised for keeping bones strong, but research suggests it also plays a big role in sleep quality. One study published in the European Neurology Journal found that calcium levels in the body are higher during some of the deepest levels of sleep, including rapid eye movement (REM) sleep. Researchers discovered that when calcium levels were too low, people experienced more sleep disturbances and had trouble reaching REM sleep. When calcium levels were normalized, the participants’ sleep cycles returned to a healthier pattern.

So if you’re tossing and turning at night, maybe it’s not just stress. It could be the indication of your calcium intake. Surprising, isn’t it?

Calcium is also needed for the brain to use tryptophan, an amino acid found in many protein-rich foods. Tryptophan is the raw material the body uses to produce melatonin, the hormone that signals it’s time to sleep. This explains why dairy products, which contain both tryptophan and calcium. A glass of warm milk before bed isn’t just a cliché so it has real science behind it.

What is REM?

Rapid eye movement (REM) sleep is most commonly linked to vivid dreaming, as this stage is when dreams are typically the most intense. However, its role extends well beyond dreaming, contributing significantly to brain development and emotional regulation.

What Happens During REM Sleep?

During REM sleep, your eyes move rapidly behind your closed eyelids. That’s the only thing you can see on the outside, but inside the body, it’s a whole different story.

• Your brain activity ramps up, often leading to vivid dreams.
• Most of your muscles become temporarily paralyzed.
• Your pulse and breathing speed up and may become less consistent.

Compared to other stages of sleep, REM sleep is more like a “dream party” for your brain. That said, you’re still asleep, and most of your body loses muscle tone. Sounds weird, right? But researchers think this temporary paralysis is your body’s way of protecting you from acting out your dreams. 

The Role of Calcium, Magnesium and Other Nutrients

Calcium rarely works alone. Magnesium, zinc, and copper are also part of the sleep–wake signaling process in the brain. Nutritionists sometimes describe these minerals as “gatekeepers” that move information in and out of cells and help brain chemicals function properly.

Magnesium in particular has been studied for its role in sleep. A study trace minerals affect sleep patterns in adult women. The study found that low magnesium intake was linked to chronic insomnia and restless, broken sleep with frequent nighttime awakenings. On the other hand, women who had a higher intake of magnesium (and less aluminum) enjoyed more restorative sleep.

Common Causes of Low Calcium

Several factors can contribute to low calcium levels, which may in turn affect sleep. These include:

• Diets low in calcium-rich foods such as dairy, leafy greens, or fortified foods
• Vitamin D deficiency, which makes it harder for the body to absorb calcium
• Stress, which can deplete both calcium and magnesium reserves
• Poor balance of calcium and magnesium in the diet

Calcium and Sleep: How to Get Enough

Most adults need around 1,000 mg of calcium per day. Women over 50 and men over 70 need slightly more, about 1,200 mg daily. Meeting these needs through food may help improve sleep quality naturally.

Good sources of calcium include:

• Dairy products: milk, cheese, yogurt
• Leafy greens: kale, collard greens, bok choy
• Fortified foods: plant-based milks, cereals, orange juice
• Fish with edible bones: sardines, canned salmon
• Nuts and seeds: almonds, chia seeds, sesame seeds

Other Ways to Improve Sleep

Even with enough calcium, sleep problems can still persist if daily habits are out of balance. Steps that may help include:

• Sticking to a regular bedtime and wake-up time
• Limiting caffeine and alcohol, especially in the evening
• Reducing screen time before bed to support natural melatonin release
• Practicing stress management with techniques such as yoga or meditation

Supplements may be an option if diet alone doesn’t meet your calcium needs, but it’s always best to speak with a healthcare professional before starting.

The Bottom Line

When it comes to sleep, calcium may not get as much attention as melatonin or sleeping pills, but it deserves a spot in the conversation. Research shows that calcium and sleep are closely linked: low calcium levels can disturb REM sleep, while adequate intake supports deeper, more restful nights.

Calcium helps the brain turn tryptophan into melatonin, making foods like dairy a natural sleep aid. Combined with magnesium, it supports the signaling systems that regulate the sleep–wake cycle.