Sleeping on your belly may not be the best thing for your spine. But, if you’re used to sleeping like this, there are steps you can take in order to protect your back.

Many people around the world simply enjoy sleeping in their stomachs; others do it to reduce snoring or the risk of sleep apnea. However, this might not be the best idea. Sleeping in this position is taxing on our backs, which can lead to poor sleep quality at night and physical discomfort during the day. Pregnant women, in particular, should try to avoid this sleeping position if possible.

Spine trouble

Sleeping on the stomach isn’t, statistically speaking, very common; according to the Sleep Foundation, people spend less than 10% of their sleep time sleeping in this position. This comes down to some very practical reasons: this position can create strain in your back and neck, causing acute and in some cases chronic pain.

Sleeping on our stomachs places undue strain on our spines, especially on our neck and back, which prevents them from assuming a neutral position. However, sleeping without a pillow, or with a flat, stomach sleeper pillow, can help reduce the strain and promote spine health and sleep quality if you’re used to sleeping on your stomach. Placing a flat pillow under the stomach and pelvis area can help to keep the spine in better alignment.

According to the University of Rochester’s Medical Center, sleeping on our stomach places stress on the back and spine because, in this position, most of our weight is supported by the middle part of our bodies. In this position, our torsos tend to ‘sink’ lower into the mattress than they would normally, and our bodies’ weight comes rests on our midsection. This results in our backs arching, which stretches our spines out of their normal shape.

The mechanical stress produced by this change leads many to experience some type of pain upon waking. Some of this is caused directly by tissue fatigue and wear, while another portion is caused by damage incurred by the nerve bundles inside the spine. Both make can make it hard for people to fall asleep, make it more likely that they will wake up during the night, and impact overall lower sleep quality.

Another issue with this sleeping position is that it forces people to turn their heads to the side while sleeping. This puts the head and spine out of alignment (it twists the neck), which contributes to the emergence of headaches, neck, and shoulder pain. Over time, it can also lead to more serious complications such as a hernia — the rupture of a gelatinous disk between the vertebrae in our spines — which can be extremely painful and debilitating.

Pillows help keep our spines aligned when we sleep — so can they help with sleeping on our stomachs? To an extent. Flat pillows under our pelvis and midsection help maintain the shape of our spines during sleep, taking some of the mechanical load off of the disks between vertebrae.

Sleeping without a pillow helps reduce the angle our necks take when we sleep on our stomachs, which similarly helps by reducing the strains these disks experience during the night.

Pregnant women that like to sleep on their stomachs can generally maintain this position during the first trimester without discomfort. As the pregnancy progresses and their stomach grows, however, it becomes uncomfortable — enough so that it can start seriously interfering with sleeping quality. It’s therefore generally advised that pregnant women do not sleep on their stomachs if they can, as long-term disruption in sleeping (sleep deprivation) can contribute to a whole host of issues such as premature birth, longer and more painful labor, and postpartum depression.

Sleeping on the left side is the main recommended position for pregnant women. This helps prevent the pain associated with sleeping on their stomachs while also keeping pressure off their liver and the inferior vena cava — the vein that cycles blood from the legs back to the heart. Furthermore, it helps improve blood flow to the kidneys, uterus, and fetus.

While things are pretty clear-cut for pregnant women, for the rest of us, it remains somewhat murkier. Research on exactly how different types of pillows interact with various sleeping positions, and their effect on our spines, is still relatively sparse. The best approach is to listen to your body: if your experience pain after sleeping, that’s a reliable indicator that something in your sleeping habits isn’t working for your body.