Left side vs right side: does it matter

For most people it makes little difference whether they sleep on the left or right side, and switching during the night is normal. It matters in a few cases. The Sleep Foundation notes that left-side sleeping may help people with acid reflux, while some people with heart conditions may prefer the right side¹.

The short answer for most people

If you are healthy and have no reflux or pain, choose whichever side is comfortable. Most people move between sides several times a night without waking. Switching spreads pressure between both hips and both shoulders, so it can be a good thing.

What matters more than the side is the setup: head pillow height, knee support and arm support. Those are covered in the complete guide to sleeping on your side.

Case 1: acid reflux and heartburn

The Sleep Foundation notes that left-side sleeping may benefit people who experience acid reflux¹. A common explanation is the shape and position of the stomach, which sits mostly to the left. On the left side, the junction between the stomach and the food pipe sits higher than the stomach contents.

Position is only one part of managing reflux. The NHS suggests these changes²:

• Raise the head of your bed by around 10 to 20 cm, using wood, bricks or books under the legs, so your chest and head are above your waist.
• Do not try to get the same effect by stacking extra pillows under your head, which can bend you at the waist.
• Do not eat within 3 or 4 hours of going to bed.
• Avoid clothes that are tight around the waist, and food or drink that triggers your symptoms.

If reflux keeps you awake regularly, speak to a GP or pharmacist about it.

Case 2: heart conditions

The Sleep Foundation notes that right-side sleeping may be preferred by people with some heart conditions¹. This is an area for your cardiologist or GP, not a guide. If you have a heart condition and notice that one side feels uncomfortable or makes you breathless, mention it at your next appointment.

Case 3: pain on one side

Pain usually decides it. If one hip or shoulder is sore, sleep on the other side, with support so the sore side is held level rather than hanging. The NHS suggests seeing a GP if shoulder pain has not started to feel better after 2 weeks⁴.

• Sore top hip: a pillow between the knees keeps the leg level. See how to sleep on your side without hip pain.
• Sore top shoulder: rest the arm on a pillow at chest height. See why your shoulder hurts when you sleep on your side.
• Sore lower back: knees slightly bent with a pillow between them. See side sleeping and lower back pain.

Left vs right at a glance

How to stay on the side you choose

Choosing a side is easy. Staying on it for 7 hours is harder, because the body moves freely in sleep. A few things help:

1. Put a pillow behind your back to block the roll onto your back. 2. Hug a pillow in front of you to block the roll onto your stomach. 3. Put the bed against the wall on the side you want to avoid facing, if that suits your room. 4. Make the side you want more comfortable than the alternative, with the right head pillow height.

A crescent body pillow handles points 1 and 2 at once, because the curve sits in front of you and the tips can tuck behind. The Cove Classic is 52 inches tip to tip and works on either side. Flip it over when you switch.

Switching sides on purpose

If one side is sore, deliberate switching can help. Start the night on the side that hurts least, and if you wake up, turn to the other side rather than lying awake on the sore one. Keep a pillow between your knees on both sides so the top leg stays level whichever way you face. Over a week, note which side you wake on and how each hip and shoulder feels, so you can see whether the switching is helping. Small, steady changes usually beat one big change.

Sharing a bed

If you share a bed, the side you sleep on also decides whether you face your partner or face away from them. Many couples end up back to back, which suits a body pillow in front of each person. If you are on the left side of the bed and want to sleep on your left side, you will face the edge of the bed, so check there is room for a pillow on that side.

Does it change how well you sleep

There is no strong evidence that one side gives better sleep quality for healthy adults. The Sleep Foundation's general advice is to choose a position that keeps your spine in a neutral line and lets you sleep without pain³. If you sleep well on your right side, there is no need to change.

Keep reading

• Should you sleep with a pillow between your knees
• What size body pillow do I need