Which pillow to choose if you sleep on your side (and why your neck hurts in the morning)

Most people in Spain and Portugal sleep on their side. It is the most common position and the most demanding on a pillow: it has to fill the whole gap between ear and shoulder. If it does not, the neck spends the night bent.

The 10-second test

Lie on your side on your bed with your usual pillow and ask someone to look at your neck from behind. If the line of the spine rises or drops at the head, the pillow is the wrong height. If it is straight, it is right.

The four factors

1. Height

On your side the ideal height is the distance from your ear to the edge of your shoulder, usually 10–14 cm. Broad shoulders need more; soft mattresses a little less, because the shoulder sinks in.

2. Firmness

Side sleepers need medium-high firmness: a soft pillow flattens and loses height halfway through the night. That is why so many people end up folding the pillow in two.

3. Material

• Fibre: cheap, flattens fast.
• Feathers: comfortable at first, no support.
• Memory foam: moulds with body heat and springs back every morning. It keeps the height all night.

4. Shape

A rectangular pillow spreads support evenly. A contour cervical pillow has a higher zone for the neck and a lower one for the head, so the neck is held and aligned.

Our recommendation

For side sleeping: a memory-foam cervical pillow, high side under the neck, breathable cover. It is the combination that meets all four factors without measuring anything.

Getting used to a new pillow

Give it 3–5 nights. You will notice the new height at first; that is normal. Do not stack a second pillow on top and do not fold it.

Signs your current pillow is the problem

• You wake up with a stiff neck that eases by mid-morning.
• You change position many times a night.
• You fold the pillow or put a hand under it to gain height.

If two of the three sound familiar, changing the pillow is the cheapest fix you will ever try.