Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I remember hearing various sleep related advice as a child, like "sleep on your right side", or " have your head pointed in X direction".

Is there any biological reason why sleeping on one side versus another, or with a head pointed in some direction is beneficial for humans?

share|improve this question

The enWikipedia article summarizes the best/only real research on positions that I am aware of. I read a book in high school (that is to say it was old and I have no idea what the title was) that claimed that the semi-fetal position was the best, as it supposedly maximized protection without compromising breathing too much. I can't say I've seen anything that would indicate your head's direction actually matters, except as it depends on the position of the rest of your body. Do you mean facing North or the door? That's some Feng Shui stuff or something similar, which is meaningless.

In terms of which side to sleep on, there is actually an answer! Well, maybe. Sleeping on your left side aggravates heartburn more than sleeping on the right side1, but sleeping on your left may be somewhat associated with heart problems.2 From what I can read from the studies, the heartburn one sounds more causative, but then again dying is worse than a little heartburn... In the end, though, about the only thing that matters is that sleeping on yours side can lower the amount of snoring (annoying) and sleep apnea (unhealthy).

share|improve this answer
By head direction I meant compass orientation like north or east – Alex Stone Aug 7 '13 at 12:46

Disclaimer: Not in any way my area of expertise. Maybe someone else can expand

In relation to pregnancy, there exist one australian study (Stacey et al. 2011) that reports an increased risk of still-birth for women that sleep on their back at the later stages of pregnancy. The purported mechanism is pressure from the uterus on the inferior vena cava and aorta, restricting blood flow. Lowest risk was found for women that sleep on their left side (less pressure on the liver). Another recent study from Ghana (Owusu et al. 2013) has found similar results, with associations between sleep position (supine position) and birth weight or risk of still birth. However, the studies are relatively small and the results must be further corroborated.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.