I have been presented with the following conundrum. Either you sleep on your back and snore, or sleep on your right side and get acid reflux, or sleep on your left side and put a heavier load on your heart, thus weakening it.

I d not have or seek scientific evidence for the first two claims. I have (weak) empirical evidence to accept them as plausible (I do snore more on my back for instance). What I am asking here is about the third claim.

Does sleeping on your left side put such an extra burden of weight on your heart that it might be unhealthy?

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    Exercise puts a greater burden on your heart, but I wouldn't say it is bad for the heart. The heart adapts in a positive way. Maybe sleeping on your left will strengthen your heart long term and be beneficial. – Kenshin Sep 30 '13 at 4:19
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    I've always heared that sleeping on your left side aswell due to your heart, but i've always figured it was a myth since your heart is mostly in the center anway, and just slightly bigger to the left side. – Lyrion Sep 30 '13 at 13:36
  • @Lyrion: That is what I was thinking too. It should make no dfference; but then... – yrodro Sep 30 '13 at 15:34
  • @Compro01: Although your comments do not exactly answer my question, they seem to cover close the "heart" of the matter. Care to upgrade to an answer? If there isn't a more exacting one, I should accept yours. – yrodro Sep 30 '13 at 18:22
  • With or without the elbow under the ribs? How hard is the mattress? – Cees Timmerman Jan 25 '14 at 16:43


According to this study, patients with congestive heart failure tend to unconsciously avoid sleeping on their left side, whereas healthy patients don't display this avoidance. The reason for this avoidance is unknown, though the paper offers several lines of speculation, ranging from discomfort to various forms of cardiac impairment. As far as I can find, no one has yet followed up on these and even if the reason is the impairment, whether this extends to healthy people is an open question.

Though not directly related to the heart, sleep apnea is frequently (about half of cases) position dependant (i.e. Apneas only occur when in a certain sleep position). In persons with sleep apnea dependant on the left side, sleeping on the left side would have definite deleterious effects, including cardiac ones. This study investigated the frequency of associated positions with sleep apnea, though the actual numbers are behind the paywall and out of my sight.

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    Here is a paywall free version of the study. – Mark Mendoza Oct 14 '13 at 3:59
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    This is going to be very personal but whenever I sleep on my left side; I feel sick, my shoulder and my chest gets stretched and I can feel my heart bumping very hard which also effects my breathing heavily and I turn right side when I am aware of this situation to relax. So I think this needs to be examined very widely. Hope it has no serious effects. Just people feeling uncomfortable about it. – Berker Yüceer Oct 14 '13 at 11:04
  • @MrKomandez - Seems the study didn't contain all the data I thought it did from the abstract. It only compared supine vs. non-supine, lumping all other positions into one. – Compro01 Oct 14 '13 at 21:27

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