After a big dinner, the couch calls. On a long day, so does the bed. What you do in the hours between your last bite and falling asleep may make a real difference to how your evening, and your night, feel.
Researchers have measured what happens to gas and stomach acid in several of these positions. Here's how the common options compare.
Option 1: Staying upright
What the research shows. In a Barcelona study, eight healthy volunteers had gas infused into the small intestine on two separate days, once upright and once lying on their backs. Upright, only about 13 mL of gas was retained after an hour, compared with 146 mL lying down. Gas also cleared faster: 72% versus 49% of a gas marker had cleared at 60 minutes (Dainese et al., 2003).
Best for: the first couple of hours after dinner, especially if bloating is your main issue. Sitting up rather than lying back, tidying the kitchen or taking a gentle stroll all keep you upright.
Trade-off: hardly any, other than the pull of the couch.
Option 2: Lying down soon after eating
What the research shows. In the same study, lying on your back slowed the movement of gas. For heartburn, the timing of bed matters too. In a Japanese study that compared 147 people with reflux disease with 294 matched people without it, going to bed less than 3 hours after dinner was linked to about 7.5 times the odds of reflux disease, compared with waiting 4 hours or more (Fujiwara et al., 2005). That kind of study can't prove cause and effect, but it fits with the next one.
A US crossover trial tested timing directly in 30 people with reflux symptoms. When they ate a standard meal 2 hours before bed, they had significantly more acid reflux while lying down than when they ate the same meal 6 hours before bed. Interestingly, their overall symptom scores didn't differ between the two nights (Piesman et al., 2007).
Best for: times you truly need to rest. If so, a propped-up, reclined position keeps you closer to upright than lying flat.
Trade-off: more nighttime reflux in people prone to it, and slower gas movement.
Option 3: Sleeping on your right side
What the research shows. In a Dutch study, 57 people having ambulatory reflux monitoring also wore a sensor that recorded their sleep position. Acid exposure in the esophagus was higher when they lay on their right side, a median of 1.2% of the time, compared with 0.0% on the left side. Acid also took longer to clear on the right side, a median of 90 seconds versus 35 seconds on the left (Schuitenmaker et al., 2022a).
Best for: people without heartburn who find it comfortable.
Trade-off: if you're prone to nighttime reflux, it came out as the least favorable position in this study.
Option 4: Sleeping on your back
What the research shows. In the same Dutch study, back sleeping fell in between, with a median acid exposure of 0.6% of the time and a median acid clearance time of 76 seconds (Schuitenmaker et al., 2022a). And as the gas study showed, lying flat on your back slows the movement of gas compared with being upright.
Best for: people who sleep well on their backs and don't have reflux or much evening bloating.
Trade-off: a middle-ground option for reflux, and not ideal for gas.
Option 5: Sleeping on your left side
What the research shows. The left side came out best in the Dutch monitoring study, with the least acid exposure and the fastest acid clearance. The same team then ran a randomized trial with 100 people with nighttime reflux symptoms, all advised to sleep on their left side. Half got a wearable device that vibrated whenever they rolled onto their right side, and half got a sham version. In the device group, 44% cut their nighttime reflux score by at least half, compared with 24% in the sham group, and the device group had more reflux-free nights (Schuitenmaker et al., 2022b).
Best for: anyone with nighttime heartburn or regurgitation.
Trade-off: staying there can take practice. A pillow tucked behind your back can make it easier to stay on your side.
Side by side, and what to do with it
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Upright: gas moved through fastest; a good default for the first couple of hours after dinner.
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Lying down within 2 to 3 hours of dinner: linked with more reflux, and slower gas movement.
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Right side: the most acid exposure of the sleep positions measured.
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Back: in between for reflux.
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Left side: the least acid exposure and the fastest clearance.
When your schedule allows, try to finish dinner about 3 hours before bed. Stay upright for the first part of the evening, and fit in a short, easy walk if you can. If you get nighttime heartburn, fall asleep on your left side.
A caveat: most of this research involved people with reflux, and the gas study involved eight healthy volunteers. If you sleep well and wake up comfortable, there's no need to overhaul your evenings.
When to see a doctor
Frequent heartburn, or heartburn that keeps coming back despite these changes, is worth discussing with your doctor. Get checked promptly for trouble or pain when swallowing, persistent vomiting, unexplained weight loss or black stools. Chest pain always needs urgent evaluation, because heart problems can feel like heartburn.
Sources
- Dainese R, Serra J, Azpiroz F, Malagelada JR. Influence of body posture on intestinal transit of gas. Gut. 2003;52(7):971-4. PMID 12801953
- Fujiwara Y, Machida A, Watanabe Y, et al. Association between dinner-to-bed time and gastro-esophageal reflux disease. Am J Gastroenterol. 2005;100(12):2633-6. PMID 16393212
- Piesman M, Hwang I, Maydonovitch C, Wong RK. Nocturnal reflux episodes following the administration of a standardized meal. Does timing matter? Am J Gastroenterol. 2007;102(10):2128-34. PMID 17573791
- Schuitenmaker JM, van Dijk M, Oude Nijhuis RAB, Smout AJPM, Bredenoord AJ. Associations between sleep position and nocturnal gastroesophageal reflux: a study using concurrent monitoring of sleep position and esophageal pH and impedance. Am J Gastroenterol. 2022;117(2):346-351. PMID 34928874
- Schuitenmaker JM, Kuipers T, Oude Nijhuis RAB, et al. Sleep positional therapy for nocturnal gastroesophageal reflux: a double-blind, randomized, sham-controlled trial. Clin Gastroenterol Hepatol. 2022;20(12):2753-2762.e2. PMID 35301135
This article is for general information and isn't medical advice. Talk to your healthcare provider about frequent heartburn, and seek urgent care for chest pain.
