Other than a “space headache,” what might be the downsides of sleeping at a slight head-down tilt to accelerate fat loss?
The Risks and Benefits of Mild Trendelenburg Position to Reduce Body Fat
5/5 - (26 votes)
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In my last video, I noted how lying at a slight, six-degree head-down tilt for a few hours can boost fat burning. Now obviously, you wouldn’t want to lie tilted back if you had a heart condition, such as congestive heart failure. As many as eight to 12 cups (1.90 to 2.90 L) of blood may be displaced into the torso from the extremities at a tilt like that, so you have to have the cardiovascular fitness to handle it. Acid reflux could also be a problem. In fact, we typically tell heartburn patients to do the reverse—put a few bricks under the posts at the head of their bed to have gravity work in their favor to keep stomach acid down where it belongs. But for those without medical problems, is there a harm in lying tilted back for a few hours? Well, it could give you a “space headache.”
In movies, astronauts are shown practicing underwater. But the gold standard for simulating the physiological effects of the weightlessness of outer space is HDBR, head-down bed rest. On Earth, our blood tends to collect in our legs, so our body is designed to force blood headward. In outer space, our body is still trying to push our blood “up,” so without Earth’s gravity, blood pushes upwards to our head and chest––just like it does when we lie tilted back. This realization came from cosmonauts returning from the space station feeling as though they were slipping towards the foot of the bed, and only feeling “normal” when they were tilted six degrees back.
All of the extra blood pooling in the head is thought to contribute to the headaches reported by up to 70 percent of astronauts during space flights. And a similar percentage of individuals suffer headaches from prolonged head-down bed rest. That’s after days, though. In preparation for a mission to Mars, space agencies put people through head-down bed rest for prolonged periods—eating, bathing, and toileting all while lying in bed tilted back for literally months at a time.
Extended stretches of head-down positioning for weeks may impair lung function, brain function, and immune function, and cause a loss of muscle mass. On the last Apollo mission, the astronauts lost about five pounds (2.30 kg) of fat over the 12-day trip. But they also lost about two pounds (0.90 kg) of lean body mass. Prolonged weightlessness or bedrest, regardless of tilt, can result in muscle and bone loss. But just sleeping on a slant by putting a few bricks under the posts at the foot of your bed could potentially give you a boost in fat metabolism without the long-term adverse effects.
If you want to try it, a note of caution: take it slow when standing back up. After just four hours of a six-degree head-down tilt, most people experience reduced “orthostatic tolerance.” When anyone stands suddenly after sitting or lying for a while, you can get a “head rush,” feel dizzy, faint, or lightheaded as the blood drains from your brain down into your legs before your body can compensate. This can be exacerbated by lying with your head tilted back, so be careful and get up gradually. Drinking two cups (0.50 L) of cold water 30 minutes before rising may also help.
Do not try this at home if you have any heart or lung issues, or problems with your brain (like head trauma) or eyes (even a family history of glaucoma disqualifies you). Ask your physician if they think it’s safe for you to sleep in “mild Trendelenburg.” Friedrich Trendelenburg was a pioneering surgeon who popularized the use of what was formerly referred to as “head-down position” for certain abdominal and pelvic procedures. Angling the operating table back 15 to 30 degrees pulls some abdominal organs out of the way to help declutter the surgical field, resulting in what is now widely known as the Trendelenburg position.
Steep Trendelenburg (at a 25- or 30-degree tilt) has been associated with transient visual problems, thought due to the increase in pressure within the eyeball. Cautions have been issued for those at risk for glaucoma (a disease of increased eye pressure) to avoid “inversion” therapy, where people hang upside down, as well as yoga positions like handstands, which can have a similar effect.
Lying back in mild Trendelenburg, like around six degrees, can cause a fleeting bump in eye pressure that appears to normalize within a few hours. But the pooling of blood in the head may reduce blood flow to the retina sufficient to impair nerve impulses. Similar effects have been noted within the brain. Intracranial pressure also normalizes after a few hours at a six-degree head-down tilt, but the overall blood flow through the brain does drop a bit. This is why you shouldn’t try this if you have eye or brain pathology.
To my surprise, sleeping in mild Trendelenburg was actually put to the test to prevent bone loss in sedentary individuals. Restrict people’s activity to walking less than two miles (3.20 km) a day on average, and within a year they can lose as much as 15 percent of their bone mineral density. What happened to those randomized to the same exercise restriction, but also combined with sleeping at a two-degree head-down tilt that was increased by two degrees about every two months, so they ended up sleeping at a 14-degree slant (or whatever angle they felt comfortable with) by the end of the year? Not only did it completely block the bone loss, they built more bone. Despite the movement restriction, they ended up with about 12 percent greater bone mineral density than when they started. Note that this bone-building effect was only apparent in sedentary individuals. Another group randomized to the same mild Trendelenburg, but assigned to run an average of five or six miles (8 or 9.5 km) a day just maintained their same skeletal integrity.
The study was repeated, and the same remarkable effects were found. There is something about the “periodic fluid redistribution” that comes with sleeping tilted back at night that actively builds both bone density and volume after the day-long stagnant pooling of blood in the legs of sedentary individuals. The research team claims this is just the beginning to the benefits, citing “unpublished studies” asserting a near panacea of perks to sleeping in Trendelenburg. I can’t be too critical of this apparent dodge when I can’t point to a single study supporting my supposition that it will help with weight loss. As far as I can tell, it’s never been tried or even proposed. What I can promise is that any researchers who take on the mantle of putting it to the test will definitely have their study featured in a video on NutritionFacts.org.
Please consider volunteering to help out on the site.
- Moro C, Pillard F, de Glisezinski I, et al. Atrial natriuretic peptide contribution to lipid mobilization and utilization during head-down bed rest in humans. Am J Physiol Regul Integr Comp Physiol. 2007;293(2):R612-617.
- Lathers CM, Diamandis PH, Riddle JM, et al. Acute and intermediate cardiovascular responses to zero gravity and to fractional gravity levels induced by head-down or head-up tilt. J Clin Pharmacol. 1990;30(6):494-523.
- Albarqouni L, Moynihan R, Clark J, Scott AM, Duggan A, Del Mar C. Head of bed elevation to relieve gastroesophageal reflux symptoms: a systematic review. BMC Fam Pract. 2021;22(1):24.
- van Oosterhout WPJ, Terwindt GM, Vein AA, Ferrari MD. Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity. Cephalalgia. 2015;35(4):335-343.
- Bareille MP, Maillet A. Human: bed rest/head-down-tilt/hypokinesia. In: Generation and Applications of Extra-Terrestrial Environments on Earth. 1st ed. River Publishers; 2022:133-145.
- "Montmerle S, Spaak J, Linnarsson D. Lung function during and after prolonged head-down bed rest. J Appl Physiol. 2002;92(1):75-83. "
- "Liu Q, Zhou R, Chen S, Tan C. Effects of head-down bed rest on the executive functions and emotional response. PLoS One. 2012;7(12):e52160. "
- Kelsen J, Bartels LE, Dige A, et al. 21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog. Cytokine. 2012;59(2):403-409.
- Ritz P, Acheson KJ, Gachon P, et al. Energy and substrate metabolism during a 42-day bed-rest in a head-down tilt position in humans. Eur J Appl Physiol Occup Physiol. 1998;78(4):308-314.
- Johnson PC, Leach CS, Rambaut PC. Estimates of fluid and energy balances of Apollo 17. Aerosp Med. 1973;44(11):1227-1230.
- Krebs JM, Schneider VS, Evans H, Kuo MC, LeBlanc AD. Energy absorption, lean body mass, and total body fat changes during 5 weeks of continuous bed rest. Aviat Space Environ Med. 1990;61(4):314-318.
- Butler GC, Xing HC, Northey DR, Hughson RL. Reduced orthostatic tolerance following 4 h head-down tilt. Eur J Appl Physiol Occup Physiol. 1991;62(1):26-30.
- Figueroa JJ, Basford JR, Low PA. Preventing and treating orthostatic hypotension: as easy as A, B, C. Cleve Clin J Med. 2010;77(5):298-306.
- Martin JT. The Trendelenburg position: a review of current slants about head down tilt. AANA J. 1995;63(1):29-36.
- Halm MA. Trendelenburg position: “put to bed” or angled toward use in your unit? Am J Crit Care. 2012;21(6):449-452.
- Taketani Y, Mayama C, Suzuki N, et al. Transient but significant visual field defects after robot-assisted laparoscopic radical prostatectomy in deep trendelenburg position. PLoS One. 2015;10(4):e0123361.
- Friberg TR, Sanborn G. Optic nerve dysfunction during gravity inversion. Pattern reversal visual evoked potentials. Arch Ophthalmol. 1985;103(11):1687-1689.
- Cramer H, Krucoff C, Dobos G. Adverse events associated with yoga: a systematic review of published case reports and case series. PLoS One. 2013;8(10):e75515.
- Linder BJ, Trick GL, Wolf ML. Altering body position affects intraocular pressure and visual function. Invest Ophthalmol Vis Sci. 1988;29(10):1492-1497.
- Marshall-Goebel K, Mulder E, Bershad E, et al. Intracranial and intraocular pressure during various degrees of head-down tilt. Aerosp Med Hum Perform. 2017;88(1):10-16.
- Kergoat H, Lovasik JV. Seven-degree head-down tilt reduces choroidal pulsatile ocular blood flow. Aviat Space Environ Med. 2005;76(10):930-934.
- Marshall-Goebel K, Ambarki K, Eklund A, et al. Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI. J Appl Physiol (1985). 2016;120(12):1466-1473.
- Federenko YF, Charapakhin KP, Yaroshenko YN, Denogratov SK. Bone density benefits with periodic fluid redistribution during diminished muscular activity in humans. Indian J Physiol Pharmacol. 2015;59(1):100-108.
- Kakuris KK, Yaroshenko YN, Charapakhin KP, Neofitov NH. Chronic head-down-tilt sleeping as physiological regulator of bone remodelling during diminished muscular activity in humans. Clin Physiol Funct Imaging. 2017;37(4):428-436.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In my last video, I noted how lying at a slight, six-degree head-down tilt for a few hours can boost fat burning. Now obviously, you wouldn’t want to lie tilted back if you had a heart condition, such as congestive heart failure. As many as eight to 12 cups (1.90 to 2.90 L) of blood may be displaced into the torso from the extremities at a tilt like that, so you have to have the cardiovascular fitness to handle it. Acid reflux could also be a problem. In fact, we typically tell heartburn patients to do the reverse—put a few bricks under the posts at the head of their bed to have gravity work in their favor to keep stomach acid down where it belongs. But for those without medical problems, is there a harm in lying tilted back for a few hours? Well, it could give you a “space headache.”
In movies, astronauts are shown practicing underwater. But the gold standard for simulating the physiological effects of the weightlessness of outer space is HDBR, head-down bed rest. On Earth, our blood tends to collect in our legs, so our body is designed to force blood headward. In outer space, our body is still trying to push our blood “up,” so without Earth’s gravity, blood pushes upwards to our head and chest––just like it does when we lie tilted back. This realization came from cosmonauts returning from the space station feeling as though they were slipping towards the foot of the bed, and only feeling “normal” when they were tilted six degrees back.
All of the extra blood pooling in the head is thought to contribute to the headaches reported by up to 70 percent of astronauts during space flights. And a similar percentage of individuals suffer headaches from prolonged head-down bed rest. That’s after days, though. In preparation for a mission to Mars, space agencies put people through head-down bed rest for prolonged periods—eating, bathing, and toileting all while lying in bed tilted back for literally months at a time.
Extended stretches of head-down positioning for weeks may impair lung function, brain function, and immune function, and cause a loss of muscle mass. On the last Apollo mission, the astronauts lost about five pounds (2.30 kg) of fat over the 12-day trip. But they also lost about two pounds (0.90 kg) of lean body mass. Prolonged weightlessness or bedrest, regardless of tilt, can result in muscle and bone loss. But just sleeping on a slant by putting a few bricks under the posts at the foot of your bed could potentially give you a boost in fat metabolism without the long-term adverse effects.
If you want to try it, a note of caution: take it slow when standing back up. After just four hours of a six-degree head-down tilt, most people experience reduced “orthostatic tolerance.” When anyone stands suddenly after sitting or lying for a while, you can get a “head rush,” feel dizzy, faint, or lightheaded as the blood drains from your brain down into your legs before your body can compensate. This can be exacerbated by lying with your head tilted back, so be careful and get up gradually. Drinking two cups (0.50 L) of cold water 30 minutes before rising may also help.
Do not try this at home if you have any heart or lung issues, or problems with your brain (like head trauma) or eyes (even a family history of glaucoma disqualifies you). Ask your physician if they think it’s safe for you to sleep in “mild Trendelenburg.” Friedrich Trendelenburg was a pioneering surgeon who popularized the use of what was formerly referred to as “head-down position” for certain abdominal and pelvic procedures. Angling the operating table back 15 to 30 degrees pulls some abdominal organs out of the way to help declutter the surgical field, resulting in what is now widely known as the Trendelenburg position.
Steep Trendelenburg (at a 25- or 30-degree tilt) has been associated with transient visual problems, thought due to the increase in pressure within the eyeball. Cautions have been issued for those at risk for glaucoma (a disease of increased eye pressure) to avoid “inversion” therapy, where people hang upside down, as well as yoga positions like handstands, which can have a similar effect.
Lying back in mild Trendelenburg, like around six degrees, can cause a fleeting bump in eye pressure that appears to normalize within a few hours. But the pooling of blood in the head may reduce blood flow to the retina sufficient to impair nerve impulses. Similar effects have been noted within the brain. Intracranial pressure also normalizes after a few hours at a six-degree head-down tilt, but the overall blood flow through the brain does drop a bit. This is why you shouldn’t try this if you have eye or brain pathology.
To my surprise, sleeping in mild Trendelenburg was actually put to the test to prevent bone loss in sedentary individuals. Restrict people’s activity to walking less than two miles (3.20 km) a day on average, and within a year they can lose as much as 15 percent of their bone mineral density. What happened to those randomized to the same exercise restriction, but also combined with sleeping at a two-degree head-down tilt that was increased by two degrees about every two months, so they ended up sleeping at a 14-degree slant (or whatever angle they felt comfortable with) by the end of the year? Not only did it completely block the bone loss, they built more bone. Despite the movement restriction, they ended up with about 12 percent greater bone mineral density than when they started. Note that this bone-building effect was only apparent in sedentary individuals. Another group randomized to the same mild Trendelenburg, but assigned to run an average of five or six miles (8 or 9.5 km) a day just maintained their same skeletal integrity.
The study was repeated, and the same remarkable effects were found. There is something about the “periodic fluid redistribution” that comes with sleeping tilted back at night that actively builds both bone density and volume after the day-long stagnant pooling of blood in the legs of sedentary individuals. The research team claims this is just the beginning to the benefits, citing “unpublished studies” asserting a near panacea of perks to sleeping in Trendelenburg. I can’t be too critical of this apparent dodge when I can’t point to a single study supporting my supposition that it will help with weight loss. As far as I can tell, it’s never been tried or even proposed. What I can promise is that any researchers who take on the mantle of putting it to the test will definitely have their study featured in a video on NutritionFacts.org.
Please consider volunteering to help out on the site.
- Moro C, Pillard F, de Glisezinski I, et al. Atrial natriuretic peptide contribution to lipid mobilization and utilization during head-down bed rest in humans. Am J Physiol Regul Integr Comp Physiol. 2007;293(2):R612-617.
- Lathers CM, Diamandis PH, Riddle JM, et al. Acute and intermediate cardiovascular responses to zero gravity and to fractional gravity levels induced by head-down or head-up tilt. J Clin Pharmacol. 1990;30(6):494-523.
- Albarqouni L, Moynihan R, Clark J, Scott AM, Duggan A, Del Mar C. Head of bed elevation to relieve gastroesophageal reflux symptoms: a systematic review. BMC Fam Pract. 2021;22(1):24.
- van Oosterhout WPJ, Terwindt GM, Vein AA, Ferrari MD. Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity. Cephalalgia. 2015;35(4):335-343.
- Bareille MP, Maillet A. Human: bed rest/head-down-tilt/hypokinesia. In: Generation and Applications of Extra-Terrestrial Environments on Earth. 1st ed. River Publishers; 2022:133-145.
- "Montmerle S, Spaak J, Linnarsson D. Lung function during and after prolonged head-down bed rest. J Appl Physiol. 2002;92(1):75-83. "
- "Liu Q, Zhou R, Chen S, Tan C. Effects of head-down bed rest on the executive functions and emotional response. PLoS One. 2012;7(12):e52160. "
- Kelsen J, Bartels LE, Dige A, et al. 21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog. Cytokine. 2012;59(2):403-409.
- Ritz P, Acheson KJ, Gachon P, et al. Energy and substrate metabolism during a 42-day bed-rest in a head-down tilt position in humans. Eur J Appl Physiol Occup Physiol. 1998;78(4):308-314.
- Johnson PC, Leach CS, Rambaut PC. Estimates of fluid and energy balances of Apollo 17. Aerosp Med. 1973;44(11):1227-1230.
- Krebs JM, Schneider VS, Evans H, Kuo MC, LeBlanc AD. Energy absorption, lean body mass, and total body fat changes during 5 weeks of continuous bed rest. Aviat Space Environ Med. 1990;61(4):314-318.
- Butler GC, Xing HC, Northey DR, Hughson RL. Reduced orthostatic tolerance following 4 h head-down tilt. Eur J Appl Physiol Occup Physiol. 1991;62(1):26-30.
- Figueroa JJ, Basford JR, Low PA. Preventing and treating orthostatic hypotension: as easy as A, B, C. Cleve Clin J Med. 2010;77(5):298-306.
- Martin JT. The Trendelenburg position: a review of current slants about head down tilt. AANA J. 1995;63(1):29-36.
- Halm MA. Trendelenburg position: “put to bed” or angled toward use in your unit? Am J Crit Care. 2012;21(6):449-452.
- Taketani Y, Mayama C, Suzuki N, et al. Transient but significant visual field defects after robot-assisted laparoscopic radical prostatectomy in deep trendelenburg position. PLoS One. 2015;10(4):e0123361.
- Friberg TR, Sanborn G. Optic nerve dysfunction during gravity inversion. Pattern reversal visual evoked potentials. Arch Ophthalmol. 1985;103(11):1687-1689.
- Cramer H, Krucoff C, Dobos G. Adverse events associated with yoga: a systematic review of published case reports and case series. PLoS One. 2013;8(10):e75515.
- Linder BJ, Trick GL, Wolf ML. Altering body position affects intraocular pressure and visual function. Invest Ophthalmol Vis Sci. 1988;29(10):1492-1497.
- Marshall-Goebel K, Mulder E, Bershad E, et al. Intracranial and intraocular pressure during various degrees of head-down tilt. Aerosp Med Hum Perform. 2017;88(1):10-16.
- Kergoat H, Lovasik JV. Seven-degree head-down tilt reduces choroidal pulsatile ocular blood flow. Aviat Space Environ Med. 2005;76(10):930-934.
- Marshall-Goebel K, Ambarki K, Eklund A, et al. Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI. J Appl Physiol (1985). 2016;120(12):1466-1473.
- Federenko YF, Charapakhin KP, Yaroshenko YN, Denogratov SK. Bone density benefits with periodic fluid redistribution during diminished muscular activity in humans. Indian J Physiol Pharmacol. 2015;59(1):100-108.
- Kakuris KK, Yaroshenko YN, Charapakhin KP, Neofitov NH. Chronic head-down-tilt sleeping as physiological regulator of bone remodelling during diminished muscular activity in humans. Clin Physiol Funct Imaging. 2017;37(4):428-436.
Motion graphics by Avo Media
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Title
The Risks and Benefits of Mild Trendelenburg Position to Reduce Body Fat
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
If you missed the previous video, check out Lying at a Slight Head-Down Tilt (Trendelenburg Position) to Burn Fat.
What about brown fat? See Brown Fat: Losing Weight Through Thermogenesis and Boosting Brown Fat Through Diet.
My book How Not to Diet is all about optimal weight loss. Check it out at your local library. It’s available in print, e-book, and audio. (All proceeds I receive from the book are donated directly to charity.)
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