We recommend that all ME/CFS and Fibromyalgia patients have a NASA 10-minute Lean Test to assess for orthostatic intolerance. Batetman Horne Center

The saga of the effort to introduce and validate the NASA Lean Test (NLT) for ME/CFS just seems so right in so many ways. First the Bateman Horne Center identified a test – from NASA no less –  that can easily be used to identify orthostatic intolerance (symptoms when standing).

Then they enrolled a large number of patients, got researchers involved, validated the test, and in doing so, learned something new about ME/CFS in the process. It’s taken years to get through all this – but in the end, it provides something that’s really needed – an easy test to identify orthostatic intolerance (OI) and get doctors engaged in treating ME/CFS as a biological phenomena they can help with.

The NASA Lean Test, validated by the Bateman Horne Center, is easy – and requires just two simple instruments already found in doctors’ offices. (Image from the Bateman Horne Center)

Orthostatic intolerance refers to the inability to stand without symptoms. Although most of us are completely unaware of it, successful standing up requires an array of processes to work properly.

The minute you stand, gravity wants to force your blood downwards into your legs. In order to blunt that, the skeletal muscle pump constricts the blood vessels in your legs, increases pressure in the abdomen, causes a bit of swaying, decreases parasympathetic nervous system activity and activates the sympathetic nervous system.

The blood pressure at your arm momentarily drops as your blood starts to flow downwards, but then should bound back up as baroreceptors in the blood vessels tell your heart to beat faster. All this occurs automatically and below the level of consciousness.

When things go wrong with that system, orthostatic intolerance occurs and many different kinds exist. Postural orthostatic tachycardia syndrome (POTS) and its subsets (post-viral POTS, hyperadrenergic POTS, neuropathic POTS, hypo/hyperkinetic, exercise-induced POTS) appear to be the most common form of OI found in ME/CFS. Other forms of OI (orthostatic hypotension (OH), neurally mediated hypotension (neurogenic orthostatic hypotension) exist and, in this still rather new field, new forms of OI are still popping up.

Tilt tables have traditionally been used to assess OI but many medical practices don’t have access to them. The NASA Lean Test, on the other hand, can be done using the tools found in a doctor’s office. It requires only three things: an exam table, a pulse oximeter (placed on one hand), and a blood pressure cuff (placed on the opposite arm).

First, the person rests lying down for 10 minutes, then she/he stands up, and with her/his heels 6-8 inches from the wall, and shoulder blades touching it, stays there for ten minutes (or until it’s clear they have OI). Heart rate, blood pressure and symptoms are recorded. Just as the tilt table test does, the NLT removes the skeletal muscle pump action from the equation. You, your baroreceptors, your heart, and your autonomic nervous system are on your own.

J Transl Med. 2020 Aug 15;18(1):314. doi: 10.1186/s12967-020-02481-y.Hemodynamics during the 10-minute NASA Lean Test: evidence of circulatory decompensation in a subset of ME/CFS patients. Jihyun Lee 1Suzanne D Vernon 2Patricia Jeys 1Weam Ali 1Andrea Campos 1Derya Unutmaz 3Brayden Yellman 1Lucinda Bateman 1

The large Lee-Bateman study (150 ME/CFS and 75 healthy controls) from the Bateman Horne Center consisted of ME/CFS patients who fulfilled the International Chronic Fatigue Syndrome Study Group research criteria (aka Fukuda), the Canadian Consensus Criteria (aka CCC), and the IOM clinical diagnostic criteria.

fibromyalgia POTS

Many people don’t associated FM with orthostatic intolerance, but it is one of its comorbid conditions. Although the study was on ME/CFS, Dr. Bateman clearly states the NASA Lean Test should be used in both ME/CFS and FM. (Image from Wikimedia – https://commons.wikimedia.org/wiki/File:Fibromyalgia_and_comorbid_conditions.jpg)

All the participants benefitted from the Bateman Horne Center’s extremely thorough approach which included answering an astounding number of questionnaires (DePaul Symptom Questionnaire, Post-Exertional Fatigue Questionnaire, RAND-36, Fibromyalgia Impact Questionnaire-R, ACR 2010 Fibromyalgia Criteria Symptom Questionnaire, Pittsburgh Sleep Quality Index, Stanford Brief Activity Survey, Orthostatic Intolerance Daily Activity Scale, Orthostatic Intolerance Symptom Assessment, Brief Wellness Survey, Hours of Upright Activity, medical history and family history.

Besides heart rate and blood pressure, something called pulse pressure was measured as well. Pulse pressure is the difference between systolic and diastolic blood pressure. It represents the stroke volume – the volume of blood ejected by the heart when it beats.

Two kinds of orthostatic intolerance were assessed:

Orthostatic hypotension (OH) (lowered blood pressure upon standing) was defined as a decrease in systolic blood pressure (SBP) 20 mm Hg or more, or a decrease in diastolic blood pressure (DBP) of 10 mm Hg or more in the first 3 minutes.

Postural orthostatic tachycardia syndrome (POTS) was defined as a heart rate increase of >30 beats per minute (bpm) upon standing or a heart rate of greater than 120 bpm.


Duration Matters – Less is not More

Time matters – this study validated the results of another tilt table study which indicated that the 1-3 minute orthostatic assessment typically carried out in doctors’ offices isn’t enough. Even a 2-5 minute tilt table test will miss a considerable set of POTS patients.

The Lee-Bateman study found that at least 5 minutes of the NASA lean test are necessary to pick up signs of orthostatic intolerance in most of the participants and a full ten minutes are needed to pick up more.

Interlude – the Plash study – More Can Be Tricky

The Gist

  • Many people with ME/CFS or FM who have orthostatic intolerance  (OI) ( their symptoms worsen upon standing) do not have access to the tilt table tests usually used to diagnose OI
  • The Bateman Horne Center produced a study designed to assess the ability of a simple test called the 10-minute NASA Lean Test (NLT) which can easily be done in a doctor’s office.
  • The NLT requires that patients stand with their backs to the wall with their heels 6-8 inches from the wall and shoulders touching the wall.
  • The study found that about 40% of the ME/CFS patients meet the criteria for either postural orthostatic tachycardia syndrome (POTS) or orthostatic hypotension.
  • It also found that the NLT test needs to be done for at least 5 minutes to get good results; 10 minutes is better.
  • Because a significant percentage of healthy people who do not have orthostatic intolerance can test positive on the test, a diagnosis of OI requires that participants also experience symptoms while taking the test.
  • The ME/CFS participants in the study experienced many more symptoms than the healthy controls. Their heart rate, blood pressure and pulse pressure readings were also significantly worse.
  •  Pulse pressure  is an analog for stroke volume – the amount of the blood the heart emits when it beats. The low pulse pressure in the ME/CFS patients reflected reduced blood flows to the heart.
  • David Systrom at Harvard found reduced blood flows to the heart  (reduced preload) in his large study of people with exertion intolerance.  He believes that microcirculatory issues that shunt blood into the interstitial spaces of the muscles may be robbing the heart of the blood it usually receives.
  • People with shorter cases of ME/CFS (<4 years) were actually worse off. The authors believed that the systems longer duration patients may have created some compensatory mechanisms that may have helped.
  • Diagnosing orthostatic intolerance in the doctor’s office could provide many people with ME/CFS and/or FM will treatments that help.
  • The Bateman Horne Center believes everyone with ME/CFS or FM should have the NASA Lean Test done

In 2013, Plash also found that test duration matters. Everyone’s physiology, whether healthy or not, starts to suffer after being tilted or being forced to stand for awhile.

Plash found out that while the 10-minute Tilt Table Test correctly identified 93% of the all POTS patients (high sensitivity), it also incorrectly identified 60% of the healthy controls as having POTS (!) (low specificity). After 30 minutes of the tilt table test, things were considerably worse: 80% of  the healthy controls were incorrectly identified as having POTS.

The Lee/Bateman study found the same. At the end of ten minutes, 33% of healthy controls meet the criteria for POTS (increase of <30 bpm). (Forty percent of the people with ME/CFS did.)

The issue arises because even the heart rates of healthy people tend to increase over time when they are tilted. Plash suggested that at the 10 minute mark, the criteria for having POTS should be increased from 30 bpm to 37 bpm, and at the 30 minute mark, to 47 bpm.

Note that even using this stiffened criteria, the tests were not completely accurate; i.e. they still falsely identified from 20-27% of healthy controls as having POTS. This isn’t much of an issue for people with ME/CFS/FM with orthostatic intolerance issues (symptoms increase upon standing or after standing for awhile, but it’s interesting that some healthy people – and probably not a few – have POTS-like increased heart rates upon standing. For some reason, they don’t suffer from POTS.

The issue also makes clear that increased heart rates by themselves don’t necessarily produce POTS. It’s a multidimensional illness – some aspects of which we clearly don’t know much about.

Plash concluded that POTS should only be identified in people with symptoms of orthostatic intolerance and high heart rates on a TILT or standing test like the NASA Lean Test (NLT). The Bateman Horne Center concludes the same – high heart rates during the NLT are only diagnostic for POTS if they are accompanied by symptoms as well.

Symptoms, however, were not hard to find in the chronic fatigue syndrome (ME/CFS) group. The test provoked far more symptoms in the people with ME/CFS patients – even in those without POTS (see below) – than it did in the healthy controls.

“Pathologic” Drops in Pulse Pressure

The ME/CFS group also has worse cardiovascular scores. While both groups’ heart rates increased over time, the heart rates of the ME/CFS group started out higher (that high baseline heart rate issue) and went up faster. In fact, every measured test result (blood pressure/ heart rate/ pulse pressure) was worse in the ME/CFS patients than the healthy control group.

Higher heart rates (both resting and standing) and “pathologic” drops in pulse pressure particularly distinguished the ME/CFS patients from the healthy controls.

The “striking finding” of the very abnormally narrowed pulse pressure in shorter duration ME/CFS patients (<4 years) appears to have reflected a reduced stroke volume; i.e. reduced blood outflows from the heart. That is usually the result of a heart problem, but studies suggest the heart in ME/CFS is generally fine. Instead, the authors asserted that narrowed pulse pressure was almost certainly caused by reduced blood inflows to the heart.

That ties in nicely with what Systrom found (reduced preload) in his invasive exercise study. Systrom believes several things may be in play, including microcirculatory problems which are reducing blood flows to the venous system (the left to right shunt) causing less blood to be available to the heart.

The Exercise Intolerance in POTS, ME/CFS and Fibromyalgia Explained?

Newbies Are the Worst Off

Interestingly, the more recently a person came down with ME/CFS, the worse off they were. The relative newbies – those who have been ill for less than 4 years – had the worst drops in pulse pressure, followed by those who had had ME/CFS for over ten years.

Why would people newer to ME/CFS have worse problems than those who had it longer? Perhaps because some sort of compensatory approach over time been developed. The autonomic nervous system can be trained and it can apparently adapt to some extent. My symptoms were certainly worse in the beginning.

Orthostatic Intolerance Without POTS or Orthostatic Hypotension

That study also found that even ME/CFS patients who didn’t meet the criteria for either POTS or orthostatic hypotension still experienced significantly more symptoms during the NLT than did the healthy controls. Somehow, they too were getting whacked by having to lean up against a wall for ten minutes. That finding reminds us that the field of orthostatic intolerance is relatively new, surprises are in store, and that POTS or OH isn’t everything.

The field is also growing and the authors were able to point quickly to a 2020 study by Van Campen and Visser, which found that even ME/CFS patients without POTS or orthostatic hypotension still experienced reduced blood flows to the brain during a tilt test.

I may have experienced something like this during a twin study about 15 years ago. Both my twin and I “passed” the tilt table test, but I was miserable throughout and remained symptomatic for some time afterwards. He, on the other hand, experienced no symptoms at all.

The Visser study followed a 2018 study by Peter Novak, who also uncovered a group of patients without POTS or any other sign of OI, but nevertheless had reduced blood flows to the brain. Novak uncovered this group after he kept getting “POTS” patients who didn’t end up having POTS. What they did have were low CO2 levels. Novak called this new form of orthostatic intolerance hypocapnic cerebral hypoperfusion.

Novak suggested a number of possible causes (baroreceptor problems, metabolic acidosis, orthostatic ventilation-perfusion mismatch, problems with the respiratory centers in the brain) and was planning to dig deeper. Since this is probably not a small group, and since it’s clear that it’s abundant in ME/CFS, further investigations into this group are going to be fascinating.

Hypocapnic Cerebral Hypoperfusion: New Kind of Orthostatic Intolerance Points to Key Factor in ME/CFS and Others

If you’ve been disappointed when your non-POTS diagnosis failed to capture your brain fog, standing problems, etc. – be disappointed no more. There are clearly other ways to mess up your brain when you stand than by having a fast heart rate or a balky blood pressure adjustment system.


While the study didn’t provide treatment recommendations, many treatment options exist. That’s good news for you and your doctor. On the one hand, seeing your doctor may actually help you to get better (woo-woo). On the other, your doctors get to do what they got into their profession to do – help you. Maybe they’ll even get more interested in ME/CFS or FM.

The symptoms associated with orthostatic intolerance closely resemble those found in ME/CFS and FM, and include lightheadedness (occasionally with fainting), difficulty thinking and concentrating (brain fog), fatigue, intolerance of exercise, headache, blurry vision, palpitations, tremor and nausea.

From doing things like increasing salt intake to increasing blood volume, to wearing compression stockings, to drugs, to recumbent exercises (for those who can handle them), many options are available for people with OI.

Check out some videos from the Bateman Horne Center on how to diagnose and treat orthostatic intolerance:



The main finding was that many cases of orthostatic intolerance can now be diagnosed in a doctor’s office using the simple tools embedded in the NASA Lean Test. All a doctor needs to do is assess symptoms, heart rate and blood pressure for ten minutes. Orthostatic intolerance is diagnosed when the following guidelines are met – in the presence of symptoms:

  • Orthostatic hypotension (OH) – (lowered blood pressure upon standing)  – a decrease in systolic blood pressure (SBP) 20 mm Hg or more, or a decrease in diastolic blood pressure (DBP) of 10 mm Hg or more in the first 3 minutes.
  • Postural orthostatic tachycardia syndrome (POTS) -a heart rate increase of >30 beats per minute (bpm) upon standing or a heart rate of greater than 120 bpm.

Health Rising has a ‘how to’ for the NASA Lean Test from Dr. Lucinda Bateman here. Note that the test is most revealing if the patient:

  • Limits water/fluid intake to 1000 mL for 24 hours before the test
  • Limits sodium intake for 48 hours before the test
  • Does not wear compression socks or compression clothing on the day of the test
  • Withholds medications, supplements, or substances that might affect blood pressure or heart rate, with timing based on the drug half-life and patient safety. (See the post for the list.)

The study also revealed that tests for OI must be at least five minutes long, that orthostatic intolerance can only be diagnosed in people with symptoms of it, that some healthy people have high POTS-like heart rates, that the orthostatic intolerance in people who are relatively new to ME/CFS (<4 yrs) is worse, and it suggested that Systrom’s findings of reduced preload or blood flows to the heart are accurate. That suggests problems with the microcirculation are losing blood somewhere along the the way.

The study found that about 40% of the ME/CFS patients tested positive for orthostatic intolerance, but a recent Visser study found that over 80% of ME/CFS patients who did not meet the criteria for orthostatic intolerance still had reduced blood flows to the brain. Not testing positive for POTS or orthostatic hypotension does not mean you don’t have orthostatic intolerance. You could, for instance, have the new form of OI uncovered by Novak – hypocapnic cerebral hypoperfusion. There is clearly more learn about OI.

  • Coming up – a cheap and effective replacement for saline?
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