Part 2 of 6 in the "always tired" series; the other five are listed at the foot.
You have heard 「气虚」 and 「血虚」, but nobody has said what those two words actually refer to — that is the gap this part fills.
Everything below is TCM theory, with the definitions taken from the WHO's 2022 standard terminology. The standard's use here is specific: it makes every line checkable.
The short version
- The standard describes qi as the intangible, high-mobility nutritive substance that maintains vital activities.
- It describes blood as the red liquid that circulates within the blood vessels to moisten and nourish the body — an essential substance to maintain life activities.
- Both definitions are written in terms of what the thing does — so 「血」 in the theory is about a function, not a quantity a blood test can measure.
- Three further entries cover the spleen governing transportation and transformation, the postnatal foundation, and qi engendering blood. Chained together they put qi and blood downstream of food by way of the spleen — and that chaining is this article's sentence, not the standard's.
- In the standard, 「气虚」 is a pathological state; 「气虚证」 is a category a practitioner reaches after assessment. The same presentations can point to different patterns, so it is not a self-test label.
First, the things that cannot wait
Weight loss you did not intend, or breathlessness, palpitations or chest tightness alongside it — see a doctor for investigation first. The NHS states each separately: it is important to get it checked if you are losing weight without trying, and sometimes the cause can be cancer; and palpitations can be caused by a condition such as iron deficiency anaemia or an overactive thyroid (hyperthyroidism).
Persistently low mood, loss of interest, or thoughts of harming yourself — call 999 now, or go to the nearest hospital emergency department. To talk to someone, the Ministry of Health's Talian HEAL 15555 is open every day from 8 am to 12 midnight, public holidays included [KKM-HEAL]; Befrienders KL is open 24 hours on 03-7627 2929 [BEF]. You can also contact your doctor.
The full list, and the reason for each, are in part 5. TCM and Western medicine complement each other; it is not a choice between them.
A note: this section is general information only. For conditions like these, follow your doctor's diagnosis and treatment, and seek medical attention when you need it.
I. Two words defined first
Qi (气), in the standard's words: the intangible, high-mobility nutritive substance that maintains vital activities.
Blood (血), in the standard's words: the red liquid that circulates within the blood vessels to moisten and nourish the body — an essential substance to maintain life activities.
Notice how both are written: each is defined by what it does — maintaining vital activities, moistening and nourishing the body. 「血」 in the theory is about a function, not a quantity a blood test can measure.
That matters, because the same character 血 means something else on a blood report. Setting the two languages side by side is part 3.
💡 Remember: 「气」 and 「血」 in the theory are defined by function, not by quantity.
II. Where qi and blood come from, in the theory
Three entries in the standard each say one piece of this:
The spleen governs transportation and transformation (脾主运化). The spleen digests water and food, absorbs and distributes nutrients, and regulates water metabolism.
Postnatal foundation (后天之本) refers to the spleen: the spleen transports and transforms nutrients from water and food, the essential material foundation to maintain vital activities.
Qi engenders blood (气能生血). Qi can transform into blood; blood is transformed from nutrients from water and food and ying-nutrient qi within the blood vessels.
Put the three together: in the theory's model, both qi and blood come from food, by way of the spleen's transportation and transformation. That sentence is this article's summary of the three definitions above, not the standard's own words — no single entry states that qi comes from food.
The chaining has one practical consequence. It is why the consultation in part 6 asks a tired person about appetite, how they feel after meals and bowel habit — in the theory, that is where qi and blood come from. It is also why one of the three category names in the next section carries the word 「脾」 (spleen).
III. 「气虚」 is a pathological state; 「气虚证」 is a category
These two get used interchangeably, and separating them clears up a great deal.
The state first. The standard describes qi deficiency (气虚) as a pathological state of decreased zang-fu functions or body weakness due to deficiency of qi. It describes blood deficiency (血虚) as a pathological state in which deficient blood fails to nourish the zang-fu organs and meridians.
Then the category. After a consultation, the practitioner may place the tiredness under a pattern. The same standard lists three that are relevant here:
- Qi deficiency pattern (气虚证) — its description mentions: often results from hypofunctions of the zang-fu organs.
- Blood deficiency pattern (血虚证) — its description mentions: often occurs when blood fails to nourish the zang-fu organs, meridians and other body tissues.
- Spleen deficiency with dampness pattern (脾虚湿困证) — its description mentions: often results from internal retention of turbid dampness due to spleen qi deficiency.
These three are the practitioner's categories after assessment — not a self-test, and not the whole list; the standard holds far more patterns than these. The same kind of tiredness can point to different patterns in the theory, and which one applies is decided after seeing the whole picture. Why a pattern name is a category rather than a cause is part 3, which starts from the standard's definition of a pattern.
And the packet marketed as "qi-boosting"? From the above, whether 「气虚」 applies is a judgement made after seeing the whole picture. So a supplement marketed as "qi-boosting" from a direct-sales friend or from family goes to the consultation: describe the contents and where it came from, and show it. The same holds for prescribed medication and for over-the-counter products from a pharmacy. Doing this safely depends on both sides knowing. Never stop prescribed medication on your own. On taking Chinese herbs alongside Western medication, see: can Chinese herbs be taken with Western medicine.
💡 Remember: 「气虚」 names a state; 「气虚证」 is the category a practitioner gives after seeing the whole picture — and neither is a label for you to match against yourself.
The words in this part
All five come from the WHO's TCM terminology standard.
- Qi (气) — the intangible, high-mobility nutritive substance that maintains vital activities. That is the standard's description.
- Blood (血, xuè) — the red liquid that circulates within the blood vessels to moisten and nourish the body, an essential substance to maintain life activities. Note that it is defined by function.
- The spleen governs transportation and transformation (脾主运化) — the spleen digests water and food, absorbs and distributes nutrients, and regulates water metabolism. This entry is the root of the appetite and bowel questions at a consultation.
- Postnatal foundation (后天之本) — refers to the spleen: the spleen transports and transforms nutrients from water and food, the essential material foundation to maintain vital activities.
- Qi deficiency (气虚) / qi deficiency pattern (气虚证) — the first is a pathological state of decreased zang-fu functions or body weakness due to deficiency of qi; the second is a pattern name whose description mentions it often results from hypofunctions of the zang-fu organs. You may hear the second one at a consultation.
Frequently asked
Is the TCM "qi deficiency" just another word for tired? They are not the same kind of word. "Qi deficiency pattern" is the name of a pattern in TCM theory, and the WHO standard's description mentions that it often results from hypofunctions of the zang-fu organs. "Tired" is a presentation; after a consultation, the practitioner may place it under the qi deficiency pattern, the blood deficiency pattern, spleen deficiency with dampness, or another pattern — or under none of them. It is not a self-label.
Can I start the "qi tonic" a relative gave me? Better to raise it at the consultation first. This part covers what 「气」 means inside the theory, not which product suits whom — that belongs to an individual assessment. Bring the contents and the source to the consultation and show them, and say what medication you are taking; never stop prescribed medication on your own because you are going to see a TCM practitioner.
The other five parts
- Part 1: First, which kind of tired; then what a blood test can tell you
- Part 3: 「血虚」 is not anaemia — one is a category, the other a number
- Part 4: Setting your routine: TCM theory's position beside the public-health numbers
- Part 5: When to see a doctor first — each sign, and what it can indicate
- Part 6: What a consultation actually does, and the seven-day log to bring
👉 If you are not sure whether somebody calling you "qi deficient" has anything to do with you, you are welcome to book an online consultation with HansMed, where a practitioner registered under the T&CM Act 2016 can assess it with you; if anything in "First, the things that cannot wait" above or in part 5 applies, see a doctor first.
Sit with a licensed TCM practitioner from wherever you are.
HansMed Modern TCM
For general wellness education only — not medical advice. Consult a registered TCM practitioner for personal guidance.
Sources
- World Health Organization, WHO international standard terminologies on traditional Chinese medicine, 2022 — https://www.who.int/publications/i/item/9789240042322
- NHS, Unintentional weight loss, page last reviewed 28 July 2025 — https://www.nhs.uk/symptoms/unintentional-weight-loss/
- NHS, Heart palpitations, page last reviewed 17 March 2026 — https://www.nhs.uk/symptoms/heart-palpitations/
- Ministry of Health Malaysia, Hospital Pendang (Kedah State Health Department), Info Kesihatan 2024 — https://jknkedah.moh.gov.my/hpendang/index.php?option=com_sppagebuilder&view=page&id=139
- Befrienders Kuala Lumpur — https://www.befrienders.org.my/
