低下する in 30 Seconds
- Formal verb for 'decline' or 'drop'.
- Used for quality, ability, and function.
- Common in news, medicine, and business.
- Intransitive: [Subject] ga teika suru.
The Japanese verb 低下する (ていかする - teika suru) is a formal and versatile term used to describe a decline, drop, or deterioration in level, quality, value, or functionality. Unlike simple verbs like sagaru (to go down), teika suru carries a more technical or academic nuance, often implying that something which was once at a higher or optimal state has moved to a lower, less desirable state. It is composed of two kanji: 低 (low) and 下 (down), literally translating to 'becoming low and going down'.
- Functional Decline
- Used when organs, machines, or systems lose their efficiency. For example, kinou no teika (decline in function).
- Qualitative Deterioration
- Refers to a drop in standards, such as hinshitsu no teika (drop in quality) or service no teika.
- Numerical or Level Drop
- Applied to abstract levels like gakuryoku (academic ability) or shiryo (vision/eyesight).
「加齢に伴い、身体機能が徐々に低下するのは避けられない現象です。」
(It is an unavoidable phenomenon that physical functions gradually decline with age.)
In economic contexts, it is frequently paired with terms like bukka (prices) or shohi (consumption), though geraku is more common for stock prices. The word implies a negative progression or a loss of vitality. It is a 'suru-verb', meaning it functions as a noun (低下 - decline) that becomes an intransitive verb when combined with suru.
「景気の悪化により、国民の生活水準が低下している。」
(Due to the economic downturn, the people's standard of living is declining.)
- Subjectivity
- It is objective. It describes a measurable or observable drop rather than an emotional feeling of 'feeling down'.
Using 低下する correctly requires understanding its role as an intransitive verb. It describes a state change where the subject itself goes down. The basic structure is: [Subject] + が + 低下する.
- Formal Reports: Used in medical, academic, and business writing to show data trends.
- Health & Biology: Describing vision, hearing, immune systems, or organ efficiency.
- Societal Trends: Describing birth rates, academic standards, or public safety.
「スマートフォンの使いすぎで、視力が低下してしまった。」
(My eyesight has declined because I used my smartphone too much.)
Grammatically, it can be used in various forms: teika shite iru (is declining/has declined), teika sasera (to cause to decline - causative), or teika ga mirareru (a decline is observed). It is rarely used in the passive voice because the decline is usually a natural or systemic process rather than an action performed by an agent on the subject.
- Example: Rapid Decline
- 急激に機能が低下する (Functions decline rapidly).
- Example: Gradual Decline
- 徐々に能力が低下する (Abilities decline gradually).
You will encounter 低下する in environments where precision and formality are valued. It is a staple of NHK news broadcasts, scientific journals, and corporate performance reviews.
1. Medical and Health Contexts
Doctors use it to describe a patient's condition. Men'eki-ryoku no teika (decline in immunity) is a common phrase during flu season or when discussing chronic stress.
「最近、集中力が低下していると感じることはありませんか？」
(Have you felt lately that your ability to concentrate is declining?)
2. Economic and Business News
When discussing the 'purchasing power' (koubairyoku) of the yen or the 'productivity' (seisansei) of a company, teika is the standard term. It sounds objective and data-driven.
3. Technical Manuals
In IT or engineering, if a battery's capacity drops or a signal weakens, teika is used. Denchi no seino ga teika suru (Battery performance declines).
While 低下する means 'to decrease', it is not interchangeable with every 'down' word in Japanese. Here are the most frequent errors learners make:
- Mistake 1: Using it for physical movement
- You cannot say hikouki ga teika suru for a plane descending. Use koka suru (descend) or sagaru.
- Mistake 2: Confusing with 減少 (Genshou)
- Genshou is for quantity/number (e.g., population). Teika is for quality/level/degree (e.g., quality). You don't 'teika' the number of apples; you 'genshou' them.
❌ 人口が低下する (Incorrect)
✅ 人口が減少する (Correct - Population decreases)
✅ 生活の質が低下する (Correct - Quality of life declines)
Japanese has many words for 'down'. Understanding the nuances helps you sound more natural.
- 下がる (Sagaru)
- The general, everyday word. Used for temperature, prices, or physical height. Teika is the formal version of this for abstract levels.
- 減少する (Genshou suru)
- Specifically for numbers, amounts, or counts. If you can count it (1, 2, 3), use genshou.
- 衰退する (Suitai suru)
- To decline or decay over a long period, often used for civilizations, industries, or towns. Much stronger and more permanent than teika.
- 悪化する (Akka suru)
- To worsen. While teika is a drop in level, akka emphasizes that the situation is becoming 'bad' or 'dangerous'.
「品質が低下する」(Quality drops) vs 「品質が悪化する」(Quality gets worse/rotten).
How Formal Is It?
Difficulty Rating
Grammar to Know
～に伴い (ni tomonai - along with)
～によって (ni yotte - due to)
～恐れがある (osore ga aru - fear that)
～つつある (tsutsu aru - in the process of)
～させる (saseru - causative)
Examples by Level
テストの点が低下しました。
Test scores declined.
Polite past tense of teika suru.
元気が低下しています。
Energy is declining.
Te-iru form showing current state.
スピードが低下する。
Speed decreases.
Dictionary form.
気温が低下しました。
The temperature dropped.
Formal version of 'sagaru'.
やる気が低下する。
Motivation declines.
Common abstract subject.
質が低下した。
The quality declined.
Short past tense.
能力が低下する。
Ability declines.
Standard usage.
機能が低下しています。
Functions are declining.
Continuous state.
最近、視力が低下してきた。
Recently, my eyesight has started to decline.
Te-kuru indicates a change starting to happen.
学力の低下が問題です。
The decline in academic ability is a problem.
Teika used as a noun.
この薬は血圧を低下させる。
This medicine lowers blood pressure.
Causative form (teika saseru).
サービスの質が低下している。
The quality of service is declining.
Progressive state.
注意力が低下しやすい時間です。
It's a time when attention tends to decline.
Masu-stem + yasui (easy to/tends to).
生産性が低下してしまった。
Productivity has unfortunately declined.
Te-shimau indicates regret.
免疫力が低下すると病気になる。
When immunity declines, you get sick.
Conditional 'to'.
記憶力が低下したと感じる。
I feel like my memory has declined.
Verb + to kanjiru (feel that...).
不況により、国民の購買力が低下している。
Due to the recession, the purchasing power of the citizens is declining.
Formal economic context.
運動不足は筋力の低下を招く。
Lack of exercise leads to a decline in muscle strength.
Teika (noun) + wo maneku (to lead to/invite).
品質管理を怠ると、信頼が低下する。
If you neglect quality control, trust will decline.
Conditional 'to' with abstract noun.
高齢化社会では、労働力が低下する恐れがある。
In an aging society, there is a fear that the labor force will decline.
Osore ga aru (there is a fear/risk that...).
スマートフォンの普及で、読解力が低下したと言われている。
It is said that reading comprehension has declined due to the spread of smartphones.
Passive reporting 'to iwarete iru'.
ストレスは胃の機能を低下させる原因になる。
Stress becomes a cause for the decline of stomach function.
Causative used as a noun phrase.
円の価値が急激に低下した。
The value of the yen declined sharply.
Adverb 'kyugeki ni' (sharply).
睡眠不足で集中力が低下し、ミスが増えた。
Due to lack of sleep, concentration declined and mistakes increased.
Compound sentence with 'te-form' for cause.
新薬の副作用により、肝機能が低下する可能性がある。
There is a possibility that liver function will decline due to the side effects of the new drug.
Kan-kinou (liver function) + teika.
ブランドイメージの低下を避けるため、迅速に対応した。
To avoid a decline in brand image, they responded quickly.
Teika (noun) + wo yokeru (to avoid).
教育水準の低下が、将来の経済成長を阻害する。
The decline in educational standards hinders future economic growth.
Subject is a complex noun phrase.
過度なダイエットは代謝の低下を招き、逆効果だ。
Excessive dieting leads to a decline in metabolism and is counterproductive.
Taisha (metabolism) + teika.
情報の正確性が低下すると、メディアの価値が失われる。
When the accuracy of information declines, the value of the media is lost.
Seikakusei (accuracy) + teika.
建物の老朽化に伴い、耐震性が低下している。
As the building ages, its earthquake resistance is declining.
Ni tomonai (along with/as...).
競争の激化により、利益率が低下傾向にある。
Due to intensifying competition, profit margins are on a downward trend.
Teika keikou (downward trend).
汚染によって、土壌の質が著しく低下した。
The quality of the soil has declined remarkably due to pollution.
Ichijirushiku (remarkably/strikingly).
認知機能の低下を早期に発見することが、認知症治療において重要だ。
Early detection of declining cognitive function is crucial in dementia treatment.
Ninchi-kinou (cognitive function).
市場の飽和に伴い、製品の付加価値が低下しつつある。
With market saturation, the added value of products is in the process of declining.
Tsutsu-aru (in the process of doing...).
政治への無関心が、民主主義の質を低下させている。
Indifference to politics is causing the quality of democracy to decline.
Causative form describing a societal cause-effect.
通信環境の悪化により、データの転送速度が低下した。
Due to the worsening communication environment, data transfer speeds declined.
Technical context.
組織の硬直化は、創造性の低下に直結する。
The rigidification of an organization directly leads to a decline in creativity.
Chokketsu suru (to be directly linked).
労働条件の悪化は、従業員のモチベーションを著しく低下させる。
Worsening working conditions remarkably lower employee motivation.
Formal causative structure.
森林破壊は、生物多様性の低下を加速させている。
Deforestation is accelerating the decline in biodiversity.
Kasoku saseru (to accelerate).
倫理観の低下が、社会全体の腐敗を招いている。
The decline in ethical values is leading to corruption throughout society.
Rinrikan (ethical values).
限界効用の低下という経済学的概念は、消費行動を説明する鍵となる。
The economic concept of diminishing marginal utility is key to explaining consumer behavior.
Genkai kouyou (marginal utility).
言語の画一化は、文化的な多様性の低下を意味するのではないか。
Doesn't the standardization of language signify a decline in cultural diversity?
Rhetorical question in formal essay style.
神経伝達物質の分泌低下が、抑うつ状態の一因と考えられている。
A decline in the secretion of neurotransmitters is considered one cause of depressive states.
Bunpitsu teika (secretion decline).
グローバル化の進展が、国家主権の実質的な低下をもたらした。
The progress of globalization has brought about a substantial decline in national sovereignty.
Jisshitsuteki na (substantial/actual).
システムの冗長性が失われると、信頼性が著しく低下する。
When system redundancy is lost, reliability declines remarkably.
Technical engineering term 'jouchousei'.
伝統文化の継承者が減少し、技術水準の低下が危惧されている。
The number of successors to traditional culture is decreasing, and a decline in technical standards is feared.
Kigu sarete iru (is feared/viewed with concern).
都市部への人口集中により、地方自治体の機能が低下している。
Due to the concentration of population in urban areas, the functions of local governments are declining.
Chihou jichitai (local government).
情報の過剰供給は、個人の判断力の低下を招く危険性がある。
An oversupply of information carries the risk of leading to a decline in an individual's judgment.
Kajou kyoukyu (oversupply).
Common Collocations
Common Phrases
Often Confused With
Idioms & Expressions
Easily Confused
Sentence Patterns
How to Use It
Sagaru is physical/general; Teika is abstract/formal.
Genshou is for numbers; Teika is for levels.
Always intransitive. Use 'teika saseru' for the transitive 'to lower'.
- Using 'teika' for population decrease.
- Using 'teika' for an elevator going down.
- Saying 'teika suru' for feeling sad.
- Confusing 'teika' (decline) with 'teika' (fixed price).
- Using 'wo' with 'teika suru'.
Tips
Particle Choice
Always use 'ga' for the thing that is declining. 'Nouryoku ga teika suru'.
Kanji Meaning
Remember 'Tei' is low and 'Ka' is down. It's a double downward meaning.
Formal Writing
In essays, replace 'sagaru' with 'teika suru' to sound more academic.
Medical Usage
If a doctor says 'kinou teika', they mean an organ isn't working as well as it should.
Avoid Physicality
Don't use it for elevators or airplanes going down.
Objective vs Subjective
'Teika' is objective. Use it when you have data or a clear standard.
Common Pairs
Learn it as a set with 'kinou' (function) or 'shitsu' (quality).
News Keywords
When you hear 'teika', expect a report on a problem or a negative trend.
The 'T' Sound
Think of 'Temperature' or 'Talent' (Ability) dropping. Both start with T, like Teika.
Politeness
Use 'teika shite imasu' for a polite, professional observation.
Memorize It
Word Origin
Sino-Japanese (Kango) compound used to express a downward movement in abstract scales.
Cultural Context
The 'decline in birthrate' is usually 'shoushika', but the resulting 'labor decline' is 'roudouryoku no teika'.
Japanese companies often use 'teika' in internal reports to avoid the harsher word 'shippai' (failure).
The term 'Yutori Gakuryoku Teika' refers to the perceived drop in student performance during the relaxed education era.
Practice in Real Life
Real-World Contexts
Conversation Starters
"最近、体力が低下したと感じることはありますか？ (Do you feel your physical strength has declined lately?)"
"スマートフォンの使いすぎで、視力が低下しませんか？ (Doesn't using smartphones too much lower your eyesight?)"
"日本の学力低下についてどう思いますか？ (What do you think about the decline in academic ability in Japan?)"
"サービスの質が低下した店に行ったことがありますか？ (Have you ever been to a shop where the service quality declined?)"
"集中力が低下したとき、どうやって回復させますか？ (When your concentration drops, how do you recover it?)"
Journal Prompts
最近、自分の能力で「低下した」と思うものと、その理由を書いてください。 (Write about an ability of yours that has declined recently and the reason.)
社会全体の「質の低下」を感じる場面について述べてください。 (Describe situations where you feel a 'decline in quality' in society.)
どうすれば意欲の低下を防げるか、自分の考えをまとめましょう。 (Summarize your thoughts on how to prevent a decline in motivation.)
健康診断の結果で、機能の低下を指摘されたらどうしますか？ (What would you do if a health check pointed out a decline in function?)
技術の進歩が人間の能力を低下させているという意見についてどう思いますか？ (What is your opinion on the idea that technological progress is lowering human abilities?)
Frequently Asked Questions
10 questionsYes, but 'geraku' is more common for stocks/market prices, and 'sagaru' is more common for grocery prices. 'Teika' is used for the 'value' of money.
Usually, yes. It implies a drop from a standard. However, in medical terms like 'lowering blood pressure', it can be the goal of treatment.
'Teika' is a drop in level (neutral/objective). 'Akka' means it is becoming 'bad' (negative/subjective).
No. Rain falling is 'furu'. Physical falling is never 'teika'.
Yes, it is a Group 3 suru-verb.
Use the causative form 'teika saseru' or a different verb like 'sageru'.
Yes, 'seiseki no teika' is very common.
'Joushou' (rise) or 'Koujou' (improvement).
Less often than 'sagaru'. It's used when talking about health or serious topics.
Yes, 'teika' alone means 'decline' or 'drop'.
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Summary
低下する (teika suru) is the professional choice for describing a decline in abstract levels like quality, health, or ability. Use it instead of 'sagaru' in formal writing to sound more precise and academic.
- Formal verb for 'decline' or 'drop'.
- Used for quality, ability, and function.
- Common in news, medicine, and business.
- Intransitive: [Subject] ga teika suru.
Particle Choice
Always use 'ga' for the thing that is declining. 'Nouryoku ga teika suru'.
Kanji Meaning
Remember 'Tei' is low and 'Ka' is down. It's a double downward meaning.
Formal Writing
In essays, replace 'sagaru' with 'teika suru' to sound more academic.
Medical Usage
If a doctor says 'kinou teika', they mean an organ isn't working as well as it should.
Example
最近、体力が低下したと感じる。
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This Word in Other Languages
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しばらく
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異変がある
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異常な
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擦り傷
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吸収する
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禁酒
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痛む
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鍼灸
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急性的
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