疲労

The Japanese word 疲労 (ひろう - hirou) is a noun that translates most accurately to 'fatigue' or 'exhaustion.' While English speakers might use the word 'tired' for everything from a late night to a medical condition, Japanese distinguishes between the common, everyday feeling of being tired—疲れ (tsukare)—and the more formal, physiological, or cumulative state of 疲労 (hirou). Understanding this word requires looking at its kanji: 疲 (tiredness/fatigue) and 労 (labor/exertion). Together, they imply a state of being worn out by physical or mental labor. This is the word you will see in medical reports, sports science journals, and news broadcasts discussing the health of the nation.

Formal Contexts

Used by doctors and health professionals to describe a patient's condition, such as 'chronic fatigue syndrome' (慢性疲労症候群).

Physical Science

Used in engineering to describe 'metal fatigue' (金属疲労), showing the word's breadth beyond just biology.

In Japanese society, the concept of fatigue is deeply tied to the work ethic. The term hirou often appears in discussions about the 'salaryman' lifestyle. Because Japanese culture values hard work, admitting to tsukare (feeling tired) can sometimes sound like a complaint, whereas discussing hirou (physiological fatigue) sounds more like a factual report of one's physical state. This nuance is crucial for B1 learners who are moving from basic survival Japanese to professional or social integration. When you see hirou on a bottle of energy drink (nutritional supplements), it is there to sound scientific and effective. It promises to combat the physiological 'state' of fatigue, not just the 'feeling' of being tired. Furthermore, the word appears in compounds like hirou-kaifuku (recovery from fatigue), which is a common marketing term for spas, supplements, and even certain foods. By using hirou, the speaker elevates the conversation from a subjective mood to an objective physical reality that requires attention and care.

Objective Measurement

In Japanese news reports, you might hear 'hirou-do' (degree of fatigue), treating it as a measurable metric.

Finally, it is worth noting the visual components of the word. The radical 疒 (yamai-dare) in the first kanji 疲 signifies sickness or illness. This reinforces the idea that hirou is not just a passing feeling but a condition that affects the body's health. When you use this word, you are acknowledging that the body or mind has reached a limit that requires rest. It is a more serious, heavy word than its common counterparts, making it essential for discussing health, work-life balance, and long-term well-being in a Japanese context.

Using 疲労 (hirou) correctly involves understanding its role as a noun and its occasional use as a 'suru' verb. However, its noun form is far more prevalent in daily written and formal spoken Japanese. It usually acts as the subject or object in a sentence, or as part of a compound noun. Because it is a Sino-Japanese word (kango), it carries a weight of authority and precision. In English, we might say 'I'm exhausted,' but in Japanese, we often speak about 'fatigue' as something that 'accumulates' (tamaru) or something one 'feels' (kanjiru).

Accumulation

The most common verb paired with hirou is 'tamaru' (to accumulate). Example: 疲労がたまっている (Fatigue is building up).

Another frequent usage is in the phrase hirou-konpai (疲労困憊), a four-character idiom (yojijukugo) that means being utterly exhausted or 'dead tired.' This is used when someone is so tired they can barely move. While hirou alone is formal, hirou-konpai is often used in literature or dramatic storytelling to emphasize the extreme state of the character. When you want to describe the cause of fatigue, you use the particle ni yoru (due to). For example, 'overwork-induced fatigue' is ka-rou ni yoru hirou. This structure is very common in news reports and medical documentation.

In a work context, you might encounter hirou-do (degree of fatigue). Companies often conduct 'stress checks' and 'fatigue checks' to ensure employees are not overworking. You might see a survey asking: 'あなたの疲労度はどのくらいですか？' (What is your degree of fatigue?). In this case, hirou is treated as a quantifiable state. Furthermore, the word is used to describe different types of fatigue. Nikutaiteki-hirou (physical fatigue) is contrasted with seishinteki-hirou (mental fatigue). If you are studying for exams, you are likely experiencing the latter. If you just ran a marathon, it's the former.

Recovery Phrases

Phrases like 'hirou-kaifuku' (fatigue recovery) are essential for navigating health products in Japan. You will see this on bath salts, vitamins, and energy drinks.

When describing someone else, hirou sounds more empathetic and observational than tsukare. Saying 'Kanojo wa hirou shite iru you da' (She seems to be suffering from fatigue) sounds like you are concerned about her health, whereas 'Kanojo wa tsukarete iru' simply means she looks tired right now. The use of hirou suggests a deeper, perhaps more chronic issue. This distinction is vital for nuanced communication in professional Japanese environments where health and stamina are frequently discussed topics.

You will encounter 疲労 (hirou) in several specific domains in Japan. First and foremost is the medical and health industry. If you visit a Japanese clinic complaining of persistent tiredness, the doctor will not just say you are 'tsukarete iru.' They will use terms like zanshin-hirou-kan (a feeling of general fatigue) or mansei-hirou (chronic fatigue). On medical forms, you will often see a checkbox for hirou-kan (sense of fatigue). This is because hirou is the standard clinical term for the state of being worn out.

In the News

News anchors use 'hirou' when reporting on national health trends, the effects of heatwaves (natsu-bate), or the mental toll of long-term social issues.

The world of sports is another place where hirou is ubiquitous. Sports commentators use it to explain why a player missed a shot or why a team is performing poorly late in the season. They might talk about kin-hirou (muscle fatigue) or chikuseki-hirou (accumulated fatigue). In this context, it isn't a sign of weakness but a physical factor that athletes and coaches must manage. Training schedules are often designed around hirou-nuki (getting rid of fatigue/recovery days). If you watch sports news like 'Housou Sports' or read 'Sports Nippon,' you will see this word constantly during the Olympics or major tournaments.

In the corporate world, hirou is a key term in Human Resources. With the rise of 'Work-Style Reform' (Hatarakikata Kaikaku) in Japan, companies are more focused on preventing karou (overwork). You will hear managers talking about the hirou-chikuseki (accumulation of fatigue) in their teams. It is also used in safety training for jobs involving heavy machinery or driving. For instance, truck drivers are required to take breaks to prevent unten-hirou (driving fatigue). In these environments, using the formal hirou instead of tsukare signals that the fatigue is a serious risk factor that needs to be managed according to regulations.

Engineering and Materials

In technical documentaries or reports about infrastructure, you may hear about 'kinzoku-hirou' (metal fatigue) causing cracks in bridges or airplane parts.

Lastly, in literature and high-end journalism, the word is used metaphorically. You might read about shakai-teki-hirou (social fatigue) or seiji-teki-hirou (political fatigue), describing a populace that is weary of certain news or systems. This usage shows that hirou is a versatile tool for describing any system—biological, mechanical, or social—that has been pushed to its limit and is losing its resilience.

The most frequent mistake English speakers make with 疲労 (hirou) is using it in casual, daily conversation where 疲れ (tsukare) or the verb 疲れる (tsukareru) would be much more natural. For example, if you finish a workout and say to a friend, 'Hirou shita!' it sounds incredibly stiff and robotic—almost like saying 'I have achieved a state of physiological fatigue!' in English. Instead, you should simply say 'Tsukareta!' (I'm tired!).

Confusing Noun and Verb

Unlike 'tired' which is an adjective, 'hirou' is primarily a noun. You cannot say 'Watashi wa hirou desu.' You must say 'Hirou wo kanjite imasu' (I am feeling fatigue) or 'Hirou ga tamatte imasu' (Fatigue is accumulated).

Another mistake involves the nuance of the word hirou versus kentaikan (malaise/languor). While hirou is fatigue from effort or labor, kentaikan is a more general feeling of being unwell or 'blah' often associated with illness like the flu. Learners often swap these when talking to doctors. If your tiredness is because you worked 14 hours, use hirou. If your tiredness is because you have a fever and no energy, kentaikan is the more precise medical term.

There is also the issue of 'over-formalizing' your speech to sound polite. Some learners think that because hirou is more 'advanced' than tsukare, using it will make them sound more fluent. In reality, it can make you sound like you're reading from a textbook. In Japanese, 'naturalness' often comes from choosing the simplest word that fits the context. Unless you are in a meeting discussing health and safety, or at a doctor's office, stick to tsukare.

Kanji Miswriting

Learners often confuse '疲' (tired) with '病' (illness). While they share the same radical, the inside part is different. Make sure to practice the 'pi' (皮) inside 疲.

Finally, be careful with the phrase hirou-enban (fatigue disk), which doesn't exist. Some learners try to translate 'exhaustion' literally and end up with strange compounds. Stick to established collocations like hirou-chikuseki (accumulation of fatigue) or hirou-kaifuku (recovery). When in doubt, use the 'noun + ga + tamaru' (fatigue accumulates) or 'noun + wo + kanjiru' (feel fatigue) patterns, as these are the most standard and safest for a B1 learner to use.

To truly master 疲労 (hirou), you must see how it fits into the ecosystem of 'tired' words in Japanese. Depending on the cause of the tiredness and the level of formality, the word you choose will change significantly. Here is a breakdown of the most common alternatives and how they differ from hirou.

疲れ (Tsukare)

The most common, everyday word. It is subjective and emotional. 'Hirou' is the physical state; 'Tsukare' is the feeling.

疲弊 (Hihei)

A much stronger word meaning 'exhaustion' or 'impoverishment.' It is often used for economies or organizations that are worn out. 'Economic exhaustion' is 'Keizai-teki hihei.'

Then there is 倦怠感 (Kentaikan), which we mentioned earlier. This is specifically the 'weariness' or 'lethargy' associated with illness. If you have a cold, you feel kentaikan. If you worked out, you feel hirou. Another interesting word is 消耗 (Shoumo), which means 'depletion' or 'wearing out.' It's often used when talking about energy or resources. 'Tairyoku wo shoumo suru' means to exhaust one's physical strength.

In very formal or literary settings, you might see 困憊 (Konpai). This is almost never used alone; it's usually part of hirou-konpai. It implies a state of being so exhausted that you are at your wits' end or physically unable to continue. For mental tiredness specifically, shinrou (心労) is used. This refers to 'worry' or 'mental strain' caused by difficult personal circumstances or heavy responsibilities. If you are tired because you are worried about your parents' health, that is shinrou, not just hirou.

くたくた (Kuta-kuta)

An onomatopoeic (gitaigo) expression for being 'worn out' or 'dog-tired.' This is very common in casual speech: 'Mou kuta-kuta da!'

By understanding these distinctions, you can choose the right 'flavor' of tiredness. Hirou remains the 'standard' formal noun for the physical state, making it the bedrock of health-related vocabulary. As you move toward C1/C2, you will start to use hihei and shoumo to describe more complex systems, but for B1, mastering the hirou vs. tsukare divide is your primary goal.