Physical Changes with Ageing Every Care Worker Should Know

Development & aging（発達と老化の理解）· Material

老化に伴う心身の変化 · Updated 26 October 2026

The 発達と老化の理解 field tests the understanding that ageing （老化） is a natural process distinct from disease. Physical changes appear gradually, vary greatly between individuals, and many functions remain well preserved into old age. A care worker who understands these changes can tell what is normal for age and what is a sign of illness that must be reported.

General features of ageing

Ageing proceeds gradually, and its speed and form differ greatly from person to person （個人差が大きい）. Assessment must therefore not be based on calendar age alone; each older person's condition has to be looked at individually.

The body's reserve capacity （予備力） declines, so older people fall ill more easily under added strain such as infection or environmental change, and recovery tends to take longer. On the other hand, functions such as crystallised memory and vocabulary are relatively well preserved.

• Ageing ≠ disease; the process is gradual
• Individual differences are very large
• Reserve capacity （予備力） declines, recovery slows

Changes in vision and hearing

In the eyes, the lens hardens so near focus declines （老視， presbyopia), the lens can cloud into a cataract （白内障）, and adaptation to light and dark slows. Older people are dazzled more easily and need brighter lighting.

In the ears, age-related hearing loss （老人性難聴） begins with high-pitched sounds, making consonants such as "sa" and "ta" hard to distinguish. When speaking, face the person, talk slowly in a slightly lower voice, and do not shout from a distance.

• 老視： difficulty focusing at close range; 白内障： clouded lens
• 老人性難聴： high pitches are affected first
• Communication: face the person, speak clearly and slowly

Bones, muscles, and joints

Bone mass decreases （骨粗鬆症， osteoporosis), especially in women after menopause, so fractures can occur from even a minor fall. Typical sites are the neck of the femur （大腿骨頸部骨折） and the spine （脊椎圧迫骨折）.

Muscle mass and strength also decrease （サルコペニア）, walking speed slows, and the back tends to round （円背）. The combination of fragile bones and weak muscles is what makes falls in older people so serious.

• 骨粗鬆症： fragile bones, high fracture risk
• サルコペニア： loss of muscle mass and strength
• Typical fractures: femoral neck and spine

Regulation of temperature and body fluids

Total body water decreases with age and the sense of thirst becomes dull, so older people easily become dehydrated （脱水） without noticing. Early signs include dry mouth and skin, reduced urine, and mild confusion; fluids should be offered regularly rather than waiting to be asked.

Temperature regulation also weakens: sweat glands respond more slowly, so heat is hard to release and the risk of heatstroke （熱中症） rises, while cold is also noticed late. Care workers need to monitor room temperature and clothing.

• Dull sense of thirst → high 脱水 risk
• Weaker temperature regulation → 熱中症 risk
• Offer drinks regularly; do not wait to be asked

Key terms

Frequently tested points

• 老人性難聴 begins with high pitches, not low ones.
• Dehydration in older people often occurs without thirst — do not wait for the person to ask for a drink.
• Ageing shows 個人差が大きい： never judge a person's condition from age alone.
• Typical fractures in older people: 大腿骨頸部骨折 and spinal compression fractures.

Independent study material for the Japanese national Certified Care Worker exam (介護福祉士国家試験). Official terms and rules may change — always cross-check with the latest official sources.