People start to age from the moment they are born. Their body functions gradually decline and they become affected by diseases and disabilities. But most of them only become aware of it when they reach their 40s.
Not everyone age the same way. Even different parts of the body may age at different rates.
In the older person, disease and their complications are presented differently from the younger adult. It affects their functioning and independence and the need for long-term care. Recovery is also slower and may be incomplete.
But there are some changes that, in varying degrees that affect everyone.