Final answer:
Cortisol is a hormone that may increase or remain constant as a person ages, according to changes in the adrenal glands and overall endocrine system function.
Step-by-step explanation:
During the ageing process, the hormone that may increase as a person ages is cortisol. The adrenal glands, which produce cortisol, change with ageing. While there is an increase in fibrous tissue which may suggest a decrease, the production and secretion of cortisol actually may become slightly higher or not change significantly, unlike other hormones which typically decrease. The parathyroid hormones also tend to increase with age, leading to potential issues like osteoporosis.