what is cortisol?
cortisol is a hormone produced by the adrenal glands, two small glands that sit above the kidneys. it's often labelled "the stress hormone", but that's only part of the story. cortisol has a wide range of everyday functions that go well beyond the stress response.
what does cortisol do?
cortisol is involved in:
- regulating the body's response to stress, both physical and emotional
- helping control blood sugar levels alongside insulin
- influencing metabolism of fats, proteins and carbohydrates
- supporting the sleep and wake cycle, generally being higher in the morning and lower at night
- helping regulate inflammation in the body
the daily cortisol rhythm
cortisol naturally follows a daily rhythm, typically rising in the early morning to help with waking and alertness, then gradually declining across the day to its lowest point around bedtime. this pattern is closely tied to the body's internal clock and is influenced by light exposure, sleep timing and daily routine.
cortisol and other hormones
cortisol doesn't work in isolation. it interacts with reproductive hormones such as oestrogen and progesterone, and with hormones involved in blood sugar regulation and thyroid function. sustained periods of high stress and elevated cortisol are thought to be able to influence the broader hormonal environment, including aspects of the menstrual cycle, though the relationship is complex and varies from person to person.
what influences cortisol levels?
cortisol responds to a wide range of triggers, including:
- physical or emotional stress
- sleep quality and quantity
- illness, injury or intense exercise
- time of day, due to its natural daily rhythm
- certain medications, including some corticosteroids
when cortisol patterns change
persistently high or low cortisol, or a disrupted daily rhythm, can be linked to a range of symptoms including fatigue, changes in sleep, altered appetite and mood changes. certain medical conditions directly affecting the adrenal glands or pituitary gland can also cause cortisol levels to fall outside the usual pattern, and these require specific medical evaluation.
if you're concerned about symptoms that might be related to cortisol or ongoing stress, please speak with a doctor or another qualified healthcare professional, who can assess your symptoms properly and arrange testing if needed.