The adrenal glands are two small organs that sit on top of your kidneys and produce hormones that help your body respond to stress and danger. When something frightening happens, like nearly falling off your bike or hearing a sudden loud noise, your adrenal glands release a hormone called adrenaline that makes your heart beat faster, your breathing quicken, and your muscles tense up, preparing you to react quickly. This is sometimes called the “fight or flight” response.

Your adrenal glands also produce other hormones that help regulate your blood pressure, control inflammation when you're sick or injured, and manage how your body uses energy throughout the day. They're constantly working in the background, adjusting their hormone production based on what your body needs.

When doctors talk about adrenal function, they're discussing how well these glands are doing their job of keeping your body balanced and ready to handle whatever comes your way. Athletes sometimes talk about getting an adrenaline rush during competition, that surge of energy and focus that comes from these remarkable little glands.