IB Sports, exercise and health science A.3 Response Key Definitions

Acidosis occurs when the pH within muscle fibers decreases, typically due to an accumulation of H⁺ ions, resulting in impaired muscle function and fatigue.

Active recovery is submaximal activity performed after fatiguing exercise, with the aim of accelerating return to homeostasis through faster lactate clearance and improved metabolite removal.

Adenosine triphosphate (ATP) is the primary chemical energy currency of the cell. Hydrolysis of ATP releases the energy used for muscle contraction, ion transport, and most other energy-requiring processes.

Body fat that stores energy and fat-soluble vitamins.

Chest pain caused by reduced blood flow to the heart muscle.

A negative emotional state marked by feelings of nervousness, worry, and apprehension about future events, often without a clear external cause.

Atherosclerosis is the accumulation of fatty deposits (plaque) in the arterial walls, which causes the arteries to become stiff and narrow, reducing blood flow.

White blood cells responsible for producing antibodies that fight off pathogens.

The amount of energy required by the body to maintain basic physiological functions at rest.

A measurement that uses height and weight to assess whether an individual has a healthy body weight.

Bone is a dense, hard connective tissue that forms the skeletal structure of the body, playing an essential role in movement, support, and protection of vital organs.

Bone mineral density (BMD) is the amount of mineral (mainly calcium) per unit area of bone, used as the main measure of bone strength.

Cardiovascular Disease (CVD) refers to a broad range of conditions that affect the heart and blood vessels.

Central fatigue is the decline in neural activation of muscles due to changes in the brain and spinal cord, reducing an individual’s ability to sustain forceful contractions.

An injury that develops gradually over time, usually due to repetitive overuse of a body part. Chronic injuries are also known as overuse injuries.

Chronotype describes an individual's natural predisposition toward morning alertness, evening alertness, or somewhere in between. It is shaped by genetics, environment, and age.

Circadian rhythm is the body's internal 24-hour biological cycle that regulates sleep, wakefulness, body temperature, hormone release, and other functions. It is synchronised to external cues, especially light.

Clinical depression is a mental illness involving long-term depressed mood, loss of interest or pleasure, low self-worth, disturbed sleep or appetite, low energy, and poor concentration, lasting months or years and interfering with daily life.

The mental processes involved in gaining knowledge and understanding, including memory, learning, and problem-solving.

Coronary heart disease (CHD) is a narrowing of the coronary arteries due to atherosclerosis, reducing blood supply to the heart muscle and raising the risk of heart attack.

A hormone produced during stress that, in excess, can suppress immune function and impair immune responses.

A supplement that enhances ATP replenishment, muscle hydration, and recovery from high-intensity exercise.

Cryotherapy is the local or whole-body application of cold for recovery or treatment. It reduces metabolic activity, constricts capillaries, lowers nerve conduction velocity, and limits inflammation.

A cytokine is a protein that acts as a chemical messenger to regulate the immune system.