Sports, Exercise and Health Science · A.2 Hydration and nutrition

SEA.2.1 — Water and electrolyte balance

Sports, Exercise and Health Science · SL / HL · syllabus-mapped notes

1. SEA.2.1.1

   Water and electrolyte balance

   Water and electrolyte balance is necessary for effective functioning of the body and is influenced by the environment.

2. SEA.2.1.1.1

   Intake and loss

   Water and electrolyte intake occurs via the large intestine. Loss of fluids and electrolytes occurs via evaporation through the skin and the respiratory tract, and excretion via osmosis.

3. SEA.2.1.1.2

   Dehydration, hypernatremia, hyponatremia

   Dehydration, hypernatremia and hyponatremia are three states that can occur if water and electrolyte balance is not maintained. This will affect health and performance.

4. SEA.2.1.1.3

   Measuring hydration status

   Water and electrolyte balance can be measured in a variety of ways, including body weight, urine colour and osmolarity.

5. SEA.2.1.1.4

   Regulating electrolyte balance

   Electrolyte balance is regulated by the hypothalamus, pituitary gland and kidneys. Knowledge of the function of the nephron and the structure of the kidneys are not assessed.

6. SEA.2.1.1.5

   Cardiovascular drift

   Cardiovascular drift is caused by water loss from the body or an increase in core body temperature during a prolonged steady state of submaximal (or aerobic) exercise in thermoneutral and hot environments.