Hydration (AQA GCSE Physical Education (PE))

Reasons for Maintaining Water Balance

• Dehydration occurs when the body does not take in enough water to supply the needs of the body's metabolism and to resupply the water that is lost via excretion (e.g. sweat)

• Consuming water in food and drinks (hydrating) is essential for preventing dehydration

  • This is particularly important during exercise when increased sweat is lost to the environment

• There are several consequences of prolonged dehydration. These include:

  • The slowing down of blood flow due to 'thicker' blood with high viscosity. This reduces the delivery of essential chemicals like glucose and oxygen to the cells

  • Heart rate increases to try and counteract the effect of the slow-flowing blood

  • Sweating is a very important mechanism for cooling the body down. Without excess water for sweat, the body can easily overheat

  • The reduction in blood flow to the brain and muscles can also increase reaction times and lead to poor decision-making

    • This can have a particular impact on sporting ability and success in competitive environments

  • Muscle fatigue and cramps are also common symptoms of dehydration as muscles suffer from a lack of oxygen due to slow blood flow