Hydration
Physical Education: AQA GCSE, topic 8.3.3
Hydration
Water makes up most of the human body (about 70%) and helps with chemical reactions in the body, such as lubrication (body processes running smoothly) and thermoregulation (maintaining body temperature). Therefore, it’s vital that we stay hydrated. The factors affecting hydration are:
Environment
- Depending on where we are, the amount of water we need can change.
- E.g. in a desert we will need to drink more water to help keep us cool.
Temperature
- The hotter we are, the more we will sweat and the more water we will lose. We need to drink more water to replace the water lost in sweat.
Exercise
- If we exercise, we are more likely to lose water (by sweating), which we will need to replace.
Dehydration
If we do not keep the water balance in our body, we can become dehydrated (lose too much water). Dehydration can lead to:
Thickening of the blood
- This means that water is lost from the blood, so the blood becomes thicker.
- This reduces blood flow.
Increased heart rate
- Thicker blood means the heart has to work harder and beat more to maintain the blood supply to the body.
- This can cause an irregular heartbeat.
Longer reaction time
- This means that it takes longer to respond to a stimulus.
- Increased reaction time can result in a decrease in performance.
Fatigue
- Muscles can cramp and fatigue will happen more quickly because of water loss.
- This is because waste products cannot be removed as quickly as usual.
Increased body temperature
- The body can also begin to overheat as there is less water to cool the body down
Test yourself on Hydration
Which of the following is not a factor affecting hydration?
What % of the human body is water?
What chemical reactions does water help with in the body?
Consequences of dehydration