Do dehydrated kids perform worse at school?

By Bob Fear

Do dehydrated kids perform worse at school?

It's been suggested that children who are mildly dehydrated at school have a low concentration span, impaired fine motor skills and poorer short-term memory. 

Various bits of research have been done to find out if children who are properly hydrated perform better and are better behaved in school.

What does the science tell us

  • Children who had extra water performed visual attention tasks better than those who hadn't had any extra water1
  • Children who were given water to drink at school had significantly improved skills such as handwriting and ability to copy text2
  • The number of items that children could repeat in sequence was significantly reduced if they became dehydrated3
  • Drinking extra water over the course of the school day helped to improve children's short-term memory3 

How much water should a child be drinking

Even though a child's body is made up of 60% water, just a 1% to 2% loss of water means they're dehydrated.

The latest recommendations for what kids should be drinking to stay hydrated (ideally water or milk) depends on their age and gender:

Boys & Girls Aged 2 - 3 0.9 - 1 litres
Boys & Girls Aged 4 - 8 1.1 - 1.3 litres
Girls Aged 9 - 13 1.3 - 1.5 litres
Boys Aged 9 - 13 1.5 - 1.7 litres
Girls Aged 14 - 18 1.4 - 1.6 litres
Boys Aged 14 - 18 1.8 - 2 litres

Soft drinks are not a good alternative

Soft drinks, fruit juices and smoothies contain too much added sugar to be considered a good source of hydration. 

The high-levels of sugar can cause tooth decay and obesity, so it's best that children stick to water, low fat milk, or drinks free from added sugar. Not to mention that the caffeine content is not recommended for young children. 

To avoid any potential short and long-term health issues, it's time to get the kids to quit the sugary drinks and get them sipping something good, like crisp filtered water!


1. Edmonds CJ & Burford D (2009) Should children drink more water?: The effects of drinking water on cognition in children. Appetite 52(3), 776-9.
2. Booth P et al. (2012) Water supplementation improves visual attention and fine motor skills in schoolchildren. Education and Health 30(3), 75-79.
3. Fadda R et al. (2012) Effects of drinking supplementary water at school on cognitive performance in children. Appetite 59(3), 730-7.

Want to keep up to date with all things Purist?

Sign up to our newsletter to get the lastest from the Purist delivered to your inbox every month.