A cup of water first thing in the morning, and staying hydrated could be a secret weapon to help young minds with learning. Photo: RNZ
If you're a student of Karen Tui Boyes, an education author and online teacher, your phone is likely loaded with an hourly alarm throughout the day reminding you to drink water.
If a student doesn't have a phone, Boyes suggests carrying a drink bottle as a physical cue to hydrate.
"The things you see in the classroom when students are dehydrated are that they have more difficulty following instructions, critical thinking is harder, creativity is harder, and learning new information is more challenging," she says.
"The body has to decide what it's going to spend its energy on and if you are dehydrated, the body will spend its energy on trying to hydrate rather than trying to learn."
In an age when everyone - including kids - seems attached to a drink bottle, it might be strange to ponder whether hydration can impact learning at school. However, research shows that hydration is a factor in learning abilities, mood and behaviour in the classroom.
Karen Tui Boyes. Photo: Supplied
Despite that seemingly ever-present water bottle, many kids start the day with low hydration reserves that deplete further throughout the day. But it isn't just drinking fluid that's important: what you drink and what you eat can majorly impact your hydration, and your learning.
What does the research say about hydration and learning?
The impact of hydration is difficult to research and there is still a lot we don't know about how it is intertwined with learning, says Jim Cotter, a physical education professor at the University of Otago.
"There's some indication that hydration can affect [students'] cognition, so the processes they use to learn. But how much it actually affects their learning, we're not sure," he says.
Cotter pointed to some studies that showed an immediate improvement in mental function in the hour after students drank about a cup of water. Although, if a student turned to a sugar drink instead of water then "they would be better off without it."
Professor Jim Cotter. Photo: Supplied
One thing we know from research is that kids are turning up to school under-hydrated.
"They're not starting off the day in the best possible way, so it is important to have access to water at school and it would be even better if they had more of it when they got up in the morning," says Stephen Hill, an associate professor of cognitive psychology from Massey University.
Boyes, the online educator, encourages her students to drink at least one glass of water when they wake up. That is often when our hydration levels are at their lowest.
"There is pretty good evidence that well-hydrated kids tend to seem to be more on task than not low-hydrated kids," says Hill. "It's something that can potentially improve in the classroom if we pay attention to it."
Hydration can fuel young brains towards better memory, attention span and cognitive flexibility, which is the ability to switch thinking between two concepts, according to The Conversation.
On the flip side, cortisol levels begin to increase even when children (and adults) have even mild levels of dehydration, potentially making us more nervous, tense and irritable.
But too much water can also distract, including the need for frequent bathroom breaks, so a balance needs to be struck, Cotter says.
How much water should children have?
The Institute of Medicine in the US recommends the following, per day:
- 1 to 3-year-olds: 900 milliliters
- 4 to 8-year-olds: 1.2 litres
- 9 to 13-year-old males: 1.8 litres
- 9 to 14-year-old females: 1.6 litres
- 14 to 18-year-old males: 2.6 litres
- 14 to 18-year-old females: 1.8 litres
- Adult males: 3 litres
- Adult females: 2.2 litres
However, our total daily water intake is more than these recommendations because 30 to 50 percent of what we need to stay hydrated comes from food, according to Hill and Cotter.
Wait. What? Food can keep me hydrated?
Yes, but not just any food. Our body pulls a lot of water from whole foods such as fruit and vegetables. Processed and ultra-processed foods not so much.
It's one of the reasons why Boyes believes dehydration is a modern problem despite our attachment to drinking bottles.
"You think about our grandparents' and great-grandparents' generation - they ate a lot of fruit and vegetables so they didn't even get dehydrated."
Another of Boyes' hydration recommendations to her students is to have a whole-food breakfast that includes fruit, a protein like eggs or unsweetened yogurt and a carbohydrate such as oats. (Check out our guide to an ultra-processed breakfast vs a whole-food breakfast).
What can dehydrate you?
It's well known that caffeine and alcohol are diuretics, meaning they make you wee more often, depleting your water stores faster.
Boyes recommends that her students - and adults - drink three cups of water for every cup of coffee they consume.
Processed or ultra-processed foods - like chips, store-bought bread and crackers - are low in water content and likely high in salt. The body needs more water to eliminate the extra salt, so a diet low in whole foods will require more water to digest.
Do kids need to be reminded to drink water at home and school?
For different reasons, children and the elderly seem to have blunted messaging from their bodies when it comes to hydration, says Cotter.
In the classroom, kids typically start school with good drinking habits instilled by early learning centres, according to Kahli Oliveira, the deputy principal at Auckland's Konini Primary School.
Yet "on hot days ... even adults need reminding of how much water they need to be drinking," she says.
Young children also need a reminder to take off warm clothes, especially when they get caught up in the excitement of play.
"If you get really hot, take your shoes and socks off so your feet can breathe and then you can cool your body down."
Neurodiverse children often have more trouble regulating their body temperature. When they get over-stimulated, Konini Primary School teachers enact their secret weapon: an ice-cold cup of water from the staffroom's water cooler.
"... honestly, it works miracles," Oliveira says.
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
