With summer in full swing and temperatures soaring, it’s essential that kids are staying hydrated. The planet has recorded a series of record-high overall temperatures as heatwaves rage in China and the southwestern U.S.

Dehydration can be more serious than simply feeling thirsty. Being severely dehydrated or dehydrated for long periods of time may lead to heatstroke, urinary tract infections, kidney problems, seizures and hypovolemic shock (from low blood volume).

Even if you’re enjoying more moderate temperatures locally, the long days of summer vacation mean that kids are spending more time outdoors being physically active, which means continually assuring that they’re staying hydrated.

While many of us have memories of keeping ourselves hydrated in summer on a haphazard schedule of otter pops and sips from the garden hose, it’s unusual for us to send our own kids out of the house without a water bottle.

There are a few possible explanations for this generational shift. First, climate change means more days at high temperatures. It’s also more widely acknowledged that drinking water is a healthier choice than juice or sodas, from a medical and dental perspective.

“It’s great that kids carry water bottles and is more the norm now,” Dr. Jen Trachtenberg, a New York-based pediatrician, told HuffPost. She also wondered if some of the ubiquity of water bottles comes from children’s progression to using them following bottles and then sippy cups, which brings an element of comfort as well as hydration.

In addition to encouraging water consumption, here’s what parents need to know about dehydration in kids, including a few symptoms that you may not have considered before.

“It is especially important to keep babies and children hydrated because their bodies contain more water, so they are impacted by water loss more quickly,” Jennifer Williams, a hydration scientist for Abbott, told HuffPost.

Kids are also “more sensitive to heat and can lose fluids more quickly from their smaller bodies,” Dr. Tanya Altman, a pediatrician in California, told HuffPost.

Trachtenberg noted that babies rely on a different cooling mechanism than adults, and “young children also have a higher metabolic rate than adults [and] are therefore more at risk.”

Coupled with babies’ and kids’ limited ability to communicate and identify different physical sensations, this risk means that parents need to maintain awareness of how much water their kids are drinking and if they are beginning to show signs of dehydration. Of course, if a child is having severe symptoms, you will want to get medical attention quickly for them.

Of course thirst is a symptom, as is darker urine. “A well-hydrated person will have clear to pale-yellow urine, often described as ‘straw-colored.’ Medium-yellow urine indicates a need for more fluids, and amber-colored urine is a distinct sign of dehydration,” Williams said.

With an infant, you also want to be on the lookout for:

• fever
• unusual tiredness or lethargy
• fussiness
• dry mouth
• no tears when crying
• no wet diaper for three hours or more

In children, less obvious signs may include:

• dizziness
• headache
• tiredness
• dry mouth
• crankiness
• urinating much less frequently than usual
• constipation
• vomiting

Parents should be particularly attentive to these symptoms in hot weather, when your child is doing a lot of physical activity, or when they have GI illness with vomiting and are having trouble keeping liquids down or experiencing a lot of diarrhea.

Williams also suggested that parents can “pre-game” events such as sports or a beach day by making sure to drink plenty of water beforehand.

Dehydration involves a lack of water as well as electrolytes, which are minerals. “You get your electrolytes throughout the day from what you eat and drink, but when you are losing an excessive amount of fluid, replenishing key electrolytes, such as sodium, potassium and chloride, can go a long way in avoiding negative signs of dehydration like fatigue, dizziness or headaches,” Williams said.

Water is usually all that is needed to restore hydration, but in more serious cases an electrolyte drink may help relieve symptoms. These are widely available in the form of liquids, a powder to mix with water, and even the form of a popsicle.

While we generally think of sodium as something we want to limit in our diets, we all do need some sodium in order to remain hydrated.

One thing to avoid would be caffeine, “as it’s a diuretic and makes you urinate,” Trachtenberg said.

The foods that we eat can also help keep us hydrated. “Water is contained in many foods including fruit and veggies, which have so many health benefits. So making sure your kids eat plenty of fresh fruit and veggies will help keep them hydrated,” Altman said. Tomatoes, kiwis, cucumbers and that summer kid-favorite, watermelon, are all good sources of water.