(percussive music) (tennis ball thwacking) - [Narrator] For countless student athletes throughout California, playing an outdoor sport means they'll likely have to endure some hot practice days.

With California experiencing more frequent extreme heat events and longer heat waves, those days can be tough on the body and mind.

- It's definitely hard lunging after every ball when you can feel the heat beating down on you.

So, it's also just a mental challenge trying to push through that.

- [Narrator] In addition to impacting an athlete's performance, there's increasing focus on how those hot days impact their health and safety.

National research shows that heat-related illness is among the top three causes of death for high school athletes in the US.

In 2024, the California Interscholastic Federation or CIF, the governing body for high school sports became one of 15 states to pass an Extreme Heat and Air Quality Policy.

It provides a set of standard rules for teams that practice and play on hot days.

- Some people have rules, some people didn't have rules, some people had different rules.

We wanted to standardize those rules with regard to heat illness.

And again, it comes down to the safety of student athletes.

(alarm beeping) - [Narrator] The new policy requires the use of this.

The Wet-Bulb Globe.

It's a tool that's placed on the same surface the athletes will be using.

It measures not just the temperature but humidity, wind speed, sun angle and solar radiation, providing a better assessment of how dangerous the heat is that day.

- It takes the guessing out of, "Is it okay as a coach?

Should we go out and do this?"

You know, where you could be criticized.

It takes the guessing out of players saying, "Well, isn't it too hot out here?"

And so, I think it's a really good system.

- [Narrator] The globe provides a reading which corresponds with outdoor activity guidelines.

Those guidelines clarify how many rest and water breaks that students need, how long they can practice outside, and whether additional gear like shoulder pads and helmets should be restricted.

- Right now, just on the reading from the globe, it would be considered a, "Hey, right now we're in yellow.

You can have your two-hour practice.

Just make sure that you're hydrating, making sure that you're watching and paying attention to what's going on."

- [Narrator] The new policy also helps students acclimate to extreme heat during the first few weeks of the fall sports season.

Finnegan says they start football practice in July when temperatures often reach triple digits.

- It definitely is a shock that first week when you come back and get pads on in the heat, especially our helmets with our school, it's black and it kinda just adds a little bit.

- [Narrator] During the acclimation period, coaches monitor athletes closely and gradually increase activity.

- Ready?

- Break.

- [Narrator] There's also a focus on water breaks.

When they're needed, practice schedules are changed to mornings instead of after school.

- That's good.

There we go.

- [Narrator] Tennis coach and PE director Jill Butler says this is a clear and much needed change in how hot days and high school sports have worked in the past.

- When I was in high school, there were no heat rules.

We practiced no matter what.

Rain or shine, smoke, heat.

It made you tougher back then.

And now, I think we're tougher by being prepared and not putting our bodies in danger.

- [Narrator] For football, that may mean moving to an indoor workout or the weight room during dangerous heat times.

Where a team may once have pushed harder in the heat, coaches say they're now required to be smarter, which takes a lot of pressure off everyone.

- You know, in football you kinda get the mentality of the toughness is gonna make us better.

We have to go through and do it, right?

I think it takes that off the coach.

The coach has the reading and this is what it is, and I think it builds a trust between the coaches and players.

- [Narrator] Coaches and athletic directors say the trust, transparency, and clear guidance makes handling hot days easier for everyone while also providing an important lesson for students.

- We only have these kids for four years and they're gonna continue to play sports and be outdoors, especially in California.

So, we want them to understand if they feel dizzy or they're not sweating anymore, they know how to take care of their bodies.

So, we're teaching life skills and making lifelong learners out of these kids.

So that's, we think it's really important.

- [Narrator] For these student athletes, that life skill means understanding that being tough also means being smart about extreme heat.

(tennis ball thwacking)