Welcome to Paging Dr. Gupta. This is the place I get to tackle your health questions and you've been sending quite a few my way. Jennifer, one of our producers, is joining us today. Welcome Jen. Who do we have first?

Hey Sanjay, today's question is from a listener who's been wondering about going back to school, which feels especially relevant to me too since my daughter's about to start daycare. Have a listen.

Hi, my name is Gina and I'm calling from Southern California. I'm a teacher, I've been teaching for around 25 years. And I was just wondering, do teachers tend to build up an immunity over the years, or does it just depend on the germs going around that season? Besides the flu shot, is there anything else that teachers can do to boost their immune system as they're going back to school? Thanks a lot, love the show.

Gina, thanks a lot for this question. You know, I think a lot of people are thinking about their immune systems, maybe even more so as we head into fall, head into school season. So I've been thinking about this as well, and I'm gonna tell you what you need to know right after the break.

Let's be honest, I know this first hand. Once kids start getting sick, it starts spreading quickly through homes, through neighborhoods, through entire cities. And if you spend a lot of time around your kids, you already know this.

It makes sense that teachers, parents, and caregivers would get sick more often than the average person.

That's Dr. Stephanie James, who teaches immunology and infectious diseases at Regis University in Denver. She points out that there are few factors at play here.

I like to think of the classroom as a giant Petri dish. It's a great place for pathogens to circulate. There are a lot of shared surfaces, and in young children in particular, hand hygiene and good hand washing skills may not be as good and high quality as with older kids and adults. Plus, there are just many pathogens out there. For example, there's over 200 different types of viruses that cause just the common cold. So, if we combine the number of pathogens... And then you put 20 or so people in a classroom for several hours, plus their level of good hygiene practice, there's a good chance that a pathogen can easily spread around and make many people sick.

But I can tell you, it is more than just hygiene. Kids' immune systems are still learning. They haven't been on the planet as long, so they haven't exposed to as many pathogens. They're still trying to figure out what is a threat in terms of pathogens and how to respond. So, colds and common infections in some ways are part of that immune system training. And those exposures happen daily, even from playing in the dirt. For example, one gram of soil, just one gram, has about a billion microbes. So, that gets us back to Gina's question. Do teachers develop some sort of immunity to illnesses over time?

Somewhat. If they were both healthy and able to develop an immune response to pathogens. I think it would make sense and it is logical that school teachers would build up immunity over the years. I have not seen any hard evidence supporting this, but they have been exposed to more pathogens than say an individual working by themselves in an office.

'I think that makes sense. You're just exposed more. You're likely to have more immunity. I think you can say the same thing about healthcare workers. Now, when a teacher gets sick, it depends on two things primarily. Have they been exposed to that specific pathogen before? And does their immune system remember it and respond quickly? Makes sense. If you haven't been exposed a pathogen, you're more likely to get sick. Your immune system has no knowledge of this pathogen. People catch colds yearly, why? Because the virus strain does keep changing, keeps drifting, as they say. Now, there's not a specific way to boost your immune system, but there are ways you can support it and optimize it, if you will. Getting plenty of sleep, that makes a big difference. Eating a balanced diet, specifically high in fruits and vegetables. Exercising, that actually helps build up certain things in your body that can help fight infections. Not smoking, obviously. Stay up to date with your vaccines, manage stress, and take care of your mental health as well. Mental health actually influences how your body makes certain infection-fighting molecules. So if your mental is optimized, that can help you fight infections. Maybe that's not intuitive for a lot of people, but it actually does work.

'So to get your immune system in tip-top shape, focus on maintaining that healthy lifestyle. And I can't stress this enough, you are the best judge of your own body and your own immune system. Listen to your body. Nothing can replace resting and getting enough sleep. Your body has the ability to fight off many things. In fact, even in the time that you've been listening to this, your body has probably fought off some pathogens, but you got to give it the opportunity to do so. So Gina, thank you for that great question. And after the break. We're going to talk about one of those healthy lifestyle changes that we've been getting a lot of questions about: Sleep for you and the whole family.

Alright, we're back with Paging Dr. Gupta. Jennifer, what do we have next?

So this topic actually came up a lot in our inbox and also among our team. We have questions about sleep. How much do we really need? What can we do to sleep better? And maybe most importantly, how we can get more of it.

Look, I just want to be honest and candid with you. There was a time in my life when I did not prioritize sleep. I used to mainly see it as a large chunk of my life spent doing something that wasn't that productive. But I know better now. Getting better sleep. Quality of sleep. Quantity of sleep... It is something that I take very seriously. I measure it. I quantify it. I track it. And I'll tell you what, I am better for it.

'We know sleep is so important. It's your body's way of hitting the reset button. It repairs and strengthens your heart and your immune systems, regulates your metabolism. It's also really crucial for the brain. It is a time when your brain is actually actively clearing out waste products and also taking short-term memories and storing them in the long-term memory areas. But at the same time I'm saying all this, over half of Americans say they're not getting enough sleep. In 2020, the CDC found 1 in 3 adults regularly get less than 7 hours. And chances are you or someone you know probably struggles with this, either to fall asleep or to stay asleep. No surprise, then, many people are looking for ways to sleep better.

So let's talk about what you need to know about a good night's rest. The vast majority of adults need around seven to nine hours. You might hear that and think, I don't need that much. But really, unless you're in a very small minority, less is not enough. When you don't get enough sleep, you're actually at increased risk for physical problems and mental health problems. Heart disease, kidney disease, high blood pressure, diabetes, obesity, depression. You're also probably less productive. You'll have decreased attention span, slower reaction time. And for children, sleep is even more crucial, especially as we're back to school. Children's bodies are growing and a lot of that growth, that happens at night. Sleep plays a major role in that process. And while it can often be hard for kids to adjust to going to bed earlier after a long summer break, it is important that they get the right amount of sleep. And now is the time to really set that schedule in stone. Daily recommended hours of sleep depends on age. For newborns, it's up to 17 hours. They're sleeping almost all the time. For toddlers, 11 to 14 hours a day, including naps. Teenagers, they still need a good chunk of sleep, eight to 10 hours.

Now, it is clear how much sleep we get matters no matter what age we are, so let me give you a few tried and true sleep tips. Start with your sleep environment. Keep it dark and cool, okay? And cool is surprisingly important. We talked to another expert, Dr. Rebecca Robbins, about this. She is a sleep scientist at Brigham and Women's Hospital and a professor of medicine at Harvard Medical School.

Temperature really matters. A warm bedroom above 70 degrees has the risk of increasing your risk for nightmares. So individuals in warmer environments actually have more disruptive dreams or nightmares and just general sleep fragmentation. Whereas a cooler temperature is better able to support our good sleep, pull us into deeper stages sooner and help us stay there.

Wow, I didn't actually know that. The thing about nightmares. So keep it cool. Set a consistent sleep routine that cues your body and brain. I like to wind down about 30 minutes before bed. I keep the lights low, the room cool, and I unwind. Some people like white noise, me not so much, but for some people that white noise can help drown out other noises and use blackout curtains if you have to. Now, as a parent, I know that not all kids do well in complete darkness. So we checked in with the pediatrician, Dr. David Hill. You may remember him from our recent episode on parenting recommendations. We wanted to get his thoughts on whether or not your room really has to be pitch black for your little one.

'If your child wants to use a night light that's great - but keep it dim and try and find one that is on the red or orange spectrum instead of white or blue because we know that white or blue light can keep them awake longer even if it makes them feel more secure.

'And that same advice goes for adults. Be aware of devices. Research has found that the body will slow or stop its natural production of the hormone melatonin if exposed to light. Melatonin, by the way, the hormone of darkness - that is something that is actually excreted at night. So try to eliminate any light, even the blue light, from your charging smartphone or your laptop. Go to bed at a reasonable time, one that actually allows you to get enough shut-eye, that's just basic math, and keep a regular schedule. Go to bed, wake up same time every day, that consistency will really reinforce your sleep-wake cycle.

And again, for kids, shifting back into that school routine can be difficult after summer, and sleep is probably one of the first things to get thrown off. The American Academy of Pediatrics estimates that sleep problems affect 25 to 50 percent of children. Dr. Hill says try to get them to wake up at the same time as well on the weekends that they do on school days. That's a tough one, but it can be important. If you get it right, you'll find that Monday and Tuesdays are going to be much better days for them.

'Exercise helps as well, but don't do it within two to three hours of bedtime. That can be too activating. Diet-wise, avoid alcohol, spicy food, caffeine, ideally at least six hours before bedtime. Heavy meals can also affect sleep and not in a good way. And as far as melatonin, again, this hormone of darkness, I'll tell you what, I looked into this and the evidence is mixed. Studies show that it can help with things like jet lag, but not really recommended for chronic insomnia. And there are some safety concerns for older people. The 2015 guidelines from the American Academy of Sleep Medicine recommends against melatonin in people with dementia. Short term use of melatonin -- I think that's fine -- it appears to be safe for most people, but the thing is we just don't know as much about long-term use. As always, talk to your doctor about this.

And look, if your best attempts to fall asleep are falling short, you're still finding yourself just tossing and turning... If you can't fall asleep after 20 minutes, get out of bed. Maybe go to another room. Make sure the lights are dim in that room. Read quietly, listen to some quiet music, try some relaxation techniques. Do this sitting up rather than laying down. Do not watch television. Do not look at your phone. Wait till you feel sleepy, not just tired. Then try going back to bed.

I know that this is a stressful topic. Sleep can be a stressful topic, falling asleep, staying asleep, getting enough sleep. It's not always easy, but it is important. We spend about a third of our lives sleeping and many times we don't get it right. We focus so much on how we move and how we nourish ourselves. We got to think more about how we rest for the current you and the future you.

So tonight give yourself the chance to get some quality sleep. I promise you, your body and brain will thank you.

'That's a wrap for today. Just wanna say these questions really matter. I listen to them, I pay attention. They help people in their everyday lives. They spark real conversations, even among our team. And honestly, I'm learning as well right alongside you. I wanna thank our guests and our experts today. Keep those questions coming. I'm gonna be on this journey with you. You've got something that you've been curious about, send it our way. We might answer it on our next show. Record a voice memo, email it to asksonj.cnn.com, or give us a call 470-396-0832 and leave a message.