Caitlin Whyte (Host): Welcome to Flourish. I'm your host, Cailtin Whyte. Joining me is Dr. Kelly Spence, an Internal Medicine and Pediatrics physician from Prisma Health. In this episode, we delve into the hidden risks of caffeine in adolescents, examining how caffeine affects children and teens and why they are particularly susceptible.

Well, Doctor, let's start off our episode here with some basics. Why are teens particularly vulnerable to the effects of caffeine?

Dr. Kelly Spence: Yes. And so, I think we need to make sure we're operating under the same understanding of what caffeine is for the rest of the podcast. We know caffeine use is highly prevalent among adolescents. Most folks are consuming at least one caffeinated product daily, usually from sources like coffee, tea, chocolate, sodas and, increasingly, energy drinks. But caffeine is a natural stimulant that acts on the brain and the central nervous system. And the way it works is by blocking adenosine receptors in the brain. Adenosine is the neurotransmitter that's responsible for sleep and relaxation. So by blocking it, that's how we get the increased alertness and wakefulness associated with caffeine. It can also stimulate the release of other neurotransmitters, like dopamine or norepinephrine, and that can also contribute to the energizing effects that we associate with caffeine. I do want to point out that caffeine is not producing new energy. But rather, it's masking the feeling of tiredness or fatigue. So when it wears off, you might suddenly feel that fatigue that you were trying to suppress.

So since we all hopefully understand what we mean when we say caffeine now, teenagers are particularly vulnerable to its effects because they often have a lower body weight and a less developed tolerance compared to adults. And as a result, they're at higher risk for caffeine intoxication and the lower body weight tolerance also amplifies the pharmacologic effects per dose-- compared to adults-- of caffeine. Also, the adolescent brain is still developing into the early 20s, specifically in the regions that are involved in sleep regulation, impulse control, emotional processing.

 So, it tends to be a little bit more vulnerable to the disruptive effects of caffeine on those particular things related to like sleep architecture or neurobehavioral function. Teenagers typically have a poor awareness of what safe dosing is or what would be considered high risk consumption patterns for caffeine.

Host: Wow. You know, we're recording this in the morning and I am sipping on my own caffeinated beverage. Like, wow, I had no idea that's what's going on inside of me right now. Well, how much caffeine is considered too much for our adolescents?

Dr. Kelly Spence: Most literature is supporting a recommended maximum intake of about 2.5 to 3 milligrams per kilogram of body weight per day for adolescents. And that comes from Health Canada and the European Food Safety Authority. So for example, a typical teenager weighing about 50 kilograms is right around 110 pounds, and this would end up being somewhere between 125 and 150 milligrams of caffeine per day. But the United States is a little bit more conservative in its recommendations and says that daily intake should not exceed 100 milligrams per day. Most teenagers actually exceed these limits, especially when they're using energy drinks. And there's really not a recommended safe dose of caffeine.

 But just to give you some examples, your typical eight ounce cup of coffee could be anywhere from 95 to 200 milligrams of caffeine depending on the brew or the type. Most sodas are usually about 34 to 54 milligrams of caffeine per 12-ounce drink. And then, our energy drinks range anywhere from about 80 to 300 milligrams per 16 ounce can. So, there's a wide range there. But in general, less than 100 milligrams per day is the most common recommendation.

Host: Gotcha. So with this age group, what are the short term effects or risks of excessive caffeine use?

Dr. Kelly Spence: The most obvious effects that come to mind are things like insomnia, anxiety, excitement, restlessness. But specifically related to sleep, we see it's called increased sleep onset latency, meaning this is the time it takes to fall asleep. So for the average person, it should take about 10 minutes to fall asleep when you lay down with the intention of going to sleep. But with caffeine use, particularly if it's done in the afternoon or evening, can delay that. It can also lead to a reduced total sleep time. On average, we might see people getting less than six hours per night. Then, the sleep efficiency itself is disruptive. And then, when we have sleep disturbances like that, you end up with excessive daytime sleepiness, which can then go on to contribute to either conduct problems or issues at school, whether it's with the way we're getting along with other people or performing in class.

Related to the anxiety aspect of effects, there is a dose-dependent relationship here, meaning those that drink more caffeine are going to have a higher frequency of those anxiety symptoms. And we're actually seeing higher prevalence of anxiety no matter of the patient's sex or socioeconomic status when they use higher amounts of caffeine. And then, this is worse in people that already have underlying anxiety or other mood disorders, because they might be more vulnerable to those effects. Some other short-term risks with caffeine might be some nausea, abdominal pain, headaches, and you get the diuretic effect, meaning increased urination when you drink a lot of caffeine. And all of those things can be pretty disruptive to your day-to-day life.

 And then, the scary things people tend to think about are more of this cardiovascular type risks of caffeine use. And this is going to happen in folks that are having much higher consumption rates. This can increase the blood pressure, can cause palpitations, which are abnormal or fast heart rates. And then, it can prolong something called your QT interval, which is related to the electrical pathway of the heart. And this can increase the risk of abnormal heart rhythms that in severe cases could be fatal. But caffeine toxicity is pretty rare from beverages. I will point that out. Although, however, it's energy drinks and their supplements that are tending to be more linked to more serious events, especially if they're combined with alcohol or vigorous exertion.

Host: Well, that leads me into my next question about the longer term health impacts and what can parents and caretakers keep an eye out for or be aware of.

Dr. Kelly Spence: Yeah. So as far as the long-term effects of caffeine, the biggest one we've already alluded to a little bit is mostly related to persistent sleep dysfunction. And then, we also get increased risks of caffeine dependence or addiction. And there's no proven benefit on the brain or for psychomotor development. There was actually a study done in 2025 of middle school students, and they found that consuming greater than 100 milligrams of caffeine daily, which was that kind of max recommended dose, daily predicted, increases in conduct problems over time, mostly mediated by the daytime sleepiness that's happening because of chronic caffeine use contribution to just sleep dysregulation, and impact on sleep quality and alertness.

And then, interestingly, there was another longitudinal study showed that, with energy drinks specifically, they're associated with emotional and behavioral problems. And that these associations might be mediated not only by the sleep disruptions that are happening, but also unhealthy dietary habits like skipping breakfast that may come about due to choice of like energy drinks or caffeine drinks instead of a nutritious meal.

There really isn't any current evidence that's showing there's a long-term cardiometabolic risk in adolescents that use excessive amounts of caffeine. And this is unlike adults where higher caffeine consumption can show increased rates of high blood pressure, cholesterol problems, kidney problems, or diabetes. It does look like excessive caffeine use can worsen things like anxiety, migraine headaches, or other psychiatric symptoms. And then, many can also experience withdrawal symptoms when they stop drinking caffeine. So, this might be headaches, irritability, and decreased alertness, so kind of the opposite direction of caffeine intoxication.

I will point out that energy drinks are becoming more and more popular these days and we have pretty limited long-term data related to long-term health impacts with those specifically. And there are some unique risks with energy drinks, just because they have such a high caffeine content and other additives. And the data for those things is incompletely characterized at this point, especially as it relates to the long-term safety profile. But from what we can tell so far with systematic reviews and cross-sectional studies, there are associations with frequent energy drink and caffeine leading to psychological distress, increased suicidality, ADHD-type symptoms, depression and panic behaviors, as well as lower academic performance. But most of these studies, because of the way they're designed being cross-sectional, they're more like taking a snapshot in time rather than being conducted over the long term. So, it's really hard to say that there's any kind of causality or direct neurodevelopmental effects there.

But primarily, the studies are showing that the sleep disruption and behavioral problems is the main long-term thing to be aware of. And as far as what parents can be aware of, certainly you can see signs of caffeine intoxication. This is the restlessness, nervousness, anxiety, insomnia, sometimes flushing, frequent urination. Some people may only complain about GI complaints like nausea or pain. Some people can have fast heart rates, they might have abnormal heart rhythms. It might just look like they are going for periods being inexhaustible, which is pretty impressive if they're able to do that. But most of those symptoms are going to show up pretty shortly after the caffeine intake happens and with higher doses. So, what parents may be noticing is kind of just that frequent use causing problems with sleep and thus academic performance or increased anxiety tendencies than maybe they're used to seeing in their child. They might be a little bit more irritable, more so than you'd expect in the typical teenager mood swing. They may notice their child is complaining about more headaches than before, maybe they're sweating, maybe they're having increased bowel motility. That's a surprise one that many people don't think about. And then, in more severe cases, with excess caffeine intake, you could see things like vomiting, potentially seizures even, and that's going to be more with energy drinks or other caffeine supplements.

Host: Well, you touched on it a bit already, but how are energy drinks and these other highly caffeinated products we're seeing amplify the risk compared to maybe a standard cup of coffee or a soda or something like that?

Dr. Kelly Spence: Yeah. So, a lot of the amplified health risks and energy drinks or other supplements tend to be because they have higher caffeine concentrations compared to, you know, your standard cup of coffee or soda or the rapid consumption of those. Most people might just down an energy drink in 10 minutes, before they exercise or have an exam or something like that. And there may also be other stimulant type ingredients in the drinks, and many people aren't aware of that. So if you drink that energy drink really fast or in a really large quantity, you're going to have an increased risk of the acute toxicity, which might look like the fast heart rate, high blood pressure, abnormal heart rhythm, seizures, worsened anxiety or agitation.

 When you think about other stimulant products that might also be mixed in, those tend to have synergistic or more additive effects on the caffeine, which just increases the risks of the product. And it does look like in the literature that most case reports and reviews show that energy drinks versus standard coffee or soda are more frequently associated with a trip to the ER in a more severe outcome compared to the standard drink. And then. We already talked about some of the long-term effects of energy drinks or highly caffeinated products specifically. But typically, those that are having those types of drinks are already at higher risk of exceeding the safe daily caffeine limit compared to coffee or soda, just because there's so much more caffeine built in and people may drink more than one per day. But there's still a lot of room for research and more long-term data in that department.

Host: Well, knowing all of this now, how should parents talk to their teens about safe caffeine use?

Dr. Kelly Spence: That's a great question. And honestly, a lot of it comes down to modeling what is safe intake, as well as what safe alternatives might look like. So, I think, there's a real lack of awareness of what safe caffeine consumption looks like. I don't think people even realize that you can dose caffeine in milligrams. So, it might be teaching your teenager how to read the label and understand what the warning signs are of too much caffeine use, especially teaching them the dangers of mixing caffeine with other things like alcohol-- hopefully, they're not doing that. Anyway, that's a separate conversation-- or intense activity.

I also think it's really important to understand and communicate openly with why the teenager might be using caffeine. Are they doing this because they feel like they need energy? Are they doing it just because they like how it tastes? Is there a peer influence component? Because that can better shape the conversation and help whatever need might be going on in the adolescent.

 I also think going back to the modeling and the encouraging, we've got to think about other healthy lifestyle things like the importance of sleep hygiene, for example. Since caffeine tends to have such an effect on that, we need to teach our teenagers what is appropriate sleep hygiene and how do we maximize rest so you can perform well at school, on the sports field, in your job, whatever it is you're doing.

I also think emphasizing that there are unique risks of energy drinks or highly caffeinated products specifically is another specific area that parents can educate their children. Some kids may not even know the big difference between an energy drink versus a traditional drink. They may think it's actually a healthier alternative. They might equate it as being something in a can, like a soda over-the-counter. They may not even realize how much more caffeine they're getting.

Host: Right. Well, are there certain groups of teens, maybe with anxiety already or ADHD, anything like that, that are at a greater risk when it comes to caffeine use?

Dr. Kelly Spence: Yes. So, we've already kind of hinted at some of those things, but teenagers that may have a lower body weight might be a little bit more sensitive to the immediate caffeine effects. But certainly, folks that have underlying cardiac conditions or psychiatric problems could be at increased risk of having exacerbations of their mood-related symptoms or potentially cardiac risks like abnormal rhythms, blood pressure problems. Those that have seizure disorders may also be at increased risk of more severe effects. And then, for people that are taking stimulant medications, for example, for ADHD, caffeine's a stimulant so you're going to have additive effects in that population as well if you're drinking too much caffeine.

As far as other more specific conditions, asthma is one of the most common childhood illnesses we think about these days. But there's actually pretty limited data related to caffeine consumption in asthmatics. There's not an obvious association with an increased risk of your breathing-type symptoms. But apparently, and this is something I'm actually curious about myself, there may be a very small protective association on the airways with caffeine use. Granted, this would be very, very short-lived and mild. But I thought that was interesting.

I'll also point out that caffeine, there's a good chance that it'll interact with other prescription medications when we're thinking about asthma, things like theophylline, which is an older drug, but still out there. It may increase toxic effects. Although there are not many direct drug interactions between caffeine and the more commonly used asthma medications like inhaled steroids or your beta-agonist like albuterol. Those are not established. But high caffeine intake could potentiate their side effects, because of the stimulating nature of those medications. So, you might see more tremors and then again with the high heart rate.

Host: Closing out our conversation today, Doctor, what are some healthier alternatives that our teens could use if they still want some kind of boost or even perceived boost or energy or focus?

Dr. Kelly Spence: This is going to sound like a broken record, doctor speak, but it really comes down to just healthy lifestyle. So, I harped on adequate rest and good sleep hygiene a good bit. And we know that sleep deprivation is one of the major causes of fatigue and poor concentration, which is going to impact school and other performance in adolescents.

So, it's really important to talk about ways to sleep well. So, this might include limiting screen time, avoiding caffeine or excessive exercise too close to bedtime. It's also really important when folks are having fatigue and feeling like they have low energy to talk to your doctor about it, because sometimes those symptoms might be related to undiagnosed sleep apnea to ADHD, other endocrine problems or even depression that would require a different type of treatment.

 Other alternatives to caffeine would be balanced nutrition with regular meals and good hydration, because those things support sustained energy and better cognitive function. I've had some teenagers in my office ask me about protein supplements specifically, and those don't actually improve your performance if your dietary protein intake is good. So just good old-fashioned, eat your fruits, eat your vegetables, get a well-rounded diet, can go a long way, as well as regular physical activity, because this is going to improve your alertness, your mood, and your overall well-being. And if you're doing it regularly, hopefully, you're not feeling like you need caffeine to give you that boost to get that exercise.

We know that mental health is so important in not only our adolescents, but everybody. Learning good stress management and mindfulness techniques to reduce anxiety and improve focus can also be good alternatives, as well as time management and study skills for those that are in school can better enhance academic performance more so than caffeine. And hopefully, we don't have to rely on stimulants like that, and this could look like a lot of different things. Maybe we need some parent involvement, maybe we need tutors or even other school-based programs to see what works best for the child.

Host: Absolutely. Thank you so much for this fascinating conversation, Doctor. That was Dr. Kelly Spence, sharing valuable insights into the hidden risks of caffeine in adolescence. For more information, go to prismahealth.org/flourish. If you enjoyed this podcast, please share it on your social channels and check out the entire podcast library for more topics of interest to you. I'm Cailtin Whyte, and this is Flourish. Thank you for listening.