Welcome to Paging, Dr. Gupta. Thank you so much for joining us. I love listening to all your comments and your questions. It really gives me a sense of what's on your mind. My producer, Jennifer, is back with us today. Who do we have first?

'Hi, Sanjay. Today we have a 14-year-old calling from Orlando, Florida, with a great question about bathroom air dryers.

Hello, my name is David and my question for the podcast is are air dryers safe? Like do they have a filter where they filter the bacteria out?

'Okay, David, 14-year-old David, thank you for calling in. That's a great question. Look, sometimes you gotta use a public restroom. I don't think anyone wants to do that, but sometimes it's just obviously inevitable. It may feel stressful because public restrooms may feel like they're full of pathogens, like bacteria, maybe even viruses. So we know that we need to wash our hands after using the bathroom wherever we are. What you may not know is that it's also critically important to dry your hands after washing them because it helps decrease the volume of germs on our hands and also because bacteria can be spread way more easily when our hands are wet. Now, if you're in a public restroom, there are often several options to dry you hands afterward. Warm air dryer, jet air dryer and or paper towels, which is the most hygienic? We'll get into that after this short break.

'Okay David, back to your question on the hygiene and safety of air dryers. So first of all let's just start with some basics. How do air dryers work to dry our hands? Well, conventionally, there are two types of air dryers, traditional warm air dryers and jet air dryers. Both of them draw in the surrounding air. I'm going to come back to that point, but they both draw in the surrounding through an electric motor in the dryer. In the traditional warm dryer, the air then goes through a heater and comes out a wide nozzle. A jet air dryer forces air out at a high speed to sort of push droplets off of your hands. But again, I want to emphasize this point, the air that dries your hands from both jet air dryers and warm air dryers is air that is pulled from the public restroom. And the reason that's worth emphasizing is because it can be potentially problematic. Oftentimes there can be aerosolized microbes in the bathroom air. If a toilet is flushed without shutting the lid, that flush can disperse a fine mist of aerosolized microbes into the air. And that's where bacteria and viruses potentially come from. So that means dryers can potentially spread the bacteria and virus onto your newly washed hands and they can undo what you just did to get rid of the germs. In fact, researchers did a test a few years ago. What they did is they put petri dishes in public bathrooms under two different conditions. In the first, they exposed the petri dish to bathroom air for two minutes. And in the second, the petri dishes were placed under air dryers for 30 seconds. It turns out when petri dish were left in the bathroom for 2 minutes, they grew an average of about 1 bacterial colony per dish. But when the petri were placed in a hair dryer for 30 seconds, they grew an average of 60 colonies per dish. Now, another thing that David raised was filters. Many modern hair dryers do have HEPA filters, although older or less expensive models may not have them. But if an air dryer does have a filter, it also needs to be maintained and that filter needs to replaced periodically. So all of that is the background to answering the question, what is the cleanest way to dry your hands after washing them: hot air dryer, jet air dryer or paper towels? There's actually been a review of this published in the National Library of Medicine which analyzed 12 studies from 1970 to 2011 that studied all these different ways to dry your hands. And the review was evaluating hand-drying methods using three criteria: drying efficiency, removal of bacteria, and prevention of cross-contamination. And their conclusion was that paper towels were the winner from a hygiene standpoint. In fact, the review recommended that paper towel should be used to dry hands in locations like hospitals and clinics. Because paper towels can dry your hands faster and also directly remove bacteria from your washed hand when the air dryers cannot. Among all the options, incidentally, jet air dryers had the worst hygiene performance. A 2015 study found that jet air-dryers spread 60 times more viruses than hot air dryers and 1,300 times more than paper towel on average. So I know it's not necessarily great for the environment to be using paper towel, but if the question is simply about hygiene, then that's going to be your best bet. And one last tip before you go, carry some hand sanitizer with you in case there are only air dryers in any public restroom you find yourself in. David, I hope this answers your question about dryers, about how to keep your hands clean and dry when you walk out of a public restroom. Thanks so much for calling in. Okay, we're going to take a quick break here, but when we come back, what to make of this growing trend of plasma donation across the country? What is it? And are there any potential health consequences? We'll get into it after the break.

And we are back with paging Dr. Gupta. Jennifer, who do we have next?

Okay, Sanjay, we have a nurse practitioner asking about plasma donation. Now, she's seeing a growing number of people in her community requesting medical authorization to donate plasma, so here's what she wants to know.

Hi Dr. Sanjay, my name is Deepa. I am writing a question regarding the increasing trend of plasma donation in our community. I would like to know, better understand the reasons behind this search, the recommended frequency of plasma donations, potential health consequences, and any safety concerns with the frequent donation of plasma, especially with people with mental health disorders or people who take a lot of medication.

'Okay Deepa, thank you so much for your observation. Thank you for your question. Look, there has been an uptick in plasma donation not only in your community, but all over the country. In fact, according to a U.S. Plasma industry report, Americans sold about 62.5 million liters of their plasma in 2025. That was more than a 30% jump in the volume of plasma collected since 2022. So why? What's going on here? Well, part of this is just the economy. More and more Americans are struggling to make ends meet in this economy. We have sluggish job growth, higher consumer prices, lower rates of savings. And what we're hearing as a result is that college students in particular have reported selling their plasma to cover some of those costs. Middle class Americans say they need the extra money to cover their expenses. According to the industry report, Americans receive about $65 per plasma donation. Which added more than $4.7 billion to American's household income last year. So a lot of this is just simply about money. But let's go back to the basics here. What is plasma? What is its role? Plasma is essentially the liquid part of your blood. It's a pale yellow color. Makes up around 55% of your blood's volume and it transports red and white blood cells and platelets around your body. It's basically 92% water, 7% or so proteins like antibodies and coagulation factors, and 1% hormones and vitamins and salt enzymes and other compounds. Like donated blood, donated plasma can be a medical lifesaver. For example, plasma donation can help people with rare and chronic diseases, can help people who are cancer patients, people who have clotting factor disorders. A plasma transfusion, in essence, can help increase blood volume. Which can restore blood pressure, replenish electrolytes, and other vital components. The United States, incidentally, is a major supplier of human plasma, contributing approximately 70% of the global plasma used for plasma-derived medicinal products. Not just anyone can donate plasma. Certain experiences, health conditions, or medications may temporarily, or sometimes even permanently, prevent a person from donating plasma. But I want to get to your question, Deepa. People with certain health conditions and people who take a lot of medications may not even pass the initial health screening. So how do you donate plasma and what does the process look like? Well, for starters, there are usually local plasma donation centers and you can contact them to find out if you initially qualify. Each center may have its own specific process. Now, once you make an appointment, there will be a health screening and a medical exam. Once you've passed that, the staff will place a needle in your arm, take blood, and that blood will go to a specialized machine that separates out the plasma. The rest of your blood, incidentally, is then returned to your body. The amount you donate can range from 625 mLs to 880 mL depending on your weight. The staff will then give you some saline as well to help you maintain circulation during the donation. Whole process takes typically around two hours if it's your first time donating plasma Now, Deepa, long term health consequences of frequent plasma donation. Well, good news here is that according to the FDA, several studies have shown that there are no long-term side effects for people who donate plasma regularly and long- term, again, if they've passed those initial medical requirements. The FDA has set a limit on how often a person can donate plasma. Donors shouldn't give more than twice a week or more than once in a 48-hour period. No more than twice a week. More than once in a 48-hour period. Your blood volume typically returns to normal levels in 48 hours. You gotta make sure you stay hydrated during that time. One study has shown that donating plasma too frequently could result in potential issues that could affect the quality of the plasma and maybe even the health of the donor. So I guess the bottom line is, according to the FDA guidelines, a person can donate plasma frequently and over the long term, but it doesn't necessarily mean they should. American Red Cross, for their part, recommends plasma donors give once every 28 days, up to 13 times a year, no more than that. Deepa, thank you so much for your question. Donating plasma is important. It can help a lot of people. It's good for our fellow humans who urgently need this resource. But you gotta do it responsibly. Thanks again for calling in. And that's a wrap for today's episode. Thanks to all of you for sending in your health questions. Remember, no question is too big or too small. I love hearing from you. So keep them coming. We might just answer your question on our next show. Reach out to us, record a voice memo, email it to pagingdrgupta@cnn.com. That's pagingdrgupta@cnn.com or give us a call 470-396-0832 and leave a message. Thanks for listening.