As a feature of CNNhealth.com, our team of expert doctors will answer readers' questions. Here's a question for Dr. Gupta.

CNN blogger, Beata, asks:

"Of those who have lived long lives, what is the common thread? What's the one thing I can do today that can make me live longer?"

Answer:

For well over a decade I've been investigating the answer to this question. The good news is there are actually a lot of small lifestyle changes you can make today that will add years to your life. For instance, flossing can add a year to your life – a whole year – just by adding to your daily routine. Turns out there's a pretty clear link between gum disease and heart disease. Flossing is your best bet at stopping that.

Here are a few more: A low-dose aspirin a day could add two years, and limiting your coffee intake to two cups a day could add another year. Simply checking blood pressure regularly could add one and a half years, and exercising three times a week could add three years. Cut work hours down to a manageable 40-50 hours a week and you add another one and a half years. Add it all up – and you have added a decade of functional life.

I will be the first to admit, it isn't always easy to practice what I preach, especially when it comes to the work-hour issue. But, we do know stress affects just about every part of our bodies. Our bodies simply start to shut down and become unable to tolerate the assault being placed on them every day.

Earlier this week I sat down with anti-aging expert Dan Buettner. He explores the world searching for longevity hotspots, known as blue zones, and looks for the lessons we can learn from them. One thing Buettner points out is that the people who live long lives in blue zones around the world are stressed out too. Yet they are still living disease free and often to 100 years old. The difference is they don't internalize their stress as most of us do. They all practice simple techniques to de-stress including praying, napping, even happy hour. Also meditating, which I have started, for 20 minutes every day and taking time for yourself every day can help.

In case you missed it, click here to hear more of my conversation with the world's leading anti-aging experts and get more tips to live a longer, healthier life.

By Caleb Hellerman
CNN Medical Senior Producer

Our special this weekend, “Another Day: Cheating Death,” includes the story of Laura Geraghty, a school bus driver in Massachusetts who survived a cardiac arrest that left her without a heartbeat for 57 minutes.  While the medical aspect is astounding, just as interesting is the story Geraghty told when she was revived.

She’d floated out of her body, and found herself in a world of incredibly bright light – heaven, she says. While there she saw her son, daughter, granddaughter and even her ex-husband – who wouldn’t take her hand when she reached out to him. Eventually she came back to the real world.

Many cultures and religions describe a vivid world on the border of life and death, but the classic modern near-death experience, or NDE, was described by Dr. Raymond Moody in his 1966 book, “Life After Life.”  While not every NDE includes the same features, among the most common – according to Moody – are bright lights, a tunnel, a sense of being out of the body and an intense feeling of peace and calm.

Most people who return from the verge of death with memories like this say it’s a life-changing experience. Many view it as direct proof of an afterlife – that the place they “visit” is the world we all will see after we die. But increasingly, near-death experience (a term coined by Moody) is being studied from the perspective of science.

Dr. Kevin Nelson, a neurologist at the University of Kentucky, believes an NDE is caused by REM activity, the same type of brain activity that’s linked to dreaming.  REM activity, says Nelson, can be triggered by intense stress or even lack of oxygen. In fact, he says many people experience an out-of-body experience during fainting episodes, or if they momentarily lose blood flow to the brain – as in a massive head rush.

Another intriguing experiment is underway at more than two dozen medical centers in the U.S. and Europe. It’s led by Dr. Sam Parnia, a critical care physician at New York Presbyterian-Cornell Hospital in New York. The setup is ingenuous. In hospital areas with critically ill patients, panels are hung from the ceiling to a height at which only someone floating near the ceiling could see what’s painted on top. If any patient reports a sense of floating - investigators can see if they accurately report what’s on the panel. Because the patients are being carefully monitored in ICUs, the experiment could also determine whether there are physical differences among people who report NDEs, and those who don’t.  

Parnia says he doesn’t know what he’ll find – but he does believe science can answer the question of what these experiences are really all about.  

What do you think? Can near-death experience be explained by what’s going on in the brain?

Watch “Another Day: Cheating Death” at 8 and 11 p.m. ET Saturday and Sunday.

Don’t miss, Dr. Gupta’s new book “Cheating Death”, available now wherever books are sold.  Be sure to follow – and tweet your medical miracle to – @sanjayguptacnn with #miracle and you could win a signed copy of the book and a Skype guest appearance from Dr. Gupta at your book club event.

Editor’s Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

By John Bonifield
CNN Medical News Producer

In college, I spent a summer in the Caribbean on an archaeology excavation. I remember submerging myself as deeply as I could in the ocean. I'd hold my breath as long as possible to admire the stunning underwater views of a shallow reef just off the beach at the site we were unearthing. I could never go more than about 45 seconds before surfacing for air. My lungs would burn as I hit the top of the water, gasping.

You probably know the feeling, too, if you've ever tried to hold your breath for as long as possible. Two or three minutes isn't unheard of for a lot of people. Expert breath-holders can go as long as seven minutes.

For Dr. Sanjay Gupta's upcoming documentary, "Another Day: Cheating Death," we've been taking a closer look at the human capacity to store oxygen. As it happens, oxygen is a double-edged sword when we die. Of course, we need it to sustain ourselves, but when a person's heart stops, the process of death is triggered. The body is designed to die, and to finish itself off; more oxygen is not what it wants. Get a cardiac arrest patient breathing again and you suddenly cheat death's plan. The body isn’t anticipating a new infusion of oxygen, and as the oxygen hits the cells and they begin to recover, they produce toxic molecules that are destructive.

Science is discovering innovative ways to mitigate the damage. Cooling patients down after a cardiac arrest seems to help. Chilled, their bodies can recover with less oxygen. New CPR techniques are also being utilized to keep the oxygen that's already in a victim's blood pumping through the body.

The concept is fascinating, and to make the point on television, we decided to spotlight synchronized swimmers. Their ethereal underwater dance is gorgeous to witness. They can remain submerged because there's a lot more oxygen in their blood than you might think, and they've trained themselves to utilize it efficiently. The synchronized swim team at Ohio State University is one of the best in the nation.

You'll see them featured in our program at 8 p.m. this Saturday and Sunday on CNN. When I visited the swimmers to watch a practice, they told me that although their routines sap them of air and energy, the performances actually help them to stay under longer. All that movement distracts them from thinking about how long they've gone without a breath. When I asked them to try it without moving, they still managed - impressively - some of them for more than two minutes - but it was harder, they said. Their trick: They went through the alphabet, letter by letter, associating words with each one until they could go no longer and had to surface for air.

Watch “Another Day: Cheating Death” at 8 and 11 p.m. ET Saturday and Sunday.

By David S. Martin
CNN Medical Senior Producer

North of the Arctic Circle, the weather is unforgiving, the population is scattered and the distances are immense. At the University Hospital of North Norway in Tromsø, the northernmost teaching hospital in the world, doctors routinely use a helicopter ambulance and fixed-wing plane to transport the most serious cases for care – or to bring emergency care to the patient. It’s all about buying time.

During a visit Tromsø, we shadowed Dr. Mads Gilbert, who heads the Department of Emergency Medical Services at the hospital, a small city surrounded by water and mountains. He describes trauma care in this part of the world as “cold, dark, distance and dangerous.” The cold poses its own challenges, and Dr. Gilbert and the team see a lot of hypothermia from ski accidents and people who’ve fallen out of fishing boats falling into the water.

Dr. Gilbert was on call 24 hours a day all week when we were there. He is 62, a rangy man with the energy and enthusiasm of someone half his age.

“What we do with emergency medicine - be it airway breathing, chest compressions, bleeding control, treating hypothermia - is to slow or even stop the death process. So it’s really the struggle between life and death and I always feel like we’re standing on the shore with the tide coming up. We’re trying to pull people from the tide of death and onto the dry land of life,” Gilbert said with a flourish.

Hours after we arrived, his team scrambled in the middle of the night, putting on jumpsuits and helmets and climbing aboard the helicopter ambulance. The temperature was just a degree or two above freezing as the helicopter lifted off and a chilling rain soon began to fall. A young man was suffering from an uncontrollable seizure, and the local doctor wasn’t sure whether it was an allergic reaction or something more serious. The helicopter ambulance team brought the patient back to the hospital.

By sending the helicopter, Dr. Gilbert and his team were able to get the patient to the hospital an hour and a half more quickly than a traditional ambulance. When we left that night, the patient was stable and resting as he awaited further neurological exams.

Gilbert says he expects the emergency teams to make close to 900 missions this year on the two aircraft. Norway started the Statens luftambulanse (National Air Ambulance System) in 1988. The goal is to reach 90 percent of the Norwegian population within 45 minutes. The service - all of Norwegian health care for that matter –is paid for by the government, through taxes. Gilbert is an outspoken proponent of national health care. Back from a mission, Gilbert joked that he didn’t ask to see a credit card before allowing the patient on board.

Gilbert and the other doctors at the University Hospital of North Norway have become perhaps the world’s leading experts treating cases of accidental hypothermia. To see their most remarkable rescue, a woman whose body temperature had dropped to 56 degrees, tune in to “Another Day – Cheating Death” this weekend, at 8 and 11 p.m. ET, Saturday and Sunday.

Has someone you know been airlifted to a hospital? What was the experience like?

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

By Caleb Hellerman
CNN Medical Senior Producer

Last week I traveled with Dr. Sanjay Gupta to Levittown, Pennsylvania, to meet Chris Brooks, a recent college grad who survived an unexplained cardiac arrest that stopped his heart for more than 15 minutes. That he survived – and without brain damage – is pretty incredible, and probably a tribute to the CPR performed by his father and the fact that he was cooled by emergency physicians at the local hospital, and at the University of Pennsylvania, where he was transferred afterwards.

What caught my attention the other day came when we asked Brooks whether doctors had figured out what caused the cardiac arrest in the first place. It’s a life-or-death question; Brooks now has a defibrillator implanted in his chest, and in the past six months it’s been triggered to shock him twice. In other words, his heart is stopping for no obvious reason.

But he hasn’t gone for a battery of tests that might provide an answer. The reason: no health insurance. He was covered by a family policy at the time of his cardiac arrest, but no more. “What we’re dealing now is insurance,” Brooks told us. “I’m 22 years old and not in college any more, so I don’t have insurance. I can’t see [my cardiologist] now. I want to, I guess, but I can’t.” His doctors are looking for a way to make it work, but in the best-case scenario it’s delaying those tests by two to three months - a reminder that even serious illness can slip through the cracks of the current health care system.

Health care bills moving through Congress might make life easier for Brooks; they would let people under 26 still be covered on their parents’ insurance. But the bills would also place a new burden on those 26 or older, by requiring them to purchase insurance or pay a penalty. Critics say people should be free to take the risk of going insurance-free, if they like – or if they can’t afford it.

Are you under 30 without health insurance? Do you have children in that boat? What would you do if there were a serious health crisis?

Programming note: See Chris Brooks’ story as part of Dr. Sanjay Gupta’s special, “Cheating Death,” October 17, 8 p.m.

By Leslie Wade
Producer CNN Medical News

This may sound corny, but I really enjoy spending time with my Mom. In August she turned 80 and could probably beat me in an arm wrestling match - no kidding, and I'm not exactly a weakling.

Jean Wade knows the secrets of healthy aging.

Mom is healthy and strong because she has truly taken care of herself physically, mentally and emotionally. You know all of the nagging you get each time you see your doctor for your annual check up? All the talk about not being a couch potato and eating yummy things like raw broccoli? Well, Mom actually listened and followed instructions.

Having Mom around means the world to me. Being around for your family or loved ones may be a gift worth considering. Here are some of Mom's health secrets, so perhaps we can all make it to 80 and beyond.

Back in the 60s Mom hosted a half hour TV show. One morning she interviewed an exercise instructor who was so impressive, Mom decided it was time to get back in shape. She's been exercising virtually every week since then. Unless she's sick, she gets some sort of weekly exercise: she walks, bikes, takes aerobics classes, swims laps in the pool and hits the ski slopes in the winter. From mid May to late September she rises with the sun and swims in the ocean off the Carolina coast: 400 strokes out from the beach and 400 strokes back, for a total of about 45 minutes. Exercising consistently for more than 45 years has a lot to do with her good posture, strong hand shake and brisk stride, but it's also a key component to her longevity.

We all know the benefits of exercise but let me remind you of a few. Consistent aerobic exercise strengthens the heart and keeps our blood vessels flexible and healthy. Exercise also helps keep cholesterol numbers, as well as blood pressure readings, in the healthy range - all good things when trying to keep heart disease at bay. Exercise is good for brain health, perhaps making us sharper mentally and reducing the risk for dementia and stroke. Exercise helps enhance our moods and may have a positive effect on our sex lives.

Good nutrition is about as important to Mom as exercise. She started cooking at age 13, when her mom went off to work in the factories during World War II, and has never stopped. She reads books about nutrition, has notebooks and cookbooks filled with healthy recipes and subscribes to health newsletters. Even during vacation and holidays, Mom eats a balanced diet with plenty of fruits and vegetables. She eats meat, but not every day, and the cuts are always lean. You rarely find fatty hamburger or fried chicken on her table and I don't think she's ever bought chips or soda except when having a party.

How can eating right help all of us stay healthy? Low fat meals filled with fruits, vegetables and whole grains can help lower our risk for heart disease, certain cancers, type 2 diabetes and keep our waistlines trim. I know it's tempting to eat fast food and high-fat meals, especially when on the run, but eating right may help keep your heart pumping longer, your blood vessels coursing more smoothly and your cholesterol down.

There is no doubt that having a good marriage can reduce stress. Having my dad around for the last 50+ years has not only been entertaining for Mom - he's a very funny fellow - but his kindness and love are like a balm to her, plus he forgives easily. Studies show that reducing our stress level is good for our bodies and minds. When we're stressed out we release chemicals that doctors believe play a role in forming plaques that clog blood vessels in our brains (making us more prone to losing mental capacity as we age) and around our hearts (leading to coronary artery disease). Stress has been linked to high blood pressure, heart disease and depression. So good marriage or not, reducing stress should be a priority.

No one can predict the future of course, but it wouldn't surprise me if the family gathered to celebrate mom's 100th birthday in 20 years. She's going strong and showing few signs of slowing down. Her bones are as strong as someone in their 20s, her cholesterol and blood pressure numbers are low and her resting heart rate matches that of many a seasoned athlete. She has lived life wisely by eating well, exercising often and keeping an eye on her stress levels. I for one plan to take a page from her playbook: I may not be able to beat my kids in an arm wrestling match when I'm 80 but I sure hope I'm around to give it a try.

What helps motivate you to exercise and stay healthy. How do you stay on course?

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

Dr. Sanjay Gupta says his upcoming birthday motivated him to launch the fitness forum with viewers. He wants himself, and America, to get in the best shape of their lives.

By Dr. Sanjay Gupta
CNN Chief Medical Correspondent

Today, I am starting something I have wanted to do for a very long time.

Using this blog and my @SanjayGuptaCNN twitter account, I am going to try to harness some of the best practices people employ every day to stay in the best shape of their lives.

Truth is, there are hundreds of sites like this, so I want to make this one different. First of all, I am hoping it becomes a living, breathing forum that users, like you, use to share your best health and fitness tips. I learn new things every day from CNN bloggers and Tweeters. You all are a great resource of information.

I am also going to call on my friends and others I find inspiring to help as well.

For example, @JoePerez helped create something called the Daily Plate, which partners with the non-profit cancer foundation LIVESTRONG, where I sit on the board of directors. After surveying lots of different ways of tracking diets, I think this is one of the best. I will introduce you to Joe and the Web site.

There are also sites out there that will start to help you heart rate train. After doing lots of research, I believe this is one of the most effective and efficient ways of training. Ironically, my friends who listened to this recommendation from me say they work out less intensely and still increase their fitness more than before.

Speaking of LIVESTRONG, I hope to get my pal @LanceArmstrong to weigh in. Admittedly, he is a professional athlete who will be pretty busy training for a big race in July. After that, though, I hope he will share with you some of the great tips he has given me over the years.

Also well-known trainer, and friend of mine, @JillianMichaels who can provide logical, useful suggestions that can be applied to lots of different situations. I also hope to get tips from @RichRoll. We have met only via twitter, but he is living proof that you can go from being a 38-year-old who hardly ever works out to someone who is in fantastic shape, an ultraman in fact, and is biologically younger than he was 10 years ago.

Most of all, this will be a four-month forum dedicated to getting people in terrific shape.

While smaller waists and less weight are things that will inevitably occur as you start incorporating these tips into your life, the real goal is a longer, more functional and exceptional life – free of disease and dysfunction.

I am a neurosurgeon and a reporter for CNN, who has three kids. I have a fairly active travel schedule. I tell you all that, because, like most people, I am busy. Yet, it can still be done.

So join me right here and on my Twitter page. Also, let's keep track of each other’s tips under the hashtag #1023 - which just so happens to be the date of a very big birthday for me.

Four months from now, I hope, we can all celebrate what we have done for our bodies and for our health.

By Madison Park
CNNHealth Writer

I was 22 years old when I plucked a gray strand from my tangled black hair.

I showed my mom the strange silver hair, and she shot me the "I-told-you-so" look.  She always told me that watching TV or being on the computer  would make me prematurely gray.

Her evidence: Every computer engineer she knew got gray in her 30's, but she only knew one computer engineer. So I dismissed this as a kooky theory.

But my gray encounter sparked a curiosity. I’ve seen an occasional silver strand and sometimes a scattering of gray hairs on students, teens and even kids.  One mother wrote to CNNhealth after spotting a strand of gray hair on her 3½-year-old daughter.

Could younger people be graying earlier?  Could it be hereditary or are there environmental factors - like  TVs and computer screens– as my mother suggested?

While researchers have no definitive answers, scientists in Japan say that "genotoxic stress" damages cells which are responsible for hair color. When these melanocyte stem cells die, we get irreversible graying, according to a report released this month in the journal Cell.

Our DNAs are under constant attack by chemicals, ultraviolet light and ionizing radiation, said one of the authors, Dr. Emi Nishimura of Kanazawa University.

In nature, ionizing radiation can come from cosmic rays from the sun and stars, and radioactive materials in rocks and soil, according to the National Institutes of Health. But ionizing radiation also comes from man-made sources, such as X-rays, televisions, smoke detectors, building materials, tobacco smoke, and mining and agricultural products, such as granite, coal, and potassium salt.

"It is estimated that a single cell in mammals can encounter approximately 100,000 DNA damaging events per day,” Nishimura wrote in an email. "But is not clear which kind of sources for genotoxic stress are the major contributors to aging or hair graying."

In Nishimura’s experiment, 7-to-8-week-old brown and black mice were exposed to whole-body X-rays. "If we try lower doses (of ionizing radiation), you can see a salt and pepper pattern in their hair," Nishimura said.  "With a bit higher doses, you can see more white hair.  Most of the hair became white."

While studies in mice don't always apply to humans, they can provide scientific clues.

“We discovered that hair graying, the most obvious aging phenotype, can be caused by the genomic damage response" wrote the researchers from the Center for Cancer and Stem Cell Research at Kanazawa University in Japan. The results on mice "suggest that physiological hair graying can be triggered by the accumulation of unavoidable DNA damage."

I haven't seen another gray hair in years, but I'm on the lookout.

By Caleb Hellerman
CNN Medical Senior Producer

Last fall, I started getting worried about my father - just a vague sense something wasn’t right. He’d tell the same story, gripe about the same thing, one too many times. Plus, he’s 82 years old. My mother and brother said he was fine, but then something tipped me over the edge: After more than 50 years running his own small company, my father had decided to sell the business, and I was helping with paperwork. He’d been moaning and groaning about it forever, but when I sat down to put together a few spreadsheets – well, it was easy. I thought: he couldn’t handle this?

Maybe it was a medication. Maybe stress, or a touch of depression – all things that can mimic the early stages of dementia. Or maybe my mom and brother were right. I wasn’t sure where to start, so I called Dr. Thomas Perls, a gerontologist – a specialist in treating older people. I’d interviewed him before, and said I needed a favor. Where should I take my dad? What questions should I ask?

Dr. Perls told me I really ought to take him to a gerontologist, who wouldn’t focus on an aching hip, or a memory problem, or incipient diabetes – but all of it, together. And because I was worried about memory loss, someone who could order a detailed neuropsychological exam. And then I took a big step: I told my dad I was worried about him…. and he said sure, he’d see a new doctor as long as I set it up.

But that was January, and now it’s April. Something always came up. Or maybe I didn’t want to go, myself. But then I noticed that today is something called “Take a Loved One to the Doctor Day.” It’s organized by radio superstar Tom Joyner, to encourage African-Americans to get regular checkups. We’re not African-American – but when I got the flier and saw the headline, how could I ignore what’s going on in my own family?

So today, I’m calling about that appointment. Maybe – I hope – it won’t be any big deal. But it’s my dad, and I owe it to him.

Have any advice about finding the right help for an aging parent?

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

As a new feature of CNNhealth.com, our team of expert doctors will answer readers’ questions. Here’s a question for Dr. Gupta.

Asked by Bill, Dawsonville, Georgia

“I am a pretty healthy 50-year-old guy, but I notice a lot of my friends and colleagues in the same age group are starting to get heart disease and prostate cancer. What is your advice for men wanting to stay a step ahead of potential health concerns?”

Answer:

Thanks for the question. I’m happy to hear you’re interested in health prevention during the prime years of your life. You might be surprised to know that many men don’t get regular health check-ups. It’s interesting when you think about it: Many men tend to focus on their outer appearance around age 50 - get new clothes, new haircut maybe. But when it comes to regular health screenings, they often skip them! The problem is, age 50 is when potential health issues develop.

All men (and women) should be getting annual physicals and screenings for cancer and heart disease. Heart disease is the No. 1 killer for men in the United States and it is often preventable. Keeping your weight down and your vital signs at a healthy level are two of the easiest things a person can do to reduce their risk. In addition to annual check-ups with your general physician, get your eyes examined at least once every two years.

If you’re like me, you might have trouble remembering when your last appointment was. But no excuses! One easy solution is to schedule your annual check-up for the week of your birthday. You’ll likely never forget.

One last piece of advice, don’t let fitness be the first thing to fall off your schedule. It always seems to, especially when life gets busy. But exercise is truly the single best thing a person can do for a long health life. It is not only good for your heart, your brain, and your body weight but also relieves stress. Some studies even show that people who work out are overall happier than those who don’t.

Bottom line: Investing time in your health now, will pay off years down the road. Best of luck, Bill!