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Researchers Recommend at Least 30 Minutes of Nature Time Per Week

It's no secret that spending time in nature can be good for your health. Now, researchers, who published their results in the journal Nature Scientific Reports, say they’ve found the minimum dose of nature time required to reap the benefits: 30 minutes a week.

Earlier studies concluded that spending time in green and blue spaces like the park and the beach may lower blood pressure, reduce stress and anxiety, and even keep us alive longer. But “nature” can be kind of a slippery concept. There’s no scientific consensus on what “nature” is, which means that each experiment has relied on its own definition. And while those studies agreed that nature time is good medicine, few have tried to identify the right dose.

To address the latter, a team of researchers surveyed 1538 residents of the city of Brisbane, Australia. The participants were between the ages of 18 and 70 years old and were evenly mixed in age, gender, income, and socioeconomic status. The survey was pretty holistic, asking participants about not only their physical and mental health but also their work hours, family situations, exercise habits, and, of course, time spent outdoors. And rather than defining terms, the researchers simply asked participants to answer based on what they considered "outdoor green space."

The survey results certainly supported earlier research; even after controlling for factors like exercise and socioeconomic status, nature time was associated with better health. But a monthly five-minute stroll across the city green wasn’t enough. To really see nature’s salutary effects, participants had to log at least 30 minutes per week. Thirty minutes of park time per week really isn’t that much, if you think about it, but it does require effort, interest, and resources. Forty percent of respondents said they hadn’t visited a park in the last week at all, let alone for a half-hour.

Lead author and University of Queensland biologist Danielle Shanahan sees this as great news. "If everyone visited their local parks for half an hour each week, there would be 7 percent fewer cases of depression and 9 percent fewer cases of high blood pressure," she said in a press statement.

"Given that the societal costs of depression alone in Australia are estimated at $A12.6 billion a year, savings to public health budgets across all health outcomes could be immense," she said.

The results do come with one big caveat. Survey responses showed a correlation between nature time and better health, but they didn't show causation. It’s possible, for example, that people with depression and high blood pressure have a harder time getting to the park; depression can make it very hard to leave the house, and high blood pressure could be worsened by a nonstop schedule. Just the same, these results are encouraging, and surely a little time in a soothing green space is a good thing.

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Aflac's Robotic Duck Comforts Kids with Cancer
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Aflac

Every year, close to 16,000 children in the U.S. are diagnosed with cancer. That news can be the beginning of a long and draining battle that forces kids and their parents to spend large amounts of time with medical providers, enduring long and sometimes painful treatments. As The Verge reports, a bit of emotional support during that process might soon come from an unlikely source: the Alfac duck.

The supplemental insurance company announced at the 2018 Consumer Electronics Show (CES) that it has partnered with the medical robotics company Sproutel to design and manufacture My Special Aflac Duck, a responsive and emotive sim-bird intended exclusively for children undergoing cancer treatment.

When a child cuddles the fuzzy robotic duck, it can cuddle back. It reacts to being cradled and stroked by quacking or moving its head. Kids can also touch special RFID chips emblazoned with emoji on the duck's chest to tell it how they’re feeling, and the device will mimic those emotions.

But the duck isn’t solely for cuddling. In “IV Mode,” which can be switched on while a child is undergoing IV therapy, the duck can help the user relax by guiding them through breathing exercises. Accessories included with the toy also allow children to "draw blood" from the duck as well as administer medication, a kind of role-playing that may help patients feel more comfortable with their own treatments.

Aflac approached Sproutel with the idea after seeing Sproutel’s Jerry the Bear, a social companion robot intended to support kids with diabetes. Other robotic companions—like the Japanese-made seal Paro and Hasbro's Joy for All companion pets for seniors—have hinted at a new market for robotics that prioritize comfort over entertainment or play.

My Special Aflac Duck isn’t a commercial product and won’t be available for retail sale. Aflac intends to offer it as a gift directly to patients, with the first rollout expected at its own cancer treatment center in Atlanta, Georgia. Mass distribution is planned for later this year.

[h/t The Verge]

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The Body
12 Fantastic Facts About the Immune System
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The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

If it weren't for our immune system, none of us would live very long. Not only does the immune system protect us from external pathogens like viruses, bacteria, and parasites, it also battles cells that have mutated due to illnesses, like cancer, within the body.

Here are 12 fighting facts about the immune system.

1. THE IMMUNE SYSTEM SAVES LIVES.

The immune system is a complex network of tissues and organs that spreads throughout the entire body. In a nutshell, it works like this: A series of "sensors" within the system detects an intruding pathogen, like bacteria or a virus. Then the sensors signal other parts of the system to kill the pathogen and eliminate the infection.

"The immune system is being bombarded by all sorts of microbes all the time," Russell Vance, professor of immunology at University of California, Berkeley and an investigator for the Howard Hughes Medical Institute, tells Mental Floss. "Yet, even though we're not aware of it, it's saving our lives every day, and doing a remarkably good job of it."

2. BEFORE SCIENTISTS UNDERSTOOD THE IMMUNE SYSTEM, ILLNESS WAS CHALKED UP TO UNBALANCED HUMORS.

Long before physicians realized how invisible pathogens interacted with the body's system for fighting them off, doctors diagnosed all ills of the body and the mind according to the balance of "four humors": melancholic, phlegmatic, choleric, or sanguine. These criteria, devised by the Greek philosopher Hippocrates, were divided between the four elements, which were linked to bodily fluids (a.k.a. humors): earth (black bile), air (blood), water (phlegm) and fire (yellow bile), which also carried properties of cold, hot, moist, or dry. Through a combination of guesswork and observation, physicians would diagnose patients' humors and prescribe treatment that most likely did little to support the immune system's ability to resist infection.

3. TWO MEN WHO UNRAVELED THE IMMUNE SYSTEM'S FUNCTIONS WERE BITTER RIVALS.

Two scientists who discovered key functions of the immune system, Louis Pasteur and Robert Koch, should have been able to see their work as complementary, but they wound up rivals. Pasteur, a French microbiologist, was famous for his experiments demonstrating the mechanism of vaccines using weakened versions of the microbes. Koch, a German physician, established four essential conditions under which pathogenic bacteria can infect hosts, and used them to identify the Mycobacterium tuberculosis bacterium that causes tuberculosis. Though both helped establish the germ theory of disease—one of the foundations of modern medicine today—Pasteur and Koch's feud may have been aggravated by nationalism, a language barrier, criticisms of each other's work, and possibly a hint of jealousy.

4. SPECIALIZED BLOOD CELLS ARE YOUR IMMUNE SYSTEM'S GREATEST WEAPON.

The most powerful weapons in your immune system's arsenal are white blood cells, divided into two main types: lymphocytes, which create antigens for specific pathogens and kill them or escort them out of the body; and phagocytes, which ingest harmful bacteria. White blood cells not only attack foreign pathogens, but recognize these interlopers the next time they meet them and respond more quickly. Many of these immune cells are produced in your bone marrow but also in the spleen, lymph nodes, and thymus, and are stored in some of these tissues and other areas of the body. In the lymph nodes, which are located throughout your body but most noticeably in your armpits, throat, and groin, lymphatic fluid containing white blood cells flows through vein-like tubules to escort foreign invaders out.

5. THE SPLEEN HELPS YOUR IMMUNE SYSTEM WORK.

Though you can live without the spleen, an organ that lies between stomach and diaphragm, it's better to hang onto it for your immune function. According to Adriana Medina, a doctor who specializes in hematology and oncology at the Alvin and Lois Lapidus Cancer Institute at Sinai Hospital in Baltimore, your spleen is "one big lymph node" that makes new white blood cells, and cleans out old blood cells from the body.

It's also a place where immune cells congregate. "Because the immune cells are spread out through the body," Vance says, "eventually they need to communicate with each other." They do so in both the spleen and lymph nodes.

6. YOU HAVE IMMUNE CELLS IN ALL OF YOUR TISSUES.

While immune cells may congregate more in lymph nodes than elsewhere, "every tissue in your body has immune cells stationed in it or circulating through it, constantly roving for signs of attack," Vance explains. These cells also circulate through the blood. The reason for their widespread presence is that there are thousands of different pathogens that might infect us, from bacteria to viruses to parasites. "To eliminate each of those different kinds of threats requires specialized detectors," he says.

7. HOW FRIENDLY YOU'RE FEELING COULD BE LINKED TO YOUR IMMUNE SYSTEM.

From an evolutionary perspective, humans' high sociability may have less to do with our bigger brains, and more to do with our immune system's exposure to a greater number of bacteria and other pathogens.

Researchers at the University of Virginia School of Medicine have theorized that interferon gamma (IG), the immune cytokine that helps the immune system fight invaders, was linked to social behavior, which is one of the ways we become exposed to pathogens.

In mice, they found IG acted as a kind of brake to the brain's prefrontal cortex, essentially stopping aberrant hyperactivity that can cause negative changes in social behavior. When they blocked the IG molecule, the mice's prefrontal cortexes became hyperactive, resulting in less sociability. When they restored the function, the mice's brains returned to normal, as did their social behavior.

8. YOUR IMMUNE SYSTEM MIGHT RECRUIT UNLIKELY ORGANS—LIKE THE APPENDIX—INTO ITS SERVICE.

The appendix gets a bad rap as a vestigial organ that does nothing but occasionally go septic and create a need for immediate surgery. But the appendix may help keep your gut in good shape. According to Gabrielle Belz, professor of molecular immunology at the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, research by Duke University's Randal Bollinger and Bill Parker suggests the appendix houses symbiotic bacteria that are important for overall gut health—especially after infections wipe out the gut's good microbes. Special immune cells known as innate lymphoid cells (ILCs) in the appendix may help to repopulate the gut with healthy bacteria and put the gut back on track to recovery.

9. GUT BACTERIA HAS BEEN SHOWN TO BOOST IMMUNE SYSTEMS IN MICE.

Researchers at the University of Chicago noticed that one group of mice in their lab had a stronger response to a cancer treatment than other mice. They eventually traced the reason to a strain of bacteria—Bifidobacterium—in the mice's guts that boosted the animals' immune system to such a degree they could compare it to anti-cancer drugs called checkpoint inhibitors, which keep the immune system from overreacting.

To test their theory, they transferred fecal matter from the robust mice to the stomachs of less immune-strengthened mice, with positive results: The treated mice mounted stronger immune responses and tumor growth slowed. When they compared the bacterial transfer effects with the effects of a checkpoint inhibitor drug, they found that the bacteria treatment was just as effective. The researchers believe that, with further study, the same effect could be seen in human cancer patients.

10. SCIENTISTS ARE TRYING TO HARNESS THE IMMUNE SYSTEM'S "PAC-MAN" CELLS TO TREAT CANCER.

Aggressive pediatric tumors are difficult to treat due to the toxicity of chemotherapy, but some researchers are hoping to develop effective treatments without the harmful side effects. Stanford researchers designed a study around a recently discovered molecule known as CD47, a protein expressed on the surface of all cells, and how it interacts with macrophages, white blood cells that kill abnormal cells. "Think of the macrophages as the Pac-Man of the immune system," Samuel Cheshier, lead study author and assistant professor of neurosurgery at Stanford Medicine, tells Mental Floss.

CD47 sends the immune system's macrophages a "don't eat me" signal. Cancer cells fool the immune system into not destroying them by secreting high amounts of CD47. When Cheshier and his team blocked the CD47 signals on cancer cells, the macrophages could identify the cancer cells and eat them, without toxic side effects to healthy cells. The treatment successfully shrank all five of the common pediatric tumors, without the nasty side effects of chemotherapy.

11. A NEW THERAPY FOR TYPE 1 DIABETES TRICKS THE IMMUNE SYSTEM.

In those with type 1 diabetes, the body attacks its own pancreatic cells, interrupting its normal ability to produce insulin in response to glucose. In a 2016 paper, researchers at MIT, in collaboration with Boston's Children's Hospital, successfully designed a new material that allows them to encapsulate and transplant healthy pancreatic "islet" cells into diabetic mice without triggering an immune response. Made from seaweed, the substance is benign enough that the body doesn't react to it, and porous enough to allow the islet cells to be placed in the abdomen of mice, where they restore the pancreatic function. Senior author Daniel Anderson, an associate professor at MIT, said in a statement that this approach "has the potential to provide [human] diabetics with a new pancreas that is protected from the immune system, which would allow them to control their blood sugar without taking drugs. That's the dream."

12. IMMUNOTHERAPY IS ON THE CUTTING EDGE OF IMMUNE SYSTEM RESEARCH.

Over the last few years, research in the field of immunology has focused on developing cancer treatments using immunotherapy. This method engineers the patient's own normal cells to attack the cancer cells. Vance says the technique could be used for many more conditions. "I feel like that could be just the tip of the iceberg," he says. "If we can understand better what the cancer and immunotherapy is showing, maybe we can go in there and manipulate the immune responses and get good outcomes for other diseases, too."

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