TIME Mental Health/Psychology

You Asked: Does Laughing Have Real Health Benefits?

Illustration by Peter Oumanski for TIME

Your body could use a belly laugh

It may not be the best medicine. But laughter’s great for you, and it may even compare to a proper diet and exercise when it comes to keeping you healthy and disease free.

That’s according to Dr. Lee Berk, an associate professor at Loma Linda University in California who has spent nearly three decades studying the ways the aftershocks of a good laugh ripple through your brain and body.

Berk says your mind, hormone system and immune system are constantly communicating with one another in ways that impact everything from your mood to your ability to fend off sickness and disease. Take grief: “Grief induces stress hormones, which suppress your immune function, which can lead to sickness,” he says. Hardly a week goes by without new research tying stress to another major ailment.

Why mention stress? “Because laughter appears to cause all the reciprocal, or opposite, effects of stress,” Berk explains. He says laughter shuts down the release of stress hormones like cortisol. It also triggers the production of feel-good neurochemicals like dopamine, which have all kinds of calming, anti-anxiety benefits. Think of laughter as the yin to stress’s yang.

Thanks largely to these stress-quashing powers, laughter has been linked to health benefits ranging from lower levels of inflammation to improved blood flow, Berk says. Some research from Western Kentucky University has also tied a good chuckle to greater numbers and activity of “killer cells,” which your immune system deploys to attack disease. “Many of these same things also happen when you sleep right, eat right, and exercise,” Berk says, which is why he lumps laughter in with more traditional healthy lifestyle activities.

Berk has even shown that laughter causes a change in the way your brain’s many neurons communicate with one another. Specifically, laughter seems to induce “gamma” frequencies—the type of brain waves observed among experienced meditators. These gamma waves improve the “synchronization” of your neuronal activity, which bolsters recall and memory, Berk says.

How does laughter accomplish all this? That’s where things get murky, says Dr. Robert Provine, a neuroscientist at the University of Maryland, Baltimore County and author of Curious Behavior: Yawning, Laughing, Hiccupping, and Beyond.

Provine calls himself a “reserved optimist” when it comes to laughter’s health-bolstering properties. “One of the challenges of studying laughter is that there are so many things that trigger it,” Provine explains. For example, you’re 30 times more likely to laugh around other people than when you are by yourself, he says. Social relationships and companionship have been tied to numerous health benefits. And so the social component of laughter may play a big part in its healthful attributes, Provine adds.

Here’s why that matters: If you’re going to tell people they should laugh to improve their health, there may be a big difference between guffawing on your own without provocation, watching a funny YouTube clip or meeting up with friends who make you laugh, Provine says.

“That doesn’t mean the benefits aren’t real,” he adds. “But it may not be accurate to credit laughter alone with all these superpowers.”

But even for researchers like Provine who aren’t ready—at least not yet—to coronate laughter as a panacea, he doesn’t dispute the benefits associated with a hearty har har. He only questions science’s current understanding of the underlying mechanisms.

“When we laugh, we’re in a happy place,” he says. “That’s always a good thing.”

Read next: Is It Good Or Bad To Take A Nap?

TIME Exercise/Fitness

You Asked: Is Running on a Treadmill as Good as Running Outside?

runnig on a treadmill or outside
Illustration by Peter Oumanski for TIME

Nope—but it can come pretty close with one small tweak

To dedicated runners, running outside gets all the glory. Some purists even eschew headphones (and shoes!). But when talking about whether treadmill running is “the same” as running outdoors, it helps to pinpoint what sort of sameness matters to you.

In terms of the mechanics of your stride, there’s not much difference between running on a treadmill and running on ground, says Dr. Irene Davis, a professor of physical medicine and rehabilitation at Harvard Medical School who has studied the differences between treadmill and over-ground running. “While it feels much different to you, the leg motions and the forces experienced by your body are very similar between these conditions,” Davis says.

But when it comes to your risk for injuries, there may be an important difference. “Most running injuries are overloading injuries that involve muscle, cartilage, bone or tendons wearing down over time,” Davis explains. While there isn’t a lot of good research on this, Davis says those types of injuries probably occur more frequently when you repeat the exact same running motion thousands and thousands of times—as you would on a treadmill or a flat, consistent stretch of pavement.

“You strike the ground 1,000 times per foot, per mile,” she says. And if you’re running on a treadmill or a flat, hard surface, the redundancy of your motion increases your risk for these overuse injuries.

On the other hand, Davis suspects that changing up your stride has a beneficial effect on your injury risk. The more you move in response to curbs, corners, hills or leashed pets, the less likely you are to overburden the same muscle or tendon. Running courses that include lots of slopes, speed changes, and impediments—especially nature trails—are probably safest when it comes to your risk for wear and tear, she hypothesizes.

But what about the effort involved in running outdoors as opposed to on a treadmill? The big factor here is “air resistance,” which you’ll encounter more of outdoors than you will inside, finds a much-cited study from the University of Brighton in the UK. But there’s an easy fix for treadmill runners: By raising the grade of your belt very slightly—just 1% of added incline—you’ll mimic the effects of outdoor air resistance, the study authors conclude.

There may also be a psychological factor to the debate. Lots of research has found that time spent outside, especially in green spaces like woods or parks, offers benefits ranging from improved mood and energy levels to better sleep. And another UK study—this one from the universities of Exeter and Essex—found that runners who ran outdoors in natural environments reported greater feelings of revitalization and wellbeing, and decreases in tension, confusion, anger and depression. (Just don’t forget sun protection.)

All things considered, running outdoors and on trails makes the most sense for maximizing the benefits of running. But if the weather’s bad or a treadmill is your only option, don’t sweat it. It may be an inferior alternative, but only slightly so.

TIME Diet/Nutrition

You Asked: Is Eating Dessert Really That Bad For Me?

Illustration by Peter Oumanski for TIME

Mixed news on the dessert front, but there's a cherry on top

If you’re sampling sweets every night—and you aren’t super disciplined during the day—then yes, dessert is that bad for you.

Of course, there are different types of desserts. Dark chocolate, nuts, fruit and mishmashes of those ingredients generally aren’t a problem. Knock yourself out. But we’re talking about the oldies and goodies here: Cake. Ice Cream. Cookies.

“Combinations of sugar, white flour, butter and trans fat are diabetes on a plate,” says Dr. Walter Willett, chair of the department of nutrition at the Harvard School of Public Health. Studies have linked these ingredients to obesity and increased rates of type 2 diabetes. So if you’re eating dessert most nights, you’re asking for trouble, Willett says.

Of course, when it comes to anything diet related, there’s always a gray area. And for dessert lovers, that gray area exists if you’re very active during the day and you generally eat a diet low in added sugars, says Dr. Rachel Johnson, a professor of nutrition at the University of Vermont and chair of the American Heart Association’s (AHA) nutrition committee.

It’s important to clarify what Johnson means by “added sugars.” These are the sugars that don’t exist naturally in the foods you consume. For example, most dairy products and fruits contain sugar in the form of fructose and lactose. But when you buy a fruity drink or flavored yogurt, those natural sugars are supplemented with more of the sweet stuff. A lot more, in most cases. And those “added” sugars are the ones studies have tied to elevated blood pressure, out-of-control inflammation, abnormal blood lipids and heart disease, Johnson says.

The AHA says women should eat no more than six teaspoons—or about 100-calories’ worth—of added sugars per day. For men, that jumps to nine teaspoons or 150 calories, Johnson says. Most dessert foods contain that much sugar, or a whole lot more. And unless you’re making all of your own meals from scratch, you’re probably hitting or vastly exceeding that daily sugar allotment way before you reach for your evening ice cream. “Everything from ketchup and salad dressing to soups and bread will contain added sugars,” she says.

Johnson says super-active adults can eat a little more sugar without worrying. But even if you’re an exercise fiend, sugary dessert calories are still “empty” calories—meaning they’re not doing your health any favors even if they’re not hurting you.

Ok, you get it. Desserts aren’t good for you. (Surprise!) But if you love them and look forward to them all day, go ahead and have some, says Nyree Dardarian, director of the Center for Integrated Nutrition and Performance Coordination at Drexel University. “When you put rules and restrictions on something, you’re only going to want it more,” she says, which might be why recommendations to eat dessert just once a week or on special occasions often fail.

Instead of denying yourself the object of your affection—and thereby stoking its appeal—focus on portion control and breaking bad dessert habits, Dardarian says. You may be used to slicing pie generously or inhaling four or five cookies. But you’d probably feel just as satisfied having much less. “Don’t get in the habit of always having the same dessert,” or the same portion, she says. And don’t just eat out of habit: you may find there are nights when you’re not that interested in dessert.

And make it as cumbersome on yourself as possible to grab seconds, Dardarian recommends. If you put the cookies or cake back in its package and into the cupboard or fridge before you start eating, you’re a lot less likely to go back for more.

Johnson also recommends making your own desserts. The stuff you buy at the store is typically overloaded with sweet stuff (and chemicals.) But if you bake your own treats at home, you can substitute healthier oils, remove much of the sugar and toss in healthy additions like nuts.

“There are ways to satisfy your dessert craving in healthier ways,” Johnson says, “if you’re thoughtful about it and willing to put in a little effort.”

TIME Mental Health/Psychology

You Asked: Is Scaring Myself Healthy?

Illustration by Peter Oumanski for TIME

A little boo is good for you

For most people, a scare provides more treats than tricks.

When Michael Myers pops up behind Jamie Lee Curtis, your heart beats faster, your pupils dilate and your muscles tense in preparation for action, says Dr. Margee Kerr, a sociologist who studies fear and the ways it haunts our bodies and minds. This happens because fear floods your brain with “a powerful chemical punch” of fight-or-flight hormones and neurotransmitters, she says. Those include endorphins and dopamine—feel-good chemicals that dull pain, excite your mood and create an incredible natural high similar to falling in love (or doing some illicit drugs).

“Even though you knew you were never really in danger, you still feel a sense of euphoria after making it through a frightening event,” says Kerr, who also works with the design team of a haunted house in Pittsburgh called ScareHouse.

When you’re freaked out, your body also starts pumping out a bonding chemical called oxytocin—the same hormone that mothers produce during childbirth. This can make a frightful experience a fantastic way to solidify friendships and other social relationships. “Watch people walking out of a haunted house, and you’ll see lots of smiles and high fives,” Kerr says. Strong social connections have been linked to dozens of health benefits, including a longer life. And friends who are scared together, stay together, she adds. (Lovers, too, so pick the scary movie for a great date.)

There’s even some evidence that experiencing fear can bolster your ability to handle high-stress situations. Whether you’re watching a freaky flick or speaking in public, managing a knee-knocking ordeal builds self-assurance and acclimates your body to high-arousal states. “You become more comfortable with the physical experience of fear, and so you’re better able to work through it during tense situations,” she explains.

In fact, Kerr and colleagues at the University of Pittsburgh are hopeful that exposure to minor sources of fear—like seeing a horror film—could help those suffering from post traumatic stress disorder (PTSD) re-learn how to manage their fear responses in healthy ways. It’s just a hypothesis right now, but if a PTSD sufferer can engage with benign scary experiences and stay in control, he or she may become more comfortable with the deeper sources of their anxieties, she says.

But it’s important to note that not all people respond to freaky situations in healthy ways. “Everyone has a different tolerance level when it comes to fear,” Kerr says. What might be energizing or thrilling to one person might be debilitating to another. “Some people just shut down or are traumatized by their fear,” she adds. This can lead to nightmares, a prolonged inability to sleep, or unhealthy levels of anxiety.

“I worry when I see people being dragged into haunted houses or scary movies,” Kerr says. “They go along because of social pressure, but the type of fear they might experience can create some of these very negative consequences.”

Kerr also says children don’t respond to frightening situations in the healthy ways many adults do. “Kids who are younger than six or seven can’t separate real from make-believe, and seeing something frightening can be really traumatizing,” she explains.

But for many adults, a little scare now and then is a good, healthy way to experience some excitement. It’s just not for everyone. “People know what they enjoy and what they don’t when it comes to fear,” Kerr says. “What you find fun or thrilling, someone else may think is too much.”

TIME Research

You Asked: Is Cracking Your Knuckles Bad?

Illustration by Peter Oumanski for TIME

And just what is that cracking sound, anyway?

From fingers and toes to necks and knees, everyone knows a “cracker.” And most habitual joint poppers have heard rumors their habit may cause arthritis. But are those rumors true?

First, a quick anatomy lesson: Many of your joints—including those that allow your fingers to beckon or point—feature small pockets or gaps that are filled with synovial fluid. Like axle grease, this fluid allows the bones that commingle in your joints to glide close to one another without grating, explains Dr. Pedro Beredjiklian, chief of hand and wrist surgery at Philadelphia’s Rothman Institute.

When you pull, twist or otherwise “crack” a joint, you’re expanding the volume of space between your bones, Beredjiklian says. That volume expansion creates negative pressure, which sucks the synovial fluid into the newly created space. This sudden inflow of fluid is the popping you feel and hear when you crack a knuckle, he adds.

The more you crack your joint, the more you stretch and loosen both its capsule and the surrounding ligaments. And the looser those components become, the more easily your joint will pop, Beredjiklian says.

So is this bad for your joints? Almost certainly not, he assures. Multiple studies have looked into the prevalence of “crackers” among large groups of osteoarthritis patients. They found no evidence that finger pullers and poppers are more likely to suffer from arthritis than those who don’t crack their knuckles. One devoted researcher—a man who habitually cracked the joints on his left hand—actually studied himself. After roughly six decades of lopsided joint popping, this case study of one showed no increased presence of arthritis in his left hand as opposed to his right.

“Finger cracking is so common you would expect to see a lot of causal reports if it was harmful,” Beredjiklian says. “But you don’t. So I think it’s unlikely cracking joints in hands leads to arthritis.”

While one 1990 study linked long-term joint popping to hand swelling and lower grip strength, there isn’t any more research to back up that finding. On the other hand (pun intended), at least one study concluded that knuckle cracking offers those who do it a sense of almost therapeutic “release.”

Poppers, you can ignore your fusty aunt or cranky coworker when they try to scare you with talk of debilitating cracking-related ailments.

Just one note of caution: Tendons catching on irregular bone or joint formations can also explain some clicking or popping sounds, especially in places like your neck, Beredjiklian says. Whether this can cause harm will depend on the person and his or her anatomy. But if a weird sound emanates from your shoulder or knee when you flex it a certain way, you may want to avoid angering that area with deliberate cracking.

Read next: You Asked: Is Coffee Bad For You?

TIME Diet/Nutrition

You Asked: Do Fruit Flies Come From Inside Fruit?

Illustration by Peter Oumanski for TIME

You might not love this answer—but getting rid of them is easy.

Fruit fly moms lay their eggs on everything, from just-starting-to-ripen fruit—like the kind you recently brought home from the market—to the small bits of old produce rotting in your kitchen garbage can, according to the University of Michigan. Even some vegetables, particularly old potatoes and onions, foster fruit flies.

That’s gross. Fortunately, if your fruit isn’t overripe or rotting, the fruit fly larvae and their proud parents haven’t yet burrowed their way deep inside your apples or pears, explains Dr. Gregory Courtney, an entomologist at Iowa State University. They’re just hanging out around the surface of your produce, waiting for the juices inside to start fermenting. (If the risk of pesticides or dirt never inspired you to wash your fruit, maybe the possible presence of fruit fly eggs will do the trick: washing produce rinses away the eggs before they’ve hatched, as long as the fruit is ripe and fresh.)

When the eggs hatch, the babies tunnel into your old bananas and tomatoes and lap up the bacteria and yeast they need to grow big and strong—and to produce hundreds more like themselves. Adult fruit flies likewise feed on the byproducts of the fermentation process, which are also found in wine, soda and everything else you’ve noticed the little buggers hovering around.

In cozy indoor temperatures, the whole birth to reproduction cycle lasts only a couple of weeks, Courtney says.

These insects tend to show up in large numbers in late summer and early fall because it’s the harvest season, and America is filled with the fruits of the earth. With those fruits come fruit flies. And that’s a good thing, Courtney stresses. “They’re not disease spreading, they’re just annoying,” he says. Also, they’re one of many insects that feed on decomposing food. We’d all be neck deep in rotting banana peels and apple cores without them.

But even if you appreciate the bugs’ utility around the compost or trash heap, you probably don’t want them buzzing through your kitchen or lounging on the rim of your wine glass. To get rid of them, Courtney says the best defense is the most obvious: banish all but the freshest produce from your countertops. “Bananas seem to be a big culprit, but that may just be because there are always bananas in my house,” he says.

Buy produce only as you need it, and keep ripe or overripe fruits and vegetables in your refrigerator. Make sure there are no old food scraps hanging out on your floors, countertops or trash. Keep your kitchen free of all those sources for a few weeks, and you’ll wipe out your local fruit fly population, Courtney says.

If a few weeks seems like too long to wait, the University of Nebraska—Lincoln offers a more aggressive solution: Fill a jar with an inch or two of warm water, a teaspoon of yeast and a small amount of sugar to activate the yeast. Take a plastic sandwich baggie, poke a small hole in one corner of it using a sharpened pencil and stick that corner inside the top of the jar. Now secure the bag around the rim of the jar with a rubber band.

The yeasty water will attract fruit flies, which will creep down the bag and through the hole but won’t be able to get back out. Clean out the jar and start over once a week until the fruit flies are gone. Just don’t dump the jar’s old contents in the garbage. The water will likely harbor many fruit fly eggs, so it’s best to dump it away from your house. If you toss it down the sink, run your faucet for a full minute to ensure the eggs are washed away, the UNL report advises.

Or you could just live with your fruit fly friends. They’re pesky, but they serve a purpose.

TIME Mental Health/Psychology

You Asked: Is Meditation Really Worth It?

Illustration by Peter Oumanski for TIME

Totally. Here's why

Updated Oct. 9, 2pm

First of all, understand that “meditation” is a catchall term for a lot of different mental activities, many of which have nothing to do with sitting cross-legged on the floor and saying om.

“There are thousands of different types of meditation,” says Dr. Andrew Newberg, a neuroscientist at Thomas Jefferson University Hospital and author of Words Can Change Your Brain. But while meditative practices come in all shapes and styles, Newberg says nearly all of them have at least one thing in common: They involve focusing your attention, a habit that’s been marginalized by our smartphone-tethered lifestyle of digital distraction.

“That focusing could be on a word or object or physical motion,” Newberg explains. “But regardless, the type of focusing involved in meditation activates the brain’s frontal lobe, which is involved in concentration, planning, speech and other executive functions like problem solving.” Studies have shown meditation can bolster all of these mental tasks. But the greatest benefits may spring from the interplay between your brain’s focus centers and its limbic system—a set of structures that manage your emotions and regulate the release of stress and relaxation hormones.

MORE: The Mindful Revolution

“Studies suggests your body’s arousal system is calmed and the flow of stress-related hormones is reduced [by meditation],” Newberg explains. “There’s also a softening effect when it comes to emotional responses.” Just as weightlifting allows your muscles to lift a heavier load, working out your brain with meditation seems to fortify its ability to carry life’s emotional cargo. That stress-dampening effect has tied meditation to improved mood and lower rates of heart disease, insomnia and depression.

Newberg says there’s also some evidence that meditation quiets the area of your brain that manages your sense of self and your relationship to others. That may sound like a bad thing, but this quieting may help you feel more connected to others and less isolated within yourself, he says.

“Basically, meditation helps your brain get out of its own way,” adds Dr. Judson Brewer, a Yale School of Medicine psychiatrist.

Once you’re convinced meditation is worth a try, figuring out the right type for you is important, because the benefits tend to materialize only if you enjoy your practice enough to stick with it, Brewer says. Luckily, you have a lot of options—from Transcendental Meditation to Tai Chi. Even yoga counts, because it focuses your mind and blocks out distraction.

MORE: How Tai Chi Helps Fight Depression

Mindfulness is one style of meditation that’s exploding in popularity, largely because it can be done anywhere and anytime, Brewer says. “It’s mostly about being aware of your thoughts and not running after them in your mind,” he explains. Awareness is a wedge that, with practice, you can place between your thoughts and unhealthy emotional reactions, he says.

MORE: Can Yoga Ease Major Psychiatric Disorders?

That kind of vague, semi-abstract language can make meditation seem thorny and inaccessible, but it’s easier than you think. If you want a simple taste of meditation, Brewer suggests focusing your mind on your breath or a nearby object, refocusing it when it strays. “Your mind wanders, and you bring it back,” Newberg says. “That’s a mental push-up.”

Do enough mental push-ups, and you may be amazed at how strong your mind muscle can get.

TIME Research

You Asked: Is It Good or Bad to Take a Nap?

Illustration by Peter Oumanski for TIME

Snooze, or skip it?

You’re right to be confused. Even as a recent study linked napping to higher mortality, companies and colleges across the U.S. are installing nap rooms to boost productivity. Truly, it would be a dream to get some napping consensus.

But whether or not napping is right for you depends. “First of all, it’s important to ask yourself why you’re taking the nap,” says Dr. Sara Mednick, a psychologist at the University of California, Riverside and author of Take a Nap! Change Your Life. If you’re spending a big chunk of your day feeling sleepy and out of sorts, then your desire to snooze may be driven by stress, insomnia, sleep apnea or a hundred other slumber-disrupting health conditions, Mednick says.

“Daytime napping is an early indicator of underlying ill health,” adds Yue Leng, a University of Cambridge sleep researcher and coauthor of the study linking naps to higher mortality rates. Like Mednick, Leng suggests daytime drowsiness is likely a symptom of other health issues, not their cause.

Put simply, blaming naps for higher mortality rates is like blaming your doctor for heart disease; you’re more likely to see a doc if you have heart issues, but that doesn’t mean she’s to blame.

MORE: The Power of Sleep

Actually, naps are good for most people, Mednick says. Her research shows a nap—defined as daytime sleeping that lasts between 15 and 90 minutes—can improve brain functions ranging from memory to focus and creativity. “For some people, naps are as restorative as a whole night of sleep,” she adds. More research shows a quick nap can lower stress and recharge your willpower. And napping has also been linked to lower rates of cardiovascular disease and inflammation.

But all of these benefits depend on you getting a good night of sleep to begin with, Mednick stresses. Also, not everyone is a good napper. “Some people wake up from naps feeling like crap,” she says.

Genetics could explain why some people are nappers and some aren’t. But regardless of the explanation, there’s clearly a difference between the two groups. “People who aren’t habitual nappers tend to fall into very deep sleep during naps, and waking up from that leaves them feeling groggy,” Mednick explains. On the other hand, natural nappers—you know who you are—don’t plunge into deep slumber during their daytime snoozes, Mednick says. This allows them to wake up from naps feeling energized and alert, not discombobulated.

MORE: Pass The Pillow: “Google Naps” Is Google Maps for Places to Nap

For natural nappers, she says it’s “incredibly important” that you do catch your daytime ZZZs. “These people—and they probably account for about 40% of the population—tend to do really poorly if they don’t nap,” she explains. Without their much needed daytime shuteye, habitual nappers often reach for energy drinks, caffeine or other stimulants that perk them up but don’t recharge their cognitive batteries the way a short, healthy snooze would.

“For these people, skipping their nap is a huge productivity killer,” Mednick says, and that’s a compelling reason for employers and universities to provide nap spaces for employees and students.

While the length of an ideal siesta varies from person to person, 20 to 30 minutes is plenty for most. But up to 90 minutes—about the length of one full sleep cycle—could also be beneficial, Mednick says. She recommends trying different nap lengths to find the one that leaves you feeling the most refreshed.

If you’ve never been a napper but want to cash in on napping’s brain and health benefits, Mednick says you may be able to teach yourself to nap. The trick is to keep your daytime shuteye very short—no more than 15 minutes at first. This will prevent your brain and body from slipping into the deeper levels of slumber that leave you feeling foggy upon waking, she adds.

But if you’re just not a born napper, don’t sweat it. “Everyone’s different,” Mednick says. “If you feel good, whatever you’re doing is fine.”

TIME Aging

You Asked: Do Brain Games Really Improve Memory?

Illustration by Peter Oumanski for TIME

Unhand the crossword: it's not your golden ticket to a lifetime of quick wit and perfect recall

Games sure seem like a good way to work your brain out, but don’t put your stock in Sudoku. “They target very specific cognitive abilities, but they don’t transfer to clarity of thinking, problem solving, planning—all the complex skills that really matter,” explains Dr. Sandra Bond Chapman, chief director of the Center for Brain Health at the University of Texas at Dallas and author of Make Your Brain Smarter.

When it comes to keeping your brain real-world strong, research has shown–over and over again–two activities to be worth your time. The first is aerobic exercise, says Dr. Karen Li, head of Concordia University’s laboratory for adult development and cognitive aging.

By bolstering your cardiovascular fitness and blood circulation, exercise nourishes your brain with the nutrients and oxygen it needs to perform optimally, Li says. But physical activity offers more than just brain fuel. “Some brain regions and functions seem to benefit more than others,” she explains–specifically the frontal lobe, responsible for high-level skills related to complex processes like multitasking. “That tells us aerobic exercise helps the brain work more efficiently.”

Whether you enjoy running, speed walking, gardening or hiking, “as long as you sweat a bit and your heart rate goes up, that’s what your brain needs,” Li adds. Chapman agrees. “Skip the Sudoku and get out and exercise,” she says. (The Centers for Disease Control and Prevention recommends all adults get at least 150 minutes of moderate-intensity aerobic exercise a week.)

Along with physical activity, your brain needs mental stimulation to stay hale and fit. And when it comes to mental stimulation, novelty is important, Li explains. Here’s why: The more you use your mind to perform a task—whether it’s cooking your favorite dish or driving to the supermarket—the less effort your brain requires to complete that task. “If you feel like your brain’s on autopilot most or all of the time, that’s an indication that you need to increase the challenge a little bit,” she says.

One of the best ways to do that is to stay socially active, Li says. “Following and contributing to a conversation requires a lot of mental prowess.” Visiting intellectually invigorating places, like museums or cultural centers, and learning new skills are also great ways to keep your brain in shape. Even mixing in some variety when it comes to your favorite activities—like trying out a new recipe or cooking technique—will keep your mind off autopilot.

But there’s a catch. “It’s important that you feel genuine interest in these activities,” Li says. Practicing a foreign language for 30 minutes a day is a good way to challenge your brain, but if you feel meh about one day speaking fluent French, your mind won’t benefit as much as it would from something that truly excites or interests you.

If museum visits or learning new languages doesn’t float your boat, Chapman offers an alternate way to fire up your idling brain. “Challenge yourself to think in top-down, complex ways as you go about your day,” she recommends. When you watch a television show or read an article (like this one), pause once you’ve finished to really dissect the information you’ve just encountered. “Zoom out, then zoom in,” Chapman says. Start as broadly as you can (this is a health article) and work your way down (about the brain) until you’ve gotten to the nitty gritty—things like themes or lessons you could take away from what you’ve just seen or read (surely, too numerous to list).

“People take in a lot of information—probably more than we ever have before—but it’s not making us smarter because we’re not spending much time making sense of it,” Chapman says. “Try to push yourself out of your mental comfort zone by asking what about the information matters.”

This is especially important for older retired adults who aren’t faced with the everyday intellectual challenges presented by work or school. “We’re all going to be living longer,” Chapman says. “Along with aerobic exercise, engaging your brain in complex ways is absolutely necessary to keep your mind sharp in the second half of life.”

TIME Exercise/Fitness

You Asked: Should I Eat Before or After a Workout?

Illustration by Peter Oumanski for TIME

Experts answer the great exercise question of our time

Short answer: Both.

Long answer: How and when to fuel your body is the same for all exercisers to some extent, but your routine may warrant a few nutritional tweaks, says Dr. Nancy Cohen, head of the department of nutrition at the University of Massachusetts.

“In general, you’ll want to eat a meal high in carbs and protein and low in fat roughly three to four hours before you exercise,” Cohen says, whether you’re trying to shed pounds or build muscle. Carbohydrates supply your body with the glycogen it needs for your yoga session, gym visit, or jog. Skimp on carbs, and your muscles will sputter when called on to perform, she says.

If you’re trying to lose weight, it may seem weird and counterproductive to eat a carb-heavy meal before you hit the gym. But complex carbohydrates like beans, lentils, whole grains and starchy vegetables will provide exercise fuel plus nutrients and fiber. Unlike refined carbohydrates—things like white bread, cookies, soft drinks, or many pre-packaged foods—complex carbs won’t expand your personal equator or supercharge your appetite, research shows.

Cohen recommends avoiding fat in your pre-workout meal because it slows down your digestion. But eating protein supports your muscles. “During and after exercise, your muscle cells break down and rebuild,” Cohen explains. The right proteins contain the amino acids your muscles need to complete that cellular rebuilding process.

Complete protein packages include animal sources like chicken or lean beef, since they have all those amino acids, Cohen says. Grains like quinoa and bulgur as well as beans and some vegetables also contain protein, though probably not the “complete” kind. But if you eat a variety of those food sources, you can skip the meat and still get all the amino acids you need, she adds.

As for post-workout food, Cohen suggests eating or drinking more protein an hour or two after lifting weights for bodybuilders and athletes. But despite what you’ve heard, it’s not necessary (or healthy) to pound a massive protein shake the second you stop pumping iron.

According to Dr. Rob Danoff, an Aria Health System physician with a focus on sports medicine and nutrition, your body—and especially your kidneys—can only synthesize so much protein. Research suggests roughly one gram of protein per kilogram of body weight is plenty to maximize muscle growth. By that measure, for a person who weighs 175 pounds, 80 grams of protein all day is enough.

One large chicken breast or cut of red meat can contain 60 grams of protein or more, so slamming a huge protein shake after a workout will only inundate your kidneys with protein it can’t handle and your muscles don’t need, Danoff says. Apart from the risk of kidney damage, there’s evidence that overloading your body with protein can contribute to an imbalance in the acidity of your blood, which in the long run could lead to bone weakening. “It’s a myth that we need all this protein,” Danoff says. “More isn’t always better.”

In your workout-food focus, don’t forget water. If you exercise first thing in the morning, Cohen says dehydration is a big concern because you’ve probably passed much of the night without a sip of H2O. “Your whole cellular metabolism is dependent on fluid,” she says. And everything from your workout performance to your mood and mental acuity will suffer if you’re parched.

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