TIME Cancer

How Herpes Cells Are Being Used to Fight Cancer

Patients who used cells from this STD to treat their melanoma were 8 times more likely to survive than a control group

A genetically modified strain of herpes can kill cancer cells and stop tumors from growing, according to new research. The strain, called T-Vec, was used to treat patients with melanoma as part of one of the final phases of testing of a new drug.

The research, published in the Journal of Clinical Oncology, is the latest to show how viruses may be used clinically to kill cancer cells. Unlike chemotherapy, which casts a wide net and kills any proliferating cells, viruses often narrowly target cancer cells, which could make them more effective in fighting the disease. The method also appeals to researchers because it activates the immune system to fight cancer.

Researchers looked at more than 400 patients with aggressive malignant melanoma, the deadliest type of skin cancer. More than 16% of patients given the T-Vec treatment showed a lasting response for six months, compared with 2% of members of the control group given normal treatment.

“We may normally think of viruses as the enemies of mankind, but it’s their very ability to specifically infect and kill human cells that can make them such promising cancer treatments,” said professor Paul Workman, chief executive of the Institute of Cancer Research, in a statement.

The drug, produced by Amgen, now awaits approval from the U.S. Food and Drug Administration before it will be offered to patients.

 

TIME Research

You Asked: Are Self-Tanners Safe?

You Asked: Should I Use Spray Tanner?
Illustration by Peter Oumanski for TIME

These products are safer than sun exposure—but only if you avoid the sprays.

To bake, or to fake? It’s a classic tanning conundrum. Sitting under the sun causes skin damage and cellular changes that raise your risk for skin cancer, and even among adults under 40, melanoma rates are on the rise.

“In order to get a natural tan from ultraviolet light, your skin has to be injured,” says Dr. Darrell Rigel, a clinical professor of dermatology at New York University. You know this, and you worry about it. But unlike ultraviolet rays, sunless self-tanners don’t mean you have to damage your skin. “These products contain an ingredient that stains the outermost layer or your skin,” Rigel says.

In most cases, that ingredient is dihydroxyacetone (DHA). When it combines with amino acids in your skin, DHA causes a browning reaction—the same type of reaction that occurs when you make toast or grill meat, explains Dr. Adam Friedman, director of dermatologic research at Montefiore-Albert Einstein College of Medicine.

That may sound scary. But the browning only takes place in your skin’s “stratum corneum”—the topmost layer composed of dead cells, Friedman says. “Our bodies make a form of this stuff,” he adds, referring to DHA. “So I’m not concerned about it from as safety standpoint. When used topically, I think it’s the only safe way to have a tan appearance.”

For anyone who’s read up on self-tanners, Friedman’s statements may raise eyebrows. A few years ago, a much-cited report from ABC News raised concerns about spray-tanning salons and the risks of inhaling DHA and other self-tanning ingredients. Subsequent research supported the idea that inhaling spray-on tanning chemicals could potentially raise your risk for asthma, chronic obstructive pulmonary disease (COPD) or cancer.

“Stretched flat, your lungs are the size of a tennis court,” says Dr. Reynold Panettieri, a professor of pulmonary medicine at the University of Pennsylvania. “So inhaling these self-tanning agents could have all sorts of potential health consequences.”

But what about self-tanners you spread on your skin? The ABC News report cited Food & Drug Administration data suggesting that small amounts of DHA might seep through your skin and into your bloodstream. If true, that could also raise health concerns. But since that FDA data came to light, follow-up studies have failed to find evidence that DHA penetrates your skin’s protective barriers.

Dr. Rigel was one of several experts who voiced concern to ABC News following their DHA investigation. But when it comes to DHA in lotions, Rigel says his concerns have since been assuaged. “There’s no data to show that DHA is harmful when applied topically,” he says. “Pregnant women and children may want to avoid it just as a precaution, but this is benign stuff.”

Panettieri agrees. “Based on what we know today, DHA is really pretty safe when applied to the skin correctly,” he says. Correct application means avoiding the sensitive skin around your eyes and on your lips, as well as cuts or abrasions—more reasons to be wary of spray-on options. Panettieri says rubbing DHA into very thin or broken skin could let it enter your system. “Even if DHA got beyond the skin, any risk is hypothetical,” he’s quick to add.

Both he and Rigel say that compared to the well-established risks of sun exposure, topical self-tanning lotions are a safer option. Friedman agrees, and says his only concern is that some people might have an allergic reaction to DHA or other ingredients in self-tanners—a risk that comes with almost any cosmetic.

But Friedman adds one big warning: Self-tanners do not offer your skin any protection from sun damage. “Some people think these self-tanners act like sunscreen,” he says. “They don’t.” In fact, some research suggests DHA may actually increase the amount of damage your skin sustains from sun exposure.

Of course, new research could always surface new risks. And not as much is known about less-common tanning chemicals. But for now, if you’re craving a little color, self-tanning lotions with DHA seem to be your safest option.

TIME ebola

Did Authorities Use the Wrong Approach to Stop Ebola?

A health worker takes the temperature of a travelers at a highway checkpoint in Liberia on on Jan. 29, 2015.
John Moore—Getty Images A health worker takes the temperature of a travelers at a highway checkpoint in Liberia on on Jan. 29, 2015.

A new study suggests there was a better way to respond to the Ebola outbreak

It’s known that the response to the most recent Ebola outbreak, which as of Tuesday had infected more than 27,000 people and killed 11,130, was far too slow. Now, a new study suggests that even once they got started, their approach to curbing the spread wasn’t the most efficient or effective.

One of the staples of infectious disease outbreak responses was contact tracing: finding everyone who comes in direct contact with a sick person. And it makes sense that health authorities would employ that in this outbreak, since it’s proven in the past to be an effective way to contain the spread of a virus. However, experts at the New England Complex Systems Institute released new research Tuesday that argues contact tracing wasn’t the best approach.

Yaneer Bar-Yam, founding president of the Institute, and his colleagues conducted in-depth mathematical simulations that found that a community-wide response that monitors entire groups of people—rather than tracking down individuals who may or may not have been exposed to the virus via an infected person they had contact with—could have been more efficient.

In the simulations, the researchers accounted for a wide variety of factors and ultimately concluded that a response that focused on community-wide monitoring—for instance, going door-to-door to check on people in a given area as well implementing travel restrictions—would have been more effective than tracking down contacts of infected people one by one. The objective of a community response, they write, is to progressively limit the disease to smaller and smaller geographical areas, while simultaneously sending in resources.

“You treat the whole community as if it might have been in contact with someone,” says Bar-Yam. “Trying to figure out who [an infected person] was in contact with doesn’t make as much sense—and it’s not as cost effective as saying, ‘Well, everyone may have been in contact with these people, so we better check all of them.'”

One of the most telling parts of Bar-Yam’s study was when the researchers looked at what happens when people do not comply with the health guidelines that are put in place to curb an outbreak. After all, no matter how many times people are told what to do, it’s hard to persuade them to stay away from public areas, for instance, or to avoid travel to at-risk places. They found that community-wide monitoring is successful at ending the outbreak even if there’s only 40% compliance.

“You will save more lives if you have higher conformity,” says Bar-Yam of community monitoring, adding that, “from the macro picture you’re stopping the epidemic very rapidly.”

NECSI

The Key to Liberia Being Ebola Free?

In mid-September 2014 in Liberia, cases of Ebola started to drop significantly. It’s unclear why, but the authors note that around that time, a community-wide approach to stopping the spread of Ebola was taken in Liberia.

Earlier this month the Centers for Disease Control and Prevention (CDC) published a report on how it controlled the final cluster, and noted that the response included community-based approaches. And in a report on how Liberia got to zero cases, the WHO writes:

One of the first signs that the outbreak might be turned around appeared in September 2014, when cases in Lofa county, Ebola’s initial epicentre, began to decline after a peak of more than 150 cases a week in mid-August. Epidemiologists would later link that decline to a package of interventions, with community engagement playing a critical role.

In Lofa, staff from the WHO country office moved from village to village, challenging chiefs and religious leaders to take charge of the response. Community task forces were formed to create house-to-house awareness, report suspected cases, call health teams for support, and conduct contact tracing.

“I don’t know how difficult it would have been to implement it earlier,” says Bar-Yam. “Everyone kept saying, ‘Contact tracing is the tried-and-true right way to do this.'” Indeed, since contact tracing has been shown in numerous outbreaks in the past to be effective means of disease containment, that was the de facto strategy in west Africa during this Ebola outbreak.

This study alone cannot prove that health authorities and volunteers were misguided in their use of contact tracing.

Is It Either/Or?

The CDC declined to comment about the paper specifically, but spoke to TIME about the agency’s use of contact tracing and community monitoring. “When you are able to understand the connections [between people], while imperfect, you understand who is most likely to be infected and you are able to follow them,” says Jonathan Yoder, an epidemiologist with the CDC who responded to the Ebola outbreak in West Africa. “At the end, it was really important that nothing was missed. One contact can start a whole other outbreak. I don’t know that it’s one or the other. I think the approach of engaging communities is really important.”

Bar-Yam says his work shows that there is an alternative approach to contact tracing alone, and that it appears to work—possibly more quickly than contact tracing, if done early enough.

The paper also underlines the importance of being nimble when it comes to dealing with outbreaks of infectious diseases like Ebola. “Everyone thinks in terms of statistics of prior events. Everyone looks at prior history and says ‘What are we going to be able to expect in the future based on what happened in the past?’” says Bar-Yam.

TIME medicine

Newer Birth Control Pills Raise the Risk of Blood Clots

A new study puts a number on the risk of developing potentially fatal blood clots after using the pill

Blood clots have been a known risk of oral contraceptives since the 1990s, but for most women, the chances seemed small enough to justify taking the Pill. Now, in a report published in The BMJ, scientists led by Yana Vinogradova, a research fellow at the University of Nottingham, found that using the Pill was linked to anywhere from a two- to more than four-fold increased risk of developing clots compared to women who didn’t take oral contraceptives.

“Our study suggests that the newer contraceptives have a higher risk of [blood clots] than the older agents,” Vinogradova tells TIME in an email. Overall, the risk for women on the Pill was nearly three times that of women not taking the medication. The risk was highest for people taking Pills that contain newer types of the progestogen hormone, such as drospirenone, desogestrel, gestodene, and cyproterone, as compared to people taking the Pill with first-generation versions of the hormone (levonorgestrel and norethisterone).

The difference essentially boils down to the progesterone part of the drug; since the original pill was introduced in 1960, drug developers have tweaked the progesterone to lower side effects such as acne, headache, weight gain and breakthrough bleeding. But the price for those modifications may be more blood clots.

Even after Vinogradova and her team adjusted for the potential contributions of things like cancer, heart disease, varicose veins, arthritis, smoking and obesity on the risk of blood clots, the link between the newer contraceptives and increased risk remained strong.

“While [blood clots] are a relatively rare problem, they are serious and potentially avoidable with the appropriate drug choice,” says Vinogradova. “Doctors need to consider all health issues when prescribing contraceptives, selecting a drug type associated with the lowest risk for patients with particular susceptibilities.”

Whether that means that doctors should start with prescribing the older formulations first—as well non-hormonal birth control like the copper IUD—isn’t clear yet, since the newer forms have certain advantages, including the fact that they disturb the cholesterol system less, which may be important for diabetic women.

The blood clot risk, however, is something that doctors should consider when prescribing the Pill. And since there are different formulations available, Vinogradova says doctors should monitor their patients for any potential symptoms of poor circulation and switch to other formulations if needed.

TIME Research

Do LSD and Magic Mushrooms Have a Place In Medicine?

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Getty Images

Experts say it's hard to do research on the drugs under their current status

LSD and magic mushrooms are illegal for recreational use, but some medical experts see major benefits from the drugs. In a commentary published in the journal The BMJ on Tuesday, a London-based psychiatrist argues in favor of legally reclassifying the drugs so that they can more easily be used in medical research.

In his paper, James Rucker, a psychiatrist and honorary lecturer at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, argues that psychedelic drugs like LSD are less harmful and addictive than other controlled drugs like cocaine or heroin. But strict restrictions on the drugs make it difficult to conduct medical trials, he says.

Rucker writes that psychedelic drugs were frequently used in clinical research until they became classified as schedule 1 drugs—considered the most dangerous, and which aren’t used medically—in the UK in the late 1960s. “Hundreds of papers, involving tens of thousands of patients, presented evidence for their use as psychotherapeutic catalysts of mentally beneficial change in many psychiatric disorders, problems of personality development, recidivistic behavior, and existential anxiety,” Rucker writes.

It’s now challenging for researchers to conduct research on the drugs, largely due to stigma, cost and reluctance of funders to back such research. “These restrictions, and the accompanying bureaucracy, mean that the cost of clinical research using psychedelics is 5-10 times that of research into less restricted (but more harmful) drugs such as heroin—with no prospect that the benefits can be translated into wider medical practice,” argues Rucker.

Though Rucker is based in the UK, the United States has similar restrictions. According to the Atlantic, the world of research has in recent years seen a revival of interest in studying these drugs, but there’s currently no legislation to reclassify LSD and psilocybin, the main ingredient in magic mushrooms, for medical purposes.

Rucker says that in controlled settings like research laboratories, there’s little evidence to suggest that these can be harmful. But such drugs can be abused, and there’s some evidence to suggest that they can lead to health consequences that range from increased heart rate and nausea to memory loss among people who have abused the drugs for a long time.

“Importantly, and unlike most other drugs, the effects of hallucinogens are highly variable and unreliable, producing different effects in different people at different times,” the National Institutes of Health writes on its website. “Because of their unpredictable nature, the use of hallucinogens can be particularly dangerous.”

More research is needed to determine the safety and medical potential of psychedelic drugs —but in the UK, only four hospitals hold the expensive license necessary to conduct research on schedule 1 drugs, Rucker says.

TIME Hormel Foods

Hormel goes organic with latest big food acquisition

Hormel sliced turkey is seen for sale in Westminster
© Rick Wilking / Reuters—REUTERS Hormel sliced turkey

Deal is latest by big food company for a smaller 'natural' rival.

Hormel Foods is paying $775 million to buy organic processed meats maker Applegate Farms, the latest deal by a food giant for a smaller rival in the grocery aisle.

“A growing number of consumers are choosing natural and organic products,” said Hormel Foods Chief Executive Jeffrey Ettinger.

The deal will add Applegate’s deli meats, frozen burgers and dinner sausages to Hormel’s [fortune-stock symbol=”HRL”] portfolio of brands, which already includes Spam, Skippy peanut butter and the company’s namesake meats. The acquisition, which is expected to lift future profits, won’t add too much to Hormel’s sales. Applegate’s annual sales are expected to reach $340 million in 2015, a sliver of the roughly $9.3 billion Hormel records annually.

But the acquisition of Applegate is important for two key reasons. It is the latest deal by a “Big Food” maker for a smaller player. Smaller food makers have reported sharp sales growth as grocery shoppers at times turn away from legacy, established brands. Recent deals have included Hershey’s [fortune-stock symbol=”HSY”] acquisition of beef jerky maker Krave, Post Holdings’ [fortune-stock symbol=”POST”] deal for MOM brands, and Hormel’s own $450 million deal last year for Muscle Milk maker CytoSports.

Food companies are spending big on newer brands to lure consumers that want food they consider to be healthier. Applegate plays into the feel-good attitude that has been pervasive in the category. For example, Applegate says it produces meats that are “raised humanely without antibiotics and hormones.” The company’s webpage features an interview with CEO Stephen McDonnell talking about how he and other consumers want meats that don’t contain bad ingredients.

And like the Hershey deal for Krave, Hormel’s acquisition of Applegate is another big bet on protein. Industry analysts like NPD Group have flagged rising interest in protein, with studies showing nearly half of primary grocery shoppers have purchased protein-enriched foods and many are willing to pay more for those products.

Applegate will operate as a standalone subsidiary after the transaction is completed. The company has 100 employees, located primarily in Bridgewater, N.J.

TIME Heart Disease

How Much Alcohol Is Too Much? A New Study Has Answers

Alcohol, at least in moderation, can help the heart, but too much can be toxic. The latest study tells you where to draw the line

For decades, there’s been a steady line of literature welcomed by anyone who enjoys a regular drink or two: that moderate drinking can actually protect you from having a heart attack by keeping your vessels clear and relatively plaque-free. But there’s another set of data that shows too much alcohol can start to poison the heart. So where does the line between good-for-you and bad-for-you lie?

Researchers led by Dr. Scott Solomon, professor of medicine at Harvard Medical School and director of non-invasive cardiology at Brigham and Women’s Hospital, and his colleagues provide some clues Tuesday in their latest report in the journal Circulation: Cardiovascular Imaging. The scientists combed through data collected from 4,466 elderly people about their alcohol consumption. They also agreed to echocardiograms of their hearts. Solomon wanted to see if there were any changes in the structure of the heart that had anything to do with how much the volunteers reported they drank each week.

MORE: Should Alcohol Be Forced to List Calories?

The not-so-good news: The more the participants drank, the more likely they showed abnormal changes in their heart structure and function. In men, the changes started accumulating after more than two drinks per day, or 14 or more drinks a week. In these men, the pumping chambers of their hearts increased slightly compared to those in non drinkers, a sign that the heart had to work harder to pump the same amount of blood, which can cause it enlarge and weaken. In women, these changes appeared when women drank much less, just above the one drink a day. In addition, among the women who imbibed more than a drink a day, the scientists found slight drops in heart function compared to women who drank less.

“A little bit of alcohol may be beneficial, but too much is clearly going to be toxic,” says Solomon. “Once you get beyond two drinks a day in men, you get into the realm where you start to see subtle evidence of cardiotoxic effects on the heart that might over the long term lead to problems. And that threshold might be lower in women.”

The study provides valuable information about how alcohol affects the heart, and how much alcohol exposure can trigger changes to the heart’s structure and more importantly, how it functions. But where the tipping point lies with each individual between the benefits and harms of a having a few drinks isn’t clear yet. More studies investigating which genetic factors may predispose people, and in particular women, to the toxic effects of alcohol will need to done before more refined advice about how much is too much can be discussed.

Those investigations might start with potential differences in the way men and women process alcohol. The effects Solomon and his team saw remained strong even after they adjusted for body mass index, and other studies have hinted, for example, that the different hormone environments in men and women might be responsible for the increased vulnerability of women’s heart tissues to the toxic effects of alcohol.

Future work may also delve deeper into the question of how long people drink; like any exposure, the effects of alcohol may also be cumulative. Because the participants in the study were relatively elderly, with an average age of 76, their heart changes reflected decades of exposure to alcohol but it’s not clear whether there is a threshold for when the harmful effects dominate over the potentially beneficial ones.

“What is clear is that at more than two drinks a day is the point at which we start to think we are beyond the safe level for men, and with women, it’s likely to be even lower than that,” says Solomon.

TIME Diet/Nutrition

3 Delicious Ways to Get Creative With Your Veggies

sweet-potato-fries
Getty Images

Try homemade sweet potato fries

Bored with the same old salads and green juice? Time to get creative! Check out these fun ideas for falling in love with your vegetables all over again, from Candice Kumai, chef and author of the forthcoming book Clean Green Eats ($19; amazon.com).

Spiralize your squash

Get your pasta fix by putting yellow squash or zucchini into a spiralizer, then sautéing the “noodles” lightly in olive oil. “Just toss them with your favorite marinara and you’ve got a low-carb, high-fiber dish!” Kumai says. “If you’re still craving real pasta, you can do half and half.” Don’t have a spiralizer? Use a peeler to create squash “ribbons.”

Shave your sprouts

Cut Brussels sprouts in half, then carefully use a mandolin slicer to thinly shave them. “You can sauté them in oil and season, or drizzle on a homemade balsamic vinaigrette for a salad. I like to add blue Roquefort, walnuts and sliced pear for sweetness,” Kumai says.

“Fry” your sweet potatoes

You probably already order sweet potato fries at restaurants every chance you get. Why not make a healthy version at home? All you have to do is peel two medium sweet potatoes, then slice lengthwise. Lightly coat them in coconut oil and bake at 375°F for 40 minutes. Turn them halfway through.

This article originally appeared on Health.com.

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TIME global health

Man Dies of Rare Lassa Fever in New Jersey

He had recently returned from traveling in Liberia

A man died of a rare African virus in New Jersey Monday after recently returning from Liberia, officials confirmed.

The man died of Lassa fever, a virus that causes hemorrhagic symptoms but is very different from Ebola, the Centers for Disease Control and Prevention said. Lassa fever is only fatal for 1% of those who are infected, while Ebola can be fatal for 70% of those infected without treatment. Lassa fever is also much harder to spread from person to person (it’s usually picked up from rodent droppings). About 100,000 to 300,000 Lassa fever cases are reported in West Africa every year, resulting in about 5,000 deaths.

The man with Lassa fever had arrived at JFK airport from Liberia on May 17, and went to a hospital the following day complaining of fever, sore throat and tiredness, officials said. At that time, he did not say he had been traveling in West Africa, and he was sent home the same day. On May 21 his symptoms worsened and he returned to the hospital, at which point he was transferred to a facility equipped to deal with viral hemorrhagic fevers. The patient was in “appropriate isolation” when he died Monday evening. The CDC is working to compile a list of people who may have encountered the patient while he was sick, and they are monitoring close contacts for 21 days to see if they develop the virus.

TIME Diet/Nutrition

12 Reasons Why Dehydration Is Bad for Your Body

Being dehydrated can take a toll on your body and even your mind

It doesn’t take much to become dehydrated. Lose just 1.5% of the water in your body (the human body is usually about 60% H2O), and you’ve reached the tipping point of mild dehydration. It can be brought on by many things—and it can do much more to your body than just make you feel thirsty. Dehydration also brings on health effects ranging from fatigue and smelly breath to more dangerous consequences like distracted driving.

It gives you bad breath

It’s easy to forget to drink water during a busy workday, but at the end of the day you may find people standing unusually far from you when you open your mouth. “Dehydration can give you bad breath,” says Marshall Young, DDS, a dentist in Newport Beach, Calif. “Saliva has important antibacterial properties. When dehydrated, the decreased saliva in the mouth allows bacteria to thrive, resulting in bad breath.” So drink up for your own sake, and for those around you as well.

It makes you crave sugar

Dehydration can mask itself as hunger, particularly sugar cravings. This may happen particularly if you’ve been exercising, says Amy Goodson, RD, sports dietitian for the Dallas Cowboys. “When you exercise in a dehydrated state, you use glycogen (stored carbohydrate) at a faster rate, thus diminishing your stores more quickly.” So once you finish exercising, you will likely crave carbs to help you replenish those glycogen levels and get you ready for your next exercise bout.

It wrecks your workout

Even being slightly dehydrated affects your ability to put effort into your workout. “A 2% dehydration level in your body causes a 10% decrease in athletic performance,” says Goodson. “And the more dehydrated you become, the worse performance gets.” Measured by “perceived exertion,” how hard you feel you’re exercising, you might be working at a 6 but you feel like you are working at an 8, says Goodson.

It dries your skin out

Keeping skin healthy and glowing requires drinking enough water, says Anne Marie Tremain, MD, a dermatologist with Laser Skin Care Center Dermatology Associates in Long Beach, Calif. “It’s best to hydrate from the inside out,” she says. “Depending on your lifestyle you may need to adjust your water intake.” If you work out every day or are a caffeine fiend, for instance, then you’ll need to drink more., because workouts make you sweat and caffeine is a diuretic, which can dehydrate you. For smooth, moisturized skin, Dr. Tremain also suggests keeping showers short (less than five minutes) and using only lukewarm water as hot water can dry your skin out even more.

It may affect your ability to drive safely

Few things are more uncomfortable than being stuck in traffic or on a long drive when you need to use the restroom. Logically, it makes sense to simply not drink water before hitting the road. But new research published in Physiology and Behavior shows that the number of driving errors doubled during a two-hour drive when drivers were dehydrated versus hydrated—an effect similar to driving while drunk (defined by most states as .08% blood alcohol). Since often people purposely avoid drinking prior to a long road trip to prevent bathroom stops, dehydration could increase the risk of traffic accidents.

It makes you tired

A mid-afternoon slump may have more to do with hydration than you think. “When you’re dehydrated your blood pressure drops, heart rate increases, blood flow to the brain slows – all of which can make you tired,” says Luga Podesta, MD, sports medicine specialist at Kerlan-Jobe Orthopaedic Clinic in Los Angeles, Calif. A lack of water to muscles also makes physical tasks feel more difficult and tiring.

It sours your mood

Cranky much? Drink a glass of water and your mood may change. “Neurological effects of dehydration can cause irritability,” says Dr. Podesta. A small study published in the Journal of Nutrition tested mood and concentration in 25 young women who were either given enough fluids to remain properly hydrated, or who became mildly dehydrated by taking diuretics and exercising. The dehydrated women—who were at a level that was just 1% lower than optimal—reported headaches, loss of focus, and irritability.

It can give you the chills

It may seem counterintuitive, but dehydration can bring on chills. “This occurs because your body starts to limit blood flow to the skin,” says Dr. Podesta. In addition, water holds heat, so if you become hydrated it can be more difficult to regulate your body temperature, which can make you become chilled faster, even when you’re not in a cold environment.

It can cause muscle cramps

A lack of water causes less blood circulation, which can make muscles cramp up, says Ray Casciari, MD, medical director of the La Amistad Family Health Center in Orange, Calif. “The body will protect its vital organs, so it shifts fluid away from muscles and anything that’s not vital,” he says. Muscle cramps can be extremely painful, making muscles feel harder than normal to the touch. Changes in sodium and potassium through sweat loss can also contribute to cramping.

It makes you feel dizzy and foggy

Along with muscles, your brain also gets less blood circulation when you’re low on water, which can make you dizzy, says Dr. Casciari. Additionally, mild dehydration may affect your ability to take on mental tasks and cause you to feel foggy headed, according to a study from the British Journal of Nutrition. Interestingly, a study that appeared in the Journal of Nutrition showed greater mood changes in women than in men, both at rest and during exercise.

It can give you a headache

Dehydration can cause headaches in a couple of different ways. “Lack of water affects your body’s serotonin levels, which can give you headaches,” says Dr. Casciari. In addition, small blood vessels in the brain respond quickly to hydration levels (which is also behind hangover headaches), leading to dull aches and even full-blown migraines. Try downing a glass or two of water the next time you have a headache and you may discover it disappears. You could also eat fruit, which contains a high percentage of water, Dr. Casciari suggests.

It constipates you

Your body needs water to keep things moving through your colon. When you’re not getting enough H2O, your body compensates by withdrawing more fluid from stool, making it harder and more difficult to pass. That said, it’s worth noting that drinking more water when you’re already properly hydrated won’t necessarily relieve constipation caused by other factors, like the medications you’re taking, medical conditions, or a lack of fiber in your diet.

This article originally appeared on Health.com.

Read next: 12 Mental Tricks to Beat Cravings and Lose Weight

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