Science

the “digestion cut” does not exist and science is clear why

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There are some very ‘mother’ phrases that are very well ingrained in our minds and without a doubt one of them is the obligation to wait strictly two hours after eating before entering the pool or the beach. Under the pretext of ‘digestion cut‘, there are many children (and also adults) who have to wait before taking a dip for fear of drowning. However, this is a myth. A popular fable. The concept of “digestion cut” It is not something that is included in the different medical guides nor is it categorized by the WHO as an existing disease. And this is what specialist societies such as the Spanish Society of Primary Care Physicians also point out, whose expert Ángel Jimeno Aranda clearly points out that cutting digestion is a popular term: It really has nothing to do with digestion, although it is true that when you feel so bad after suddenly entering cold water, you begin to have a headache, blurred vision, fatigue, nausea, vomiting or abdominal pain. The symptoms have caused this popular belief that the problem has a digestive origin, but it has nothing to do with digestion. It is more of a vascular process What really happens. If the ‘digestion cut’ does not exist, then… What happens? The answer lies in immersion syndrome, also technically called hydrocution or thermodifferential shock. This phenomenon is triggered when there is a large temperature difference between a bather’s skin and the water, usually when the latter is below 27°C or there is a thermal difference equal to or greater than 5 °C with respect to body temperature. In the body, This is instantly detected by the different receptors that begin to send signals to the brain to provoke an uncontrolled automatic response characterized by involuntary reflex inspiration, hyperventilation and severe cardiac arrhythmias that can lead to immediate drowning, regardless of the state of digestion. So, as we see, it is a completely vascular problem and has nothing to do with having had a sandwich just before going to the restaurant. Matches the food. Despite being a myth, the historical relationship between eating and immersion syncope has a hemodynamic explanation, since during the time after eating, the body redistributes blood flow to the areas that need it most, which at that time is the stomach to be able to digest. This means that there is not as much blood in other parts of the body. In this way, if a person is suddenly immersed in cold water in the middle of the digestive process, and especially if they have been in the sun, the body executes massive peripheral vasoconstriction to contain the heat in the body. Literally, there is a clash between the stomach’s demand for blood and this constricting response, which generates a conflict of signals for our brain, which does not know who to give priority to. The result It is nothing more than hyperstimulation of the vagus nerve that produces a drop in heart rate and also blood pressure. And lowering pressure is not good news because it generates cerebral hypoperfusion, resulting in dizziness, nausea, loss of vision and, in the worst case, syncope. The reality. With all this data it has become quite clear that waiting 2 clock hours after eating to bathe is false, since the determining factor is not the time, but the method of entering the water and the temperature difference. If we look at it from another perspective, if we talk about warm water, this is something almost impossible to happen, even if we have just eaten. The recommendations The steps to follow focus on entering the water slowly, allowing the skin receptors to acclimatize to the temperature to which we are exposing them, first wetting the extremities, the back of the neck and the abdomen. In addition, sudden changes must be avoided after physical exercise or sunstroke, since the body temperature here will be very high and can be a problem regardless of whether the stomach is full or empty. Images | Callum Hill In Xataka | It is increasingly common to find jellyfish on Mediterranean beaches before summer. And it’s a bad sign

What science says about mixing CrossFit, Hyrox and running to get you ‘clubs’

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Traditional weight rooms are changing, and where previously routines divided by muscle groups and the atrocious fear of doing cardio because it “destroys the muscle” reigned, today we have a hybrid training that aims to prevail among all gym lovers. New trend. Disciplines like CrossFitthe explosion of events like Hyrox and the fashion of combining heavy weight lifting with running They have created the figure of the total athlete who leaves nothing aside. But, beyond the marketing that this sports strategy may have, what really happens to our body when we try to be the strongest and the fastest at the same time? A myth. For years, a thought that has been on the minds of many athletes is that running has an “interference effect” with their bodybuilding routines. The reasoning here was that resistance training such as cardio sent molecular signals opposite to strength training, limiting muscle hypertrophy, which is what is sought in the gym. But now there are many nuances about it. For example, an analysis published in 2024 analyzed 59 studies with more than 1,300 participants and pointed out that in women, combining strength and cardio does not produce any interference significant in leg strength. In the case of men, there is a small interference in the development of lower body strength when mixing both modalities, but minimal. That is, it does not justify leaving it aside if we want to improve our health as a priority over hypertrophy. What is the best training? As we have mentioned, hybrid training groups traditional strength exercises with cardiovascular training, such as running on a treadmill. But the reality is that there are many options available, such as Hyrox or CrossFit, and each one has its own peculiarities. Hyrox. A hybrid training that combines 8 kilometers of running interspersed with 8 bodybuilding routines and is often defined as the definitive hybrid test. But here a study from 2025 pointed out that the aerobic factor is the undisputed kingthat is, Hyrox considerably increases people’s aerobic capacity and this is essential to determine the quality of life in old age, since, in addition to cardiorespiratory improvement, it also makes oxidative metabolism more efficient and muscular endurance. Contrary to what many believe when seeing heavy sleds, maximum strength is not a key predictor of success in this competition, but rather it is a systems sport where the entire body is mobilized and makes our cardiovascular system play a leading role. CrossFit. This presents a better metabolic profile, since, by addressing 10 different physical domains, it is postulated as a more complete but less specialized discipline. Here the science indicates that CrossFit dramatically improves cardiorespiratory fitnessoxidative metabolism and muscle resistance. But in addition to all this, it also stands out for the high levels of motivation and adherence thanks to the community component that it has associated. How to do it. If we want to join the hybrid fever, how do we prevent cardio from eating into our strength gains? Here the key seems not to be in stopping training, but in programming each of the steps we take in the gym, since the interference depends directly on the modality, frequency and duration of aerobic exercise. For example, running interferes much more with leg strength than cycling, due to the eccentric muscle damage caused by the stride. One of the most important points here is that, if we want to improve strength over cardiovascular endurance, the best always is to do strength exercises first before starting to run on a treadmill in order to have greater strength gains. When to start. If you want to join this combined exercise fever, the reality is that there is nothing that can stop a person as long as they do not have an injury or a doctor’s recommendation not to do high-intensity exercise. It is true that on the first occasions it may be interesting to go to a personal trainer or a gym where they also have specialists who can develop the best hybrid training plan. And, although this modality is not going to take us to a bodybuilding platform, it does prepare our body for any situation and above all for a much higher quality old age. Images | Alora Griffiths In Xataka | The 11 best apps for exercising at home

that’s why it’s back to science fiction

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Steven Spielberg has been using science fiction for almost fifty years as a reflection of the concerns of American fears (that is, planetary, because pop culture works the way it does). In 1977 he captured the post-Vietnam spiritual void with aliens coming in peace. In 2005, he processed 9/11 with aggressive invaders. ‘The Day of Revelation’ has some ingredients similar to all of them, although perhaps for the first time in his career, reality has gotten ahead of him. The constant. Of the 37 films Steven Spielberg has directed, about a quarter are fantasy or, more specifically, science fiction. And of them, six include aliens in their plots. Let’s review some of the most relevant ones: Encounters in the third phase (1977): Two years after the end of the Vietnam War. The United States saw the moral authority of its institutions plummet. Spielberg gave the public some hope with a film in which contact with the unknown did not end in war but in amazement: the aliens came in peace and the protagonist followed them into space. Decades later, the Library of Congress included the film in its archives as being “culturally, historically and aesthetically significant.” ET the exterrestrial (1982): In the midst of the Reagan era, political discourse insisted on rebuilding the nuclear family as a central value of society. Spielberg put a broken family at the center of his film, with a mother raising her children alone after a divorce, and offered as reparation for domestic trauma the most unlikely friendship: a child and an alien. ‘ET’ claimed that solutions had to be found to heal a fractured society. As Spielberg himself has said, “My favorite science fiction is based on terrestrial problems”. ‘War of the worlds’ (2005): Spielberg once said of the 9/11 attacks that “the image that I can’t get out of my head It is that of all the people of Manhattan fleeing over the George Washington Bridge.” It is perfectly perceived in a film that is pure panic, nothing rooted in a specific policy, since as screenwriter David Koepp said in his day, it also functioned as an allegory of Iraqi fear of an American invasion. Koepp also signed ‘Jurassic Park’, the film that showed us the only good billionaire, and now he returns with ‘The Day of Revelation’. And even if it is outside the topic of invasions and dealing with social aspects that are not so clearly politicized, it is inevitable to remember science fiction films like ‘AI, Artificial Intelligence’where many first discovered the fashion acronym; ‘Minority Reportas a bridge between the paranoia of the fifties and the era of hypervigilance we live in now; and in a more (sadly) banal tone, ‘Ready Player One’about The Video Game and its implications. The secrets are over. In December 2017, The New York Times published a report about AATIP, the Pentagon’s secret program to investigate anomalous aerial phenomena with a budget of 22 million dollars. The report described objects that moved in ways that defied known engineering. That journalistic piece, according to Spielberg, restored his interest in the alien topic. In the summer of 2023 he spent two months writing a 50-60 page synopsis of what would happen the day that information became public. The project was officially announced in April 2024. The year when reality did not waitOn May 8, 2026, five weeks before the premiere of ‘Revelation Day’, the Trump administration ordered the publication of the first 162 declassified files on UAPsincluding diplomatic cables, FBI reports, NASA transcripts and graphic material, all accessible without prior authorization on the war.gov/UFO portal. On May 22, a second delivery arrived with six PDF files, seven audios and 51 videos. The portal intends to continue expanding. When NASA was worried. Spielberg himself has acknowledged that those congressional hearings “changed everything” for him and that “this stopped being sensationalism and became something that the mainstream media took very seriously.” In this way, ‘The Day of Revelation’ continues to be a social thermometer, although now it does so perhaps at the opposite pole to ‘Close Encounters of the Third Kind’, once the debate has been institutionalized. In fact, while preparing ‘Close Encounters…’ in the 1970s, Spielberg received a letter from NASA asking him not to make the film. “When I found out that the government was opposed to the film, I found my faith”declared in 1978: “If NASA took the time to write me a twenty-page letter, something was up.” It cannot be said that the Spielberg of today raises the same suspicions as the one from then, and perhaps his new film should be read under that code. In Xataka | When Spielberg heard one of the best soundtracks in history, he didn’t get it: “I thought it was a joke”

We thought that the problem of insomnia was on the mobile screen. Science points to the harmless five o’clock coffee

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There is a ritual that many of us follow without questioning it. We arrived at five in the afternoon with our brains fried, we ordered a coffee—or a tea, or a Coca-Cola—and we continued. It’s the push we need to get through the rest of the day. What almost no one knows is that that five o’clock coffee may be sabotaging your eleven o’clock sleep. What we usually do when we don’t sleep well is point to our cell phone, stress, late dinner, or looping thoughts. We rarely point to the cup. And yet, for doctor Pablo Ferrero, a specialist in sleep medicine, the answer is there: “Caffeine is the number one enemy of good rest.” The chemistry behind the problem. To understand why caffeine is so disruptive, you have to know adenosine. It is a substance that the brain accumulates during waking hours and that, when it reaches a certain level, gives us that feeling of tiredness, that it is time to stop. It is, in a certain sense, the biological alarm of sleep. What caffeine does is to block adenosine receptors: Silences the alarm without disabling actual fatigue. The body continues to accumulate fatigue, but the brain stops perceiving it. The problem is not just that it is difficult to fall asleep. It’s what happens inside while we sleep. A study published in the Journal of Clinical Sleep Medicine found that a dose of 400 milligrams of caffeine consumed six hours before bedtime significantly reduced sleep efficiency. Other job in Neuropsychopharmacology was more specific: Consuming caffeine before bed reduces the amount of REM sleep, the phase in which the brain consolidates memories and regulates mood. More in depth. The numbers They are concrete and not very reassuring.: That dose can delay sleep onset by up to 45 minutes and reduce deep sleep—NREM phases 3 and 4—by up to 20%. Taken to everyday practice: if you have a coffee at 5:00 p.m. and go to bed at 11:00 p.m., your deep sleep can go from the usual 120 minutes to just 96. That’s 24 minutes less brain and physical repair. Nightly. But there is something even more disturbing: a scientific review published in the magazine Nutrients concluded that caffeine can reduce deep sleep even when the person sleeps eight hours continuously. That is, it is not enough to add hours. Quality does not always coincide with the perception of having a good rest. You can wake up thinking you’ve had a great night’s sleep while your brain hasn’t gone through the cycles it needed. Time matters. One of the most common mistakes is to think that afternoon coffee “no longer works” because you are used to it. Tolerance reduces the perception of the stimulus, but The half-life of caffeine in the body is between 4 and 9 hours: That means that half of what you drank at three in the afternoon is still active at eleven at night. And the problem is not limited to coffee. Caffeine is also present in some soft drinks, energy drinks, teas and chocolates, something that Ferrero expressly points out as a factor that goes unnoticed. It’s not just the breakfast cup: it’s the entire consumption circuit of the day. The broken clock. Caffeine, however, does not act alone. Ferrero points to another factor that can be even more decisive: schedule disorder. The body works through the circadian rhythman internal biological clock that regulates when we feel sleepy and when we are alert. When schedules constantly change—we go to bed at eleven Monday through Thursday and one o’clock on Fridays and Saturdays, and we get up three hours later on Sunday—that system loses synchronization. science back this up with data: Sleeping at irregular hours can cause insomnia, daytime sleepiness and alter hormone production, metabolism and eating habits, increasing the risk of diseases such as diabetes, obesity and depression. The impact don’t stop feeling tired Since while we sleep, the brain eliminates the beta-amyloid protein, accumulated during wakefulness and directly related to Alzheimer’s and other neurological disorders. Poor sleep is not just a tomorrow’s problem: it is a long-term investment—or debt. The motive is not innocent either. But the mechanism is more precise than is usually explained. The blue light emitted by screens suppresses the production of melatonin, the hormone that signals the brain it’s time to sleep. A study by the Barcelona Institute for Global Health warned that this overexposure directly alters the sleep-wake cycle. Just two hours of exposure to bright screens before bed can reduce melatonin levels by 20% or moreand the time to fall asleep can go from 15 minutes to more than an hour. Using a tablet before going to sleep can delay nighttime sleep by up to 96 minutes; that of a smartphone, up to 67. Harvard Medical School noted that “just a few minutes of screen stimulation can delay the release of melatonin by several hours and desynchronize the biological clock.” The problem is that we live in a society with increasingly irregular patterns: high light exposure at night, changing work schedules, screens until the last minute. We are sending our brain signals that it is still daytime when it is no longer daytime. So what works? Ferrero’s answer is not particularly glamorous, but it is supported by evidence. Going to bed and getting up at similar times every day—even on weekends—is the most basic and most ignored advice. Added to this is a dark, quiet and cool bedroom: artificial light and high temperatures send alert signals to the brain that make it difficult to rest. Avoid screens before going to bed—at least 30 minutes—and have a light dinner, without excess fats or spicy food, close to bedtime. For those who do not have insomnia, a short nap may be beneficial; The key is that it does not exceed 25 minutes so as not to disturb your night’s sleep. And in the face of anxiety or thoughts in a loop, Ferrero points out tools with scientific evidence: … Read more

We have turned probiotics into the miracle pill of the 21st century. Science has something to say about it

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They are in pharmacies, along with vitamins C and multivitamin complexes. They are on the shelves of organic supermarkets, between adaptogens and turmeric shots. They occupy the reels of TikTok with the same enthusiasm with which before detox juices populated. Probiotics – supplements with live microorganisms that supposedly strengthen the intestinal flora – have become the health amulet of the 21st century. The promise is simple and seductive: take these “good” bacteria in a capsule and your gut, your brain, your immune system, and your skin will function better. The business accompanies the promise. According to different estimates from the sectorthe global probiotics market was valued at around $114 billion in 2025 and is projected to continue growing at a sustained rate over the next decade. However, there is a problem that science has been contemplating for years: taken massively and indiscriminately, probiotic supplements not only do not improve the microbiome in the majority of healthy people. In some cases, they can actively block it. A forgotten organ that regulates almost everything. The human intestine is home to trillions of microorganisms—bacteria, fungi, viruses—that form an ecosystem as complex and personal as a fingerprint. According to gastroenterologist Chris Dammanfrom the University of Washington, who has been studying the microbiome for 20 years, this ecosystem acts as “the gateway to the body’s overall health.” Diets with more fiber, fruit and vegetables are those that generate the greatest variety and richness of bacteria in the intestine, and healthy bacteria produce short-chain fatty acids that support the health of the intestinal lining, according to the clinical documents of the Whole Health from the US Veterans Administration. The microbiota is not just digestion. A review published in the journal Nutrients by researchers at the University of Cassino in Italy, details how the gut microbiota modulates neurochemical pathways involving serotonin, dopamine, GABA and glutamate, as well as the immune and endocrine axes. Microbial imbalance—what scientists call dysbiosis—contributes to low-grade systemic inflammation, impaired neuroplasticity, and altered stress responses, all of which are linked to mood disorders and cognitive decline. However, the most striking fact is that Approximately 95% of the body’s serotonin is synthesized in the intestinenot in the brain. Whether the intestine is good or bad is no small matter. Take care of the microbiota is key to healthbut to make good use of probiotics it is important to first understand their real mechanism. And that’s where things get complicated. Years of warning. The problem with probiotics is not that they never work. The thing is that we have turned them into a general use resource, something that is taken preventively and continuously, without diagnosis, without medical indication and without understanding what is really happening in each person’s intestine. A product with real and very specific benefits that social networks have turned into a universal solution. Dammam explains it clearly: Probiotic supplements purchased without a prescription are not sufficiently regulated. You don’t really know what you’re taking. Products vary greatly in labeling accuracy, presence of adulterants, and legitimacy of their claims, according to VA Program documents. Prescribing probiotics is difficult even for doctors: there are thousands of products on the market, each claiming superiority over the other. Many have “special recipes,” proprietary strains or combinations of multiple organisms that the VA wryly describes as “a microbiological shotgun approach.” The problem, ultimately, is not just the lack of regulation. It’s that we start from a wrong premise. The science behind. Dr. De la Puerta, an expert in microbiota, sums it up with a phrase that does not leave much room for interpretation: “If you want a healthy microbiota, you probably don’t need to live taking probiotics.” He said it in podcast by Dr. José Abellán in one of the most shared analyzes of intestinal health in recent weeks. Her central argument is not that probiotics are useless—in fact, she herself admits that she uses and prescribes them frequently—but that they are becoming a permanent habit when they are designed to be a one-time tool. “You have to take them to get you out of a place,” he explains. And he gives his own case as an example: “My microbiota is fairly good, but I have a lot of stress. So I take probiotics from time to time.” The key is in those two words: seasons. Deeper investigations. The latest science backs up exactly this nuance. A review published in Trends in Microbiology concludes that the composition of the microbiome varies greatly depending on geography, age and lifestyle, which directly calls into question the efficacy of universal probiotic treatments and requires that the design of any effective probiotic takes into account microbial diversity and specific adaptation to the context of each host. The Probiota 2025 conference, held in Copenhagen, confirmed this same idea: Geographic and demographic variations reveal microbiome profiles so different among healthy populations that it is impossible to define a universal standard of a “healthy microbiome.” There is another equally serious problem, which Dr. De la Puerta points out precisely: not all probiotics are the same, even if we sell them as if they were. “Take a probiotic, stabilizer, immunomodulator, neuroactive, high load, low load, monostrain, multistrain…”, he lists. Some have more to do with the immune system, others with digestive health, others with mood. The most successful interventions are those informed by a microbial profile prior to treatment, which allows predicting therapeutic efficacy. “That’s why it doesn’t make much sense to buy them at random simply because someone has recommended them on social networks,” the expert details. The garden already planted. There is a conceptual error that lies at the bottom of this entire debate. We take probiotics as if the intestine were empty land waiting to be repopulated. But in the vast majority of healthy adults, the intestinal ecosystem is already established and has its own defenses. According to the VA Programcontinuing to take them once a healthy intestinal ecosystem is formed would be like planting an already planted garden. The real problem, … Read more

We have believed all our lives that “dying of grief” was a romantic myth. Science is clear that there is some truth

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The classic scene of two old people who have been together their entire lives, and when one dies, the other follows him a few days later because “he couldn’t bear the pain” seems to be something that remains in the movies. However, what we have always dismissed as romantic hyperbole or statistical coincidence has, in reality, deep physiological support. It is studied. A recent deluge of scientific data puts on the table a conclusion that is quite devastating by pointing out that intense grief not only hurts emotionally, but also drastically increases the chances of suffering a fatal cardiovascular event that triggers long-term mortality. The most robust and recent confirmation comes through a study published in Frontiers in Public Health that analyzed 1735 people in a ground situation to be able to find out what happened in the long term with those who could not overcome a loss naturally. The results. The researchers here divided the patients into groups according to the intensity and duration of their suffering. What was precisely seen is that those who showed a high and sustained grief trajectory, which is called prolonged grief, not only needed many medical consultations and psychotropic drugs, but also presented a higher risk of mortality than the low grief groups. Translated into plain numbers: people trapped in persistent grief were almost twice as likely to die in the decade after the loss. The heart breaks. When we receive bad news, we sometimes say that the heart ‘has broken’ and for many it may seem strange, since physically the heart is intact. But this expression, which may be popular, has clinical demonstration behind it, as pointed out a published study in Circulation which shows that the first weeks after widowhood or the loss of a loved one are high risk. Specifically, in the first 24 hours after the loss, it was shown that the risk of suffering an acute myocardial infarction reached its maximum peakwhile in the following 30 days cardiovascular events also increased, including stroke. In the guides. As a curiosity, there is even a clinically documented pathology known as Takotsubo syndrome (or broken heart syndrome), which is a cardiomyopathy induced by extreme emotional stress that temporarily weakens the heart muscle, simulating the symptoms of a massive heart attack. The small print. What has been compiled in this case is a statistical correlation, that is, that those people who have had a deep mourning have seen their mortality increase. But this does not mean that there will be an event of this magnitude. What happens in these cases is that grief is a marker of constant vulnerability, since cortisol levels increase, keeping the body in a state of alert that exhausts the immune system. But in addition, those who suffer extreme grief often stop eating properly and reduce their physical activity to zero, and in many cases, forget to take their medication. All of this ultimately increases the risk of mortality, but not the loss itself. Images | Yosi Prihantoro In Xataka | More and more people die from a sudden heart attack in Spain: the sudden death pandemic

The human being is the primate that sleeps the least. Science is clear that it is a “radical evolutionary experiment”

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We spend a third of our lives sleeping, yet the most common complaint in modern society It’s the lack of rest. We tend to blame screens, work stress and artificial light for robbing us of hours of sleep, but here evolutionary anthropology has a much more forceful answer: human beings are genetically designed to sleep less than any other evolutionary relative. It is studied. It is not something that we see from afar as a mere hypothesis, but researcher David R. Samson, professor of Evolutionary Anthropology, recently published a book that includes the results of his research. And the truth is that, after living with hunter-gatherer tribes like the Hadza in Tanzania and the BaYaka in the Congo, their conclusion is resounding: humans are an absolute biological anomaly. We are the great early riser. If we take out the calculator and the meter, a primate more or less of our same average body mass, brain size and diet should sleep about 9.5 hours a day. But this figure is limited to a fairly select few people, since we actually sleep around 2.5 hours less than our evolutionary biology predicts, making us the primates that sleep the least of all. This is a pretty clear conclusion. if we compare ourselves with other species that have very high sleep rates, as can be seen in the following list: Chimpanzee: between 9.5-11.5 hours a day. Gorilla: 10-12 hours. Pig-tailed macaque: 14 hours. Night monkey: 17 hours. Because? How is it possible that with the most complex and energetically demanding brain in the animal kingdom we sleep so little? The answer seems to lie in the “deep sleep” hypothesiswhich suggests that evolution forced us to have a much deeper and more efficient sleep to sleep much less than the rest of the hominids. For example, humans spend approximately 25% of our rest time in the REM phase, which contrasts with species such as African green monkeys, which They only dedicate 5% to this phase. But in addition, human sleep has a lower proportion of light sleep, since in return, it has a higher proportion of deep sleep. A necessity. Having a much shorter rest was not a whim of ours, but rather a matter of survival, since by leaving the safety of the trees, where our ancestors slept safely, and descending to dry land, the risk of predation skyrocketed. Regarding shorter sleep, evolution promoted several mechanisms to guarantee our survival, such as sleeping next to the fire and in large groups for greater security. But in 2017 a study showed that natural variation in chronotype allowed someone to always be awake standing guard during the night. Don’t blame the screens. It is tempting to think that we sleep for about 7 hours because electric lights and smartphones have altered us in this modern life. But this is not the case, because after analyzing the sleep of the Hadza, who are a hunting community in Tanzania without access to electricity or mobile phones, it was shown that their patterns are identical to ours, sleeping 6.25 hours a night and maintaining a sleep efficiency of 68.9%. Images | MediaEcke In Xataka | We’ve been sold melatonin as the ultimate harmless sleep supplement. Science does not think the same

93% of owners believe that sleeping with their dog improves their rest. Science has just proven that it is self-deception

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Night comes, you get into bed and, almost out of inertia, your dog or cat jumps on the mattress to curl up at your feet. For many people, pets are full members of the family and even share the sheets. According to a report from the platform Sleep Foundation56% of people say they sleep with a pet in their room. The bond is so strong that the mere idea of ​​changing this habit generates rejection. Sleep psychologist Shelby Harris recounts in an interview for The New York Times that when caring for patients with insomnia problems, the first reaction is usually almost defensive: “I have a dog. You’re going to tell me not to sleep with him.” And, although sleeping with our animals gives us an immense feeling of peace, the scientific community has begun to empirically measure what happens in our body and brain during the night. The bad news is that, objectively, your rest could be suffering much more than you realize. Data under the microscope. An exhaustive study published in the scientific journal Scientific Reports decided to put exact figures on this phenomenon. Researcher Brian N. Chin and his team analyzed the habits of a representative sample of more than 1,500 adults in the United States. The results revealed that sleeping with pets is directly associated with poorer perceived sleep quality and greater severity of insomnia symptoms. Interestingly, the impact is not identical with all animals. Research analyzes showed that this negative effect on human sleep is strongly associated with dog owners, but no evidence was found that the same damage occurs when sleeping with cats. This difference may be due to the fact that dogs have greater sensitivity to external stimuli, waking up more easily to the noise of cars or barking in the neighborhood. The main problem lies in the sleeper’s self-deception. The author of the study highlights a surprising fact: 93% of people who slept with their pets firmly believed that their pets had a positive or neutral effect on their sleep. This disconnection between perception and biological reality is also supported In another study carried out on 12 women; Although the monitoring devices showed that the dogs constantly interrupted their rest, they rarely reported these interruptions the next morning. Why do we rest worse if we feel good? Dr. Vsevolod Polotsky, a sleep researcher at Johns Hopkins University, explains that the sleep of dogs and cats is not continuous; They inevitably move, bark, scratch or walk on the bed and on us. All this nocturnal activity causes what experts call “microawakenings.” Neurology professor Kristen Knutson details that these brief interruptions, which we are often not even aware of, are extremely disruptive because they abruptly take us out of the deep sleep phase. Worse yet, they have been associated with the release of the stress hormone cortisol, which significantly worsens overall rest. Furthermore, the investigation of Scientific Reports demolished one of the most widespread beliefs: the myth that the pet acts as a protective shield against anxiety before sleeping. Although high levels of life stress were associated with worse sleep, the scientists found no evidence that sleeping with the animal had a “buffering” effect that would protect the person from the ravages of stress. However, purely emotional logic has an undeniable weight in this equation. Sleeping with a pet, especially one with whom you have a close bond, can reduce the sense of perceived vulnerability and dramatically increase the feeling of security. We are faced with a complex exchange: our physical body experiences fragmented and less efficient sleep, but the animal’s mere presence helps emotional regulation by making us feel happy and protected. The verdict of the specialists. For animals, the experience of sharing sheets is undoubtedly positive. Dr. Dana Varble, veterinary director of the North American Veterinary Community, points out that animals Those who sleep with their owners experience higher levels of trust, as well as an increase in beneficial neurotransmitters such as oxytocin and dopamine, known as the feel-good hormones. However, in the case of humans, medical specialists warn about certain risk profiles: Respiratory problems: People with allergies or asthma are at risk of seeing their symptoms activated by being exposed to allergens such as animal dander for multiple hours in a closed space. Persistent allergens: Dr. Raj Dasgupta, pulmonologist, warns that allergens They also reside in the animal’s saliva and skin, which can cause watery eyes and continued nasal congestion throughout the night. Previous disorders: For those who suffer from chronic problems such as insomnia or sleep apnea, Dr. Polotsky is very clear when stating that bed sharing “is particularly harmful” and will prevent the patient from falling asleep again when they wake up. There are, of course, medical exceptions where the balance tips in favor of the animal. Service dogs trained for patients with post-traumatic stress disorder (PTSD) are of great help by knowing how to identify physical symptoms and wake their owners to interrupt nocturnal nightmares. Dr. Dasgupta also recognizes that, For people dealing with depression or anxiety, the pet can act as a comforting “big blanket” that effectively decreases distress. The unwanted companions. Beyond sleep quality, hygiene adds another layer of risk to nighttime living. A revealing pilot study published in the scientific journal Pathogens investigated what exact bacteria and parasites we take to bed. Of the 50 animals analyzed, 30% literally slept in bed, under the blankets with their humans. The most striking thing about this research was the great contradiction of the owner: although 42% of all respondents cited lack of hygiene as the main reason why pets should not be allowed into the bedroom, in practice, many ignored the risk and allowed them to sleep there. Microscopic measurements of the fur were surprising. The aerobic colony count (ACC) on the dogs’ hair exceeded the maximum limits of bacteria tolerated on hospital surfaces or in food preparation areas by 4 to 43 times. Even more graphic is that 64% of the dogs tested positive for … Read more

We’ve been sold melatonin as the ultimate harmless sleep supplement. Science does not think the same

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By taking a walk through any pharmacy, supermarket or online store, it is easy to find melatonin as the definitive solution to sleep problems and with the great claim of being something totally natural that our body secretes. Pills, drops, infusions or even gummies are some of the presentations in which we find a product that for many should not be available to everyone and that, in their opinion, It should be regulated like any other medicine. The alarm voice. The scientific community and regulatory bodies They are starting to sound the alarm and the central idea is clear: melatonin is not as harmless as it is often promoted and, according to experts, it should be treated with the same rigor as a medication, and not as a simple vitamin supplement. The labels. One of the biggest problems with melatonin, especially in countries like the United States where it is regulated as a dietary supplement, is the lack of strict control over its production. Here a study published in 2017 put a worrying fact on the table when seeing that there are a great variability between what the labels say and what the bottle actually contains. And when analyzing multiple brands, researchers found products that contained from 83% less melatonin than declared, to an alarming 478% more. And if that were not enough, the study detected the presence of serotonin in several of these supplements, which is a neurotransmitter that is regulated. It’s not something magical. Marketing has positioned melatonin as a universal solution for sleep that can be consumed without almost any type of control or limit. But here the different reviews conclude that its benefits are modest, without having a powerful hypnotic effect, but rather that its real usefulness lies in adjusting specific circadian rhythm disorders such as jet lag, so use should be selective and not routine. Furthermore, it is not without risks. One of the most striking is the incompatibility that taking melatonin may have. with anticoagulant medicationswhich requires medical supervision. This is something that a priori is not known to patients as they do not go to the doctor for a prescription and have melatonin available on a supermarket shelf. The silent danger. The rise of melatonin in gummy form has brought with it very serious collateral damage, since children may see it as a candy, which has led to an increase in visits to the emergency room in the United States due to excessive consumption of melatonin. In Spain, The approach taken is more strict, since drug regulatory agencies evaluate the safety of this substance in the key of medicinealthough you can buy it almost without any type of control when going to any supermarket. The positive part here is that the highest concentrations of melatonin can only be prescribed by a doctor in consultation so that the pharmacy can make a master preparation, considering it as just another medication, which is what is requested internationally. Images | James Yarema Slaapwijsheid.nl In Xataka | Someone has said that melatonin damages the heart. The reality, according to science, is that we can be calm

Science has measured how dinner affects sleep and the result explains why you wake up craving sugar

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Almost everyone has experienced an annoying night tossing and turning in bed after a heavy dinner or fat. Under this pretext, science has gone one step further to demonstrate that the relationship between what we eat and how we rest is completely bidirectional, making what we eat determine whether we are going to rest better or worse. And the most surprising thing is that sleeping poorly can cause us to need to consume more sugar the next morning. A Granada studio. In February 2026 the magazine European Journal of Nutrition public a revealing investigation led by the University of Granada, where researchers monitored the habits of 146 adults with obesity. To do this, they used special watches to analyze accelerometry over a period of 14 days, to later cross-reference the activity data with dietary surveys of what had been consumed throughout the day. Prohibited items. One of the most interesting conclusions reached was undoubtedly the relationship between certain foods and poor rest. And to be clear, the elements that should be prohibited at our dinner are the following: Saturated fats. Eating excess protein and, more specifically, eating red meat for dinner. French fries, or fried foods in general, reduce the quality of sleep. Alcohol is one of the classics on this topic, since, although it generates a feeling of sleep, it destabilizes its quality. Large meals cause slow digestion and cause nighttime awakenings, preventing you from entering into a deep and restful sleep. Highly recommended foods. On the contrary, the passport to restful sleep seems to lie in another type of nutritional profile. Interestingly, carbohydrates, often demonized at night, were associated with better rest in this study. Although we are not talking about sugar directly from the sugar bowl, but rather complex carbohydrates, such as brown rice or potatoes, because help transport tryptophan to the brain. But in addition, the consumption of oily fish such as salmon or sardines is also recommended, since they are rich in omega-3 and especially tryptophan. The reasons. As we see, tryptophan is key in the diet to induce quality sleep, and it is no wonder. Biochemistry tells us that the tryptophan that we ingest through the diet is converted into serotonin and, subsequently, that serotonin is transformed into melatonin, the well-known sleep hormone. And for this chain to work we need very important factors such as vitamin B6, magnesium or zinc. But this also adds to a much less difficult digestion when talking about foods that are barely fatty and that do not require a lot of work on the part of our body and that do not invite reflux symptoms to appear that can be really annoying at night. Specific foods. With scientific support behind it We find the kiwi, since here a trial pointed out that eating two kiwis, one before going to sleep, reduces the time to fall asleep by 35%. But it also increases sleep duration by 13% due to its contribution of antioxidants and natural serotonin. Additionally, green leafy vegetables such as spinach, chard or lettuce provide magnesium and tryptophan. And if vegetables are not for you, we also have eggs, either boiled or in an omelet, which provides tryptophan and vitamin B6, along with the classic grilled chicken breast, which is also an excellent source of tryptophan. The rebound effect. However, the true clinical contribution of the research is to show that this problem is, in reality, a cycle that feeds on itself in a dangerous way. Here the researchers found that when participants experienced a poor night’s sleep, breakfast was marked by a higher consumption of sugars and a lower intake of fiber. Images | Slaapwijsheid.nl Debbie Tea In Xataka | We have accepted that “deep sleep” is the standard for sleep quality: science points in another direction

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