As the years pass, it can become harder to get a good night's rest. The most common sleep disorder in middle-aged and older adults is chronic insomnia, which for many translates to around three years of relatively sleepless nights. A new study suggests a popular, gentle exercise may improve sleep as effectively as the top insomnia therapy. Hong Kong University exercise physiologist Parco M. Siu and colleagues compared the first-line treatment for this sleep disorder, cognitive behavioral therapy for insomnia (CBT-I), with regular sessions of tai chi. Millions of people around the world practice tai chi, a low-impact martial art that originated in China, often referred to as 'meditation in motion'. **Related:One Form of Exercise Improves Sleep The Most, Study Finds** Given that science has shown similar styles of exercise (as well as meditation and mindfulness) can benefit sleep, researchers suspected tai chi may be a useful companion to existing treatments. The study recruited 200 ethnic-Chinese adults who were above the age of 50 and lived in Hong Kong. All participants had been diagnosed with chronic insomnia. Participants were prescribed a course of 24, one-hour group sessions of either CBT-I or tai chi (the 24-form Yang style, to be specific) with 100 people assigned to each group. Sessions of either CBT-I or tai chi were held twice a week, for three months. Insomnia remission rate and treatment response rate for CBT-I and tai chi. (Siu et al., _BMJ,_ 2025) By the end of these treatments, the CBT-I group reported a greater reduction in their insomnia symptoms than those in the tai chi group, with changes assessed using a common seven-question screening tool called the Insomnia Severity Index. But when the researchers assessed participants again 15 months later, the tai chi group had 'caught up', enjoying improvements in sleep quality and duration, quality of life, mental health, and physical activity level that were on par with the CBT-I group. Interestingly, 31 of the 85 tai chi participants who returned for the 15-month check-in had continued their tai chi practice after the intervention period, albeit at a lower frequency. Meanwhile, just 13 of the 82 CBT participants who returned for a follow-up assessment reported using the skills and knowledge they had acquired during their CBT sessions in the subsequent months. This suggests that tai chi's accessibility and ease of integration into people's lifestyles may benefit its long-term effectiveness. Chronic insomnia can have serious impacts on the body, placing individuals at a higher risk for cardiovascular disease, mental disorders, and cognitive impairment. It's important that people seek professional medical help for their chronic insomnia. CBT, unlike tai chi, has been proven to be an effective insomnia treatment with minimal side effects. But accessing CBT for insomnia can sometimes involve long waiting periods because of a scarcity of trained therapists, and depending on access to healthcare, appointments can be expensive or subsidized under limitations. Tai chi's accessibility and ease of integration into people's lifestyles may benefit its long-term effectiveness. (xavierarnau/Getty Images) This study suggests signing up for tai chi classes could be beneficial in getting a better night's sleep, especially in the long term, as a supplement to existing therapies. And there are a range of other health benefits associated with tai chi, too. "This finding supports the use of tai chi as an alternative approach for the long-term management of chronic insomnia in middle-aged and older adults," the authors write. This research was published in the _BMJ._

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Humans are not yet done cooking. We're continuing to evolve and adjust to the world around us, the records of our adaptations written in our bodies. We know that some environments can make us unwell. Mountain climbers often experience altitude sickness – the body's reaction to a significant drop in atmospheric pressure, which means less oxygen is taken in with each breath. And yet, in high altitudes on the Tibetan Plateau, where oxygen levels in the air people breathe are notably low, human communities thrive. **Related:Neanderthals May Never Have Truly Gone Extinct, Study Reveals** Over more than 10,000 years of settlement in the region, the bodies of those living there have changed in ways that allow the inhabitants to make the most of an atmosphere that for most humans would result in not enough oxygen being delivered via blood cells to the body's tissues, a condition known as hypoxia. Watch the video below for a summary of the research: frameborder="0″ allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen> "Adaptation to high-altitude hypoxia is fascinating because the stress is severe, experienced equally by everyone at a given altitude, and quantifiable," anthropologist Cynthia Beall of Case Western Reserve University in the US told ScienceAlert. "It is a beautiful example of how and why our species has so much biological variation." Beall has been studying the human response to hypoxic living conditions for years. In research published in October 2024, she and her team revealed some of the specific adaptations in Tibetan communities: traits that improve the blood's ability to deliver oxygen. To unlock this discovery, the researchers looked into one of the markers of what we call evolutionary fitness: reproductive success. Women who deliver live babies are those who pass on their traits to the next generation. The traits that maximize an individual's success in a given environment are most likely to be found in women who are able to survive the stresses of pregnancy and childbirth. Lo Manthang in Nepal, where some of the data was collected. (James J. Yu) These women are more likely to give birth to more babies. Those offspring, having inherited survivability traits from their mothers, are also more likely to survive, reproduce, and carry those same traits forward. That's natural selection at work, and it can be a bit strange and counterintuitive; in places where malaria is common, for example, the incidence of sickle cell anemia is high, because it involves a gene that protects against malaria. Beall and her team studied 417 women aged 46 to 86 who had lived their entire lives in Nepal at altitudes above 3,500 meters (11,480 feet). The researchers recorded their number of live births – ranging from 0 to 14 per woman, with an average of 5.2 – along with physical and health measurements. Among the things they measured were levels of hemoglobin, the protein in red blood cells responsible for delivering oxygen to tissues. They also measured how much oxygen was being carried by the hemoglobin. Interestingly, the women who demonstrated the highest rate of live births had hemoglobin levels that were neither high nor low, but average for the testing group. But the oxygen saturation of their hemoglobin was high. The results suggest that the adaptations are able to maximize oxygen delivery to cells and tissues _without_ thickening the blood – an outcome that would increase stress on the heart as it struggles to pump a higher viscosity fluid more resistant to flow. The noninvasive measurement of hemoglobin concentration and oxygen saturation. (Sienna R. Craig) "Previously we knew that lower hemoglobin was beneficial, now we understand that an intermediate value has the highest benefit. We knew that higher oxygen saturation of hemoglobin was beneficial, now we understand that the higher the saturation the more beneficial. The number of live births quantifies the benefits," Beall said. "It was unexpected to find that women can have many live births with low values of some oxygen transport traits if they have favorable values of other oxygen transport traits." **Related:Lead Exposure May Have Given Ancient Humans an Edge Over Neanderthals** The women with the highest reproductive success rate also had a high rate of blood flow into the lungs, and their hearts had wider than average left ventricles, the chamber of the heart responsible for pumping oxygenated blood into the body. Taken all together, these traits increase the rate of oxygen transport and delivery, enabling the human body to make the most of the low oxygen in the air respired. It's important to note that cultural factors can play a role, too. Women who start reproducing young and have long marriages seem to have a longer exposure to the possibility of pregnancy, which also increases the number of live births, the researchers found. Even taking that into account, however, the physical traits played a role. Nepalese women with physiologies most similar to women in unstressed, low-altitude environments tended to have the highest rate of reproductive success. "This is a case of ongoing natural selection," Beall said. "Understanding how populations like these adapt gives us a better grasp of the processes of human evolution." The research was published in the _Proceedings of the National Academy of Sciences_. _An earlier version of this article was published in October 2024._

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