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While chronic venous insufficiency is not considered a serious medical condition and it is treatable, it can be uncomfortable or painful. The condition is very common in older adults. Treatment typically can include medication to increase blood flow, elevating legs, minor procedures to improve blood flow, or surgery in...

22,860 次观看 • 1 年前 •via X (Twitter)

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Yoga and improved skin health and hair growth? India’s pseudoscience poster boy, Ranveer, aka Beerbiceps gets it embarrassingly wrong. Let us break it down. I am sorry this is lengthy, because – as per Brandolini's Law (aka the Bullshit Asymmetry Principle): It takes a lot more energy to refute bullshit than to produce it. Check out this video. In it, Ranveer “pseudoscience peddler” Allahbadia with over 8 million followers on YouTube and Instagram bullshits everyone in just 35 seconds. He showcases some major female movie celebrities and tells the viewers that the secret to their skin and hair is that they perform Yoga every day, especially a Yoga pose called the “Sarvangasana” or shoulder-stand or candle pose. His “scientific” explanation? The stance increases blood flow the scalp and head, and improves skin health and hair growth. This is utter nonsense. What happens to the blood flow, heart, head, and brain region when someone takes an upside-down stance? For that, you must know the meaning of one word – Homeostasis. Homeostasis is a self-regulating process by which human body maintains internal stability in its organ functions while adjusting to changing external conditions. This is also consists of “autoregulation,” the method by which an organ or tissue maintains blood flow despite a change in perfusion due to external (eg: body position changes) or internal (block in blood vessels) conditions. For example, we are normally supposed to walk on two legs or rest by sitting down or lying down. The heart rate, blood flow to all organs including scalp and brain is all maintained depending on the importance and metabolic activity of that organ. For example, at rest, highest proportion of blood flow is received by the liver (nearly 25% of cardiac output) which is 100ml/min per 100g liver weight. The brain receives 50ml/min per 100g weight, while the skin receives 1 to 3ml per 100g per minute. Organ tissues are usually considered as blood supply-dependent (e.g., heart and brain) and blood supply-independent (e.g., abdominal organs, kidneys, skin, and resting muscle) for oxygen delivery – meaning the latter WILL receive fixed amounts to maintain its functioning while the former requires changes to blood flow depending on various unusual situations. For example, in massive blood loss, the body will try to maintain blood flow into heart and brain rather than skin and muscle to maintain life. The blood flow is set in the body for proper functioning of organs and every time we try to change that flow, a healthy body will re-align that flow depending on the importance of the organ systems functions. So, when you do a shoulder stand or candle pose, the initial sudden change to the body position will be caught by the receptors in the blood vessels and heart which will re-align the flow to organs of importance, thereby maintaining critical functions that are required for health. Which means, the blood flow to the skin including the scalp, will be re-aligned to its required flow and DOES NOT increase to face and scalp or brain as India’s pseudoscience peddler mentions. In heavy aerobic exercise and changes to temperature related sweating or certain disease conditions, the skin blood can increase. Yoga is not a proper exercise as it is not an aerobic activity. Now Sarvangasana and blood flow – a study showed that heart and blood flow responses were NOT AFFECTED with this pose in healthy people. Even a complete head stand, called Sirsasana does not increase blood flow to the brain, forget the scalp skin, because of blood delivery homeostasis due to autoregulatory mechanisms. The claims for effects of Yoga on specific organs are complete bluff – a public duping started by B K S Iyengar who took Yoga to the international stage. Even in his authoritative books, he does not mention shoulder stand or candle pose to be useful for hair growth. In fact, he [nonsensically] mentions that shoulder stand will improve “thyroid health” (it does not), controls asthma (it does not), reduces disease of the throat (it does not) and prevents common cold (it does not, because common cold is caused by a virus, and not dependent on whether you stand, sit, lie down, and hang yourself upside down). Also, note that Sarvangasana (shoulder stand), Sirsasana (head stand) and Padmasana (lotus position) are the most common Yoga poses reported to cause an injury. In those with high blood pressure or heart disease, these poses may become life threatening. You can see those here here and here Yoga, especially shoulder or head stands do not improve skin health or increase hair growth by increasing blood flow. In fact, Yoga does nothing specific for organ systems functions since such evidence does not exist. A lot of pseudoscience peddlers who sympathize with Yoga will mislead you with many such magical benefits. So then, what specific exercise or action improves hair growth? We do not really know. There is some evidence, even though weak, for standardized scalp massages: good evidence for scalp cooling (prevents hair loss, may promote regrowth especially in chemotherapy patients) Speak with your Dermatologist on skin and hair health queries and not National-level baby-face poster boys of misinformation.

TheLiverDoc™

496,182 次观看 • 3 年前

Talk about dangerous liaisons! Abnormal brain vascular connections like a dural arteriovenous fistula (dural AVF) can be dangerous! This month’s AJNR SCANtastic is here to you some durable knowledge about dural AVFs! Dural sinuses sit inside dural leaflets and arteries that feed the dura also feed the walls of sinuses, like vasa vasorum. Arteries in the walls of veins are a natural connection between veins & arteries. Whether these are open depends on pressure. Normal venous pressure is not enough to open these connections, but if venous pressure is increased from thrombosis that pushes open these normal AVFs in the wall Now if fistula flow goes w/sinus flow, effect is relatively benign because dural venous sinuses are big & can handle extra flow. But if flow gets pushed backwards into cortical veins, flow is too much for cortical veins to handle & they are more likely to bleed. Presence of cortical reflux is dividing line if a fistula will have benign course or is likely to bleed Cognard classification defines dAVFs by the type of venous drainage. But you don’t have to memorize it. Just ask yourself: Can the venous outflow handle the flow (dural sinus vs cortical vein) & does it look like it is overwhelmed (venous ectasia)? In this month’s @the_AJNR, Itskeson et al. found 1/2 of dAVF pts had cognitive impairment. While more common w/cortical reflux, even pts w/o reflux had cognitive impairment that improved w/treatment This begs the question if there is any truly “benign” dAVF. Previously indications for treatment were venous reflux or debilitating pulsatile tinnitus. Perhaps we should be screening all dAVF patients for cognitive impairment and perhaps someday cognitive function will get incorporated into treatment decisions. Now you know the pathology of dural AVFs! Hopefully it stays w/you for the duration! But this only scratches the surface. Follow AJNR & check out the article for yourself:

Lea Alhilali, MD

11,498 次观看 • 1 年前