RELATED: If You Can’t Stop Doing This at Night, Get Your Thyroid Checked. An April 2021 study found that rapid eye movement sleep behavior disorder (RBD) may be an early sign of Parkinson’s disease. The study concluded that people with RBD are experiencing altered blood flow to the brain, which can result in a lack of oxygen in the brain tissue. Researchers suggest that down the line, this can cause symptoms of Parkinson’s, making RBD an early predictor of the disease.ae0fcc31ae342fd3a1346ebb1f342fcb A statement from Aarhus University in Denmark, where the study was conducted, said that signs you may have RBD include flailing your arms and kicking in your sleep. According to Sleep Foundation, punching, sitting up, jumping out of bed, and even minor movements of your limbs could all be signs of RBD, as well as talking, yelling, or screaming in your sleep. RELATED: If You’re Sweating at Night, It Could Be a Sign of These Kinds of Cancer. During normal REM sleep, the muscles in your body are temporarily paralyzed while your brain maintains similar activity to when it’s awake. However, people with RBD don’t experience normal muscle paralysis, allowing the person to physically act out their dreams, Sleep Foundation explains. RBD affects between 0.5 to 1 percent of adults, and is more common in people over the age of 50 and in men. More men are also diagnosed with Parkinson’s disease. The brain needs an ample flow of blood and oxygen to do its job. When that flow is decreased, it can negatively affect the brain. “We believe that the same disease processes that cause disrupted sleep also affect the ability to control the blood flow in the brain, which can lead to a lack of oxygen in the brain tissue,” Simon Fristed Eskildsen, PhD, one of the study authors explained in the statement. As the study notes, “The changes in the brain are associated with reduced neurotransmitters, meaning that nerves in the brain have trouble controlling the blood vessels.” The depletion of the neurotransmitter dopamine has been linked to Parkinson’s disease, as documented in a 2013 study published in Sleep Medicine Reviews and a 2016 study published in the Journal of Clinical Sleep Medicine. RELATED: For more health content delivered straight to your inbox, sign up for our daily newsletter. Thrashing around in your sleep isn’t the only early sign of Parkinson’s you need to watch out for. According to the Parkinson’s Foundation, other early signs include tremors, small handwriting, loss of smell, trouble walking, constipation, low voice, dizziness, fainting, and hunching over. If you notice any of these symptoms, talk with your doctor to find out if you could be dealing with Parkinson’s disease. RELATED: If This Body Part Hurts You at Night, See Your Doctor.