A new study finds constantly engaging in negative thinking patterns may increase the risk of dementia (痴呆). In the study of people aged over 55, researchers found repetitive negative thinking (RNT) was linked to memory decline as well as the deposition of harmful brain proteins linked to dementia.

Lead author Dr Natalie Marchant said, “Depression and anxiety in mid-life and old age are already known to be risk factors for dementia. Here, we found that certain thinking patterns involved in depression and anxiety could be an underlying reason why people with those disorders are more likely to develop dementia.”

Over a period of two years, the study participants responded to questions about how they typically think about negative experiences, focusing on RNT patterns like reflection on the past and worry about the future. The participants also completed measures of depression and anxiety symptoms. Their cognitive function was assessed, measuring memory, attention, spatial cognition and language. Some of the participants also underwent PET brain scans, measuring deposits of two proteins which cause the most common type of dementia, when they build up in the brain.

The researchers found that people who exhibited higher RNT patterns experienced more cognitive declines over a four-year period and declines in memory, which are among the earlier signs of dementia, and they were more likely to have protein deposits in their brain. “We think that repetitive negative thinking may be a new risk factor for dementia as it could contribute to dementia in a unique way,” said Dr Marchant.

Co-author Dr Gael Chételat commented, “Our thoughts can have a biological impact on our physical health, which might be positive or negative. Mental training practices such as deep thought might help promote positive thinking, and down-regulate negative-associated mental plans. Looking after your mental health is important, and it should be a major public health priority, as it's not only important for your health and well-being, but it could also impact your eventual risk of dementia.”

How COVID-19 Affects Your Body

Doctors continue to learn about the short-term and long-term effects of COVID-19 on your body. For some people, It starts with basic flu symptoms. But it could eventually affect your lungs, liver, kidneys, and even your brain.

Usually the virus makes contact with you when a nearby infected person sends droplets(微滴) into the air by coughing, sneezing, or talking. It spreads easily between people within about 6 feet of each other. An infected person can spread these droplets, even if they don’t feel sick. The virus may infect you after you touch an object, like a doorknob(门把手), that has the virus on it. But that's not as common.

Once the virus enters the body, it usually settles in the cells that line your nose, sinus cavity(鼻窦腔), and throat. For most people, this is where it stays. Symptoms often follow, but you may not feel anything for up to 2 weeks, as the virus starts to invade(侵略) healthy cells and reproduce. You can transmit (传播) it to others even if you don't show any symptoms.

The first symptoms that typically appear include a fever, headache, sore throat, and dry cough. But what you'll feel can vary widely in this early stage. You may also have:

Some studies show that up to 40% of people with COVID-19 are “asymptomatic(无症状的).” That means they don’t feel sick or have symptoms. But the virus can still affect your body. X-rays and CT scans of some people without symptoms show lung damage including “ground-glass opacities,”a typical lung lesion(损害) in people with COVID-19.

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Exercise helps to keep us in good health. Doctors at the American Heart Association suggest getting at least 150 minutes of proper physical activity every week. Many people exercise for a few minutes every day or every other day. So, getting 150 minutes every week is easy.

But what about those times when you are sick? If you do not feel well, should you keep following your exercise habit? Following are the answers from health experts.

Edward R. Laskowski is a doctor at the Mayo Clinic. He and other experts have a general rule about exercising when you are sick. It is usually fine to exercise properly (not hard), he explains, if your symptoms are all “above the neck”. These signs may include a runny nose, sneezing (打喷嚏) or a sore throat.

Geralyn Coopersmith, a physical fitness trainer who has written several books on exercise offers similar advice. However, both Coopersmith and Dr. Laskowski suggest taking a break from exercising if signs of your illness appears “below the neck”. Pay special attention to symptoms such as chest congestion (胸闷), bad cough or pain in the stomach.

There are other symptoms that can tell you to avoid exercise. They include a higher than normal body temperature, a sense of feeling very tired, and widespread muscle pain.

Both Coopersmith and Dr. Laskowski suggest listening to your body. If you feel really bad, take a break and let your body rest. If you don’t feel too bad, these experts both suggest cutting down the amount of exercise. For example, if you usually run, take a quick walk instead.