Stroke is one of the leading causes of death and long-term disability around the world. It happens when blood flow to part of the brain is suddenly blocked or when a blood vessel in the brain bursts.
Without enough oxygen, brain cells begin to die within minutes. Some people survive strokes but are left with problems such as weakness, speech difficulties, memory loss, or trouble walking.
Doctors have long known that conditions such as high blood pressure, diabetes, smoking, obesity, and high cholesterol increase stroke risk. But now, scientists are discovering that simple physical changes in the body may also act as early warning signs.
A new study published in the journal Stroke suggests that muscle weakness, slower walking speed, and loss of muscle mass may all be linked to a much higher risk of stroke later in life.
The research was led by scientists at the Second Affiliated Hospital of Zhejiang University School of Medicine in China. The researchers analyzed health data from more than 480,000 adults who took part in the UK Biobank project. None of the participants had suffered a stroke when the study began.
The researchers followed participants for nearly 14 years. During that time, more than 11,000 people experienced strokes, including both ischemic strokes, caused by blocked blood vessels, and hemorrhagic strokes, caused by bleeding in the brain.
The study focused on a condition called sarcopenia. Sarcopenia is the gradual loss of muscle strength and muscle mass that often happens as people age. Many older adults notice they become weaker, lose balance more easily, or walk more slowly over time. Scientists believe this loss of strength may reflect deeper health problems inside the body.
To measure muscle strength, researchers tested grip strength using a handheld device. Participants were also asked to report whether they usually walked at a slow, average, or brisk pace.
The findings were striking. People with low muscle strength had a 30% higher risk of having any kind of stroke compared to people with normal muscle strength. Their risk of ischemic stroke was 31% higher, while their risk of hemorrhagic stroke was 41% higher.
Even a weaker hand grip appeared to matter. Lower grip strength was linked to a 7% higher risk of stroke. Walking speed showed an even stronger connection. People who reported walking slowly had a 64% higher risk of stroke compared to people who walked briskly.
Researchers also discovered that people with muscle loss who later suffered strokes were more likely to die than stroke patients without muscle loss.
The study helps explain why doctors often observe that physically weaker patients tend to have poorer overall health outcomes. According to study author Dr. Lu-sha Tong, weak muscles may serve as an early warning sign that the body is under strain from inflammation, poor metabolism, or other hidden health problems.
Scientists think several biological changes may connect muscle weakness to stroke risk. As people lose muscle, they often become less physically active, which can worsen blood pressure, blood sugar, and circulation. Chronic inflammation in the body may also damage blood vessels over time.
Walking speed may be especially important because it reflects the health of many body systems working together, including muscles, balance, heart function, lung function, and brain health. A brisk walking pace may signal stronger overall physical health.
The researchers also used a method called Mendelian randomization, which studies genetic patterns to estimate possible cause-and-effect relationships. Their results suggested that faster walking speed may truly help lower stroke risk rather than simply being linked to better health overall.
The study included adults between 37 and 73 years old. Researchers noted that participants with confirmed muscle loss were generally older, had lower body weight, lower education levels, and included fewer men compared to participants without muscle loss.
Importantly, the researchers emphasized that the study does not prove muscle weakness directly causes strokes. Instead, it shows a strong association between physical weakness and higher stroke risk.
The study also had some limitations. Some information, including walking pace, relied on self-reported data, which may not always be perfectly accurate. In addition, most participants were white adults living in the United Kingdom, so the findings may not fully apply to all populations worldwide.
Even so, the research highlights a potentially simple way to identify people who may face greater stroke risk long before symptoms appear. Quick physical function tests such as grip strength and walking speed could one day become part of regular health checkups.
The findings also send an encouraging message: improving physical strength and staying active may help protect brain health. Regular exercise, especially strength training and walking, has already been shown in many studies to improve circulation, reduce inflammation, and lower blood pressure.
Maintaining muscle strength may become even more important as populations continue to age worldwide. With dementia and stroke cases expected to rise sharply in coming decades, scientists are searching for practical ways to detect risk earlier and prevent disability before it starts.
If you care about stroke, please read studies that diets high in flavonoids could help reduce stroke risk, and MIND diet could slow down cognitive decline after stroke.
For more health information, please see recent studies about antioxidants that could help reduce the risk of dementia, and tea and coffee may help lower your risk of stroke, dementia.
The study was published in the journal Stroke.
Source: Zhejiang University School of Medicine.
