Being an early bird, also called a morning person, and being more physically active are associated with lower risks of amyotrophic lateral sclerosis (ALS), according to a preliminary study released February 25, 2026, that will be presented at the American Academy of Neurology's 78th Annual Meeting taking place April 18-22, 2026, in Chicago and online.
The study does not prove cause and effect between these behaviors and the risk of ALS; it only shows an association.
ALS is a rare, progressive disease characterized by the degeneration of nerve cells in the brain and the spinal cord. People with ALS lose the ability to initiate and control muscle movement, which often leads to total paralysis and death. The average life span after diagnosis is two to five years.
Previous research suggests better sleep and more physical activity may reduce the risk of some neurodegenerative diseases, but results for ALS have been mixed. Our study found a sleep schedule that better matches daylight hours and more physical activity were related to a lower risk of ALS."
Hongfu Li, MD, PhD, study author of Zhejiang University, Hangzhou, China
The study included over 500,000 people with an average age of 57. Participants were followed for an average of 14 years, during which 675 people, or 0.14%, developed ALS.
Participants completed questionnaires at the start of the study about their sleep habits and physical activity.
For sleep, researchers determined chronotypes for all participants. Chronotype is a person's natural preference for when they are most alert and most sleepy. It is part of the circadian rhythm, the 24-hour sleep-wake cycle.
Researchers looked at two chronotypes. Morning chronotype, or early birds, was defined as people who preferred earlier bedtimes and wake times and reported peak productivity earlier in the day. Evening chronotype, or night owls, was defined as people who preferred later bedtimes and wake times and reported peak productivity later in the day.
Of participants, 277,620 were classified as early birds and 166,361 as night owls. Of early birds, 350 developed ALS. Of night owls, 237 developed ALS. Another 58,298 were excluded because their chronotype could not be determined.
After adjusting for factors such as age, sex and body mass index, researchers found being an early bird was associated with a 20% reduced risk of ALS compared to being a night owl.
Researchers also looked at sleep duration and found those who had between six and eight hours of sleep per night had a lower risk of ALS compared to those who had more or less sleep.
Researchers also found that greater physical activity was associated with a 26% lower risk of ALS.
They used metabolic equivalents (METs) to quantify energy expenditure. For each physical activity, METs were multiplied by the frequency and duration to obtain a physical activity score of MET-minutes per week. Vigorous activities such as running and cycling were assigned 8.0 METs, moderate-intensity activities like carrying light loads and household activities were assigned 4.0 METs, and lower-intensity activities such as walking were assigned 3.3 METs. The average physical activity level for participants was 2,645 METs-minutes per week.
Researchers found that among those who had more physical activity, 600 MET-minutes or more per week, 386 of 314,170 people developed ALS. Among those who had less, 107 of 70,946 people developed ALS.
After similar adjustments, 600 MET-minutes or more per week was associated with a 26% lower risk of ALS.
"While more research is needed to further explore these associations, promoting healthy lifestyle behaviors may represent a potential strategy for reducing the risk of ALS," said Li.
A limitation of the study was that 95% of participants were white people, so the results may not be the same for other populations.
The study was funded by the Chinese national level major research program.
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