There is a connection between mental health and physical health. When our bodies are well-nourished and cared for, this can improve our brain health, which makes it easier for us to feel happier and present. For example, getting consistent sleep and exercise can help anxiety and depression ^1,2. However, getting the right amount of sleep and exercise can depend on your daily routine. Staying up late and sleeping in is perfectly normal from time to time but doing it too much can impact your sleep and activity schedule. New research shows that interfering with a healthy routine can affect your mental health³.  

The goal of this study was to see whether being active at different times of day makes a difference in peoples’ mental well-being. To do this, the researchers looked at data from the National Health and Nutrition Examination Survey (NHANES) study. This was a detailed study that examined many aspects of peoples’ health and lifestyle. One thing that was unique about the NHANES was that it tracked peoples’ physical activity using an accelerometer. An accelerometer is a device that a person wears that tracks their physical movement. The accelerometer data gathered in the NHANES allowed researchers to see which times of day people were most active. The researchers examined whether people showed more or less symptoms of depression based on what times of day they were most active. 

The study participants wore their accelerometers for one week. The researchers then analyzed the physical activity data using machine learning. Machine learning involves advanced techniques for finding patterns in large amounts of data. The researchers found three major patterns of daily activity, which they labeled morning-dominant, evening dominant, and all-day. People with a morning-dominant pattern of physical activity were most active in the morning and slowed down later in the day. People with evening-dominant activity were most active at night, and people with the all-day pattern remained active throughout the day. The researchers also tracked how often people stuck with an activity pattern throughout the week. For example, some people might show morning-dominant physical activity during the work week, but then show evening-dominant activity on Friday and Saturday.  

The researchers then compared how much depressive symptoms people experienced based on their average activity patterns. They found that people who were most active in the morning had the least depressive symptoms. Meanwhile, people who were usually most active at night showed more depressive symptoms. Depression among people with all-day activity were more similar to those with morning-dominant activity. There were also differences in how much people changed their activity patterns throughout the week. For example, some people showed morning-dominant activity on some days and evening-dominant activity on other days. Others showed mostly the same type of activity each day. The study results showed that people who were more consistent in the timing of their daily activity were less depressed. On the other hand, people whose patterns of activity varied throughout the week showed more depressive symptoms.  

Overall, this study had a unique way of showing that healthy routine matters for mental health. Consistency in your daily schedule can help reduce symptoms of depression. Of course, this research shows general patterns. It doesn’t mean that staying up late some nights or working a night shift will automatically make you depressed. What it does show is that scheduling your day to allow for consistent sleep and exercise will help you be happier and healthier.  

Accelerometer – a device that a person wears that tracks their physical movement. 

Machine learning – advanced techniques for finding patterns in large amounts of data. For example, your email uses machine learning to identify spam and sort it into your spam folder. 

1. Mikkelsen K, Stojanovska L, Polenakovic M, Bosevski M, Apostolopoulos V. Exercise and mental health. Maturitas. 2017;106:48-56. doi:10.1016/j.maturitas.2017.09.003 
2. Scott AJ, Webb TL, Martyn-St James M, Rowse G, Weich S. Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials. Sleep Medicine Reviews. 2021;60:101556. doi:10.1016/j.smrv.2021.101556 
3. Nawrin SS, Inada H, Momma H, Nagatomi R. Twenty-four-hour physical activity patterns associated with depressive symptoms: a cross-sectional study using big data-machine learning approach. BMC Public Health. 2024;24(1):1254. doi:10.1186/s12889-024-18759-5