Daily habits leave permanent traces in our brain

Have you ever thought that those extra hours of sleep from last week are still affecting your thinking skills? Or that yoga yesterday morning can boost your creativity next week? New research shows that our daily activities and well-being have a longer lasting effect on our brain than previously thought.

The study, published in the journal PLoS Biologyshedding new light on the complex relationship between our daily habits and our brain activity. By closely monitoring one person for five months, researchers found that the effects of sleep, exercise, heart rate and mood can still be seen in our brains for up to two weeks. Research director Ana Triana explains: “We wanted to look beyond isolated incidents. Our behavior and state of mind are constantly shaped by our environment and experiences. But we know little about how the brain’s functional connectivity responds to changes in our environment, physiology and behavior at different timescales, from days to months.”

Short-term and long-term effects
The research revealed two different response patterns in the brain: a short pattern that lasts less than seven days, and a longer wave that lasts up to fifteen days. The short wave mainly relates to issues that can change quickly, for example a bad night’s sleep which means you can’t concentrate all day. The long wave, on the other hand, has a more cumulative effect on things like attention span and memory. “We think of the short wave as more transient connections, such as a few nights of insufficient sleep that directly affect brain connectivity while you’re paying attention. Although this connection is affected, we think that the brain can ‘bounce back’ to the baseline. In our opinion, the long wave indicates a long-term interplay between factors and brain connectivity,” Triana tells Scientias.nl.

Another surprising discovery was the possible link between heart rate variability and the networks in our brain, especially when we are at rest. In other words, the study suggests that stress management is not only good for your heart, but also your brain.

The results are still limited
The study was unique in its design, with Triana serving as principal investigator and subject. In addition to brain scans, the research team used wearable technology and smartphones to get a complete picture of Triana’s daily activities and physiological responses. This design had advantages and disadvantages, the researcher says. “The most obvious limitation is that these results are individual, making it difficult to extrapolate to a larger population. Although the subject is human, individual lifestyles vary greatly. The special relationship between daily routines and brain activity we observed in one person may not apply to others. However, we expect change in brain connectivity in other individuals and we believe that people’s environment is also related to their connectivity over time.”

Difficult to reproduce on a larger scale
Triana says that she does not believe that such tests can be carried out on a larger scale because they are expensive and can be hard on participants. “Although it is difficult to conduct such trials on a larger scale due to the cost and burden on participants, they allow us to study and better understand internal variability. As we gain a better understanding of how external factors affect people differently, we can, for example, consider incorporating behavioral data from the past week into a mini- large studies. This can improve the translation of large-scale research into a more personal context.”

Personal health care
The findings, if replicated, can have a profound effect on how we view our daily routines. A good night’s sleep or a hard workout could have more of an effect than we think. Triana particularly emphasizes the importance of these insights for the future of personalized health care: “The connection of brain activity to physiological data and the environment of personalized health care can change. It opens the door to earlier interventions and better results,” concluded the researcher.