June 12, 2025, 11:35 am | Read time: 5 minutes
Prolonged sitting is known to have negative effects on health. To best counteract this, one should engage in sufficient physical activity at other times—a logical consideration. However, when it comes to the risk of developing Alzheimer’s, this seems to be of little help. This is how the results of a new study should be interpreted. FITBOOK author Laura Pomer delves deeper into the topic.
Age is the most significant risk factor for Alzheimer’s. Additionally, other circumstances and lifestyle habits can contribute to the disease. These include smoking, social isolation, excessive alcohol consumption, and lack of exercise. But what exactly does “lack of exercise” mean? According to the World Health Organization (WHO), it occurs when individuals engage in less than 150 minutes of light physical activity per week. So how should it be assessed if someone spends many hours sitting due to their job but also exercises regularly? A study investigated this—specifically, whether prolonged sitting could be a potentially modifiable risk factor for developing Alzheimer’s.1
Overview
Study on the Significance of Sitting as a Risk Factor for Alzheimer’s
Prolonged sitting is not beneficial for the body. It is suspected of increasing the risk of various chronic diseases, as the authors note, including type 2 diabetes and cardiovascular diseases. However, the impact on cognitive performance is not yet sufficiently clarified. In a 2023 study reported by FITBOOK, the potential danger of lack of exercise for dementia was seemingly refuted.2 Conversely, several studies have demonstrated a positive effect of exercise on brain function.3
There is evidence that prolonged sitting can promote cognitive decline. Researchers suspect that this accumulated lack of exercise disrupts the function of blood vessels in the brain and promotes inflammation, leading to reduced synaptic plasticity. This is a significant mechanism for learning and memory performance. Given this possible connection, lack of exercise could be particularly critical for carriers of the APOE-ε4 gene, which is now well-established as a genetic risk factor for Alzheimer’s.4 The aim of the study was to substantiate this suspicion with data.
Details of the Study
The study involved 404 adult volunteers over the age of 50. At the start of the study, they wore activity trackers for a week, which allowed researchers to determine the average physical activity of the men and women. The results were generally positive: about 87 percent of the study participants met the WHO’s recommended minimum of 150 minutes of exercise per week.
In the following approximately seven years, researchers conducted regular cognitive tests with the participants. They also subjected the subjects to imaging studies to assess their brain health through scans.
Observations
The analysis showed that participants who spent a lot of time sitting—even if they otherwise moved relatively a lot—performed worse cognitively. The changes were particularly pronounced in participants who carried the previously mentioned APOE-ε4 gene. Moreover, the brain scans even showed signs of neurodegeneration, such as shrinkage in the hippocampus area (technical term: hippocampal atrophy). This brain region is crucial for memory function and is one of the first to be affected by damage in Alzheimer’s disease.
Possible Significance of the Study
“The study underscores the importance of reducing sitting time,” explains Angela Jefferson, co-author of the study, in a press release.5 This is particularly relevant for older adults with an increased genetic risk for Alzheimer’s disease. For brain health, it is crucial to take regular breaks from sitting throughout the day. The publication does not specify exactly how many hours of sitting are particularly critical.
Several other questions remain unanswered. For example, the researchers do not address whether beneficial behavioral changes could potentially reverse problems already caused by sitting. It would also be interesting to know whether engaging in more intense sports—compared to moderate exercise—would be more suitable as a “countermeasure” to more effectively offset the negative impact of sedentary activities. FITBOOK has reached out to the authors and eagerly awaits a response.
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Limitations
It is important to note the limitations. With only 404 participants, the study was relatively small. The authors also point out that the participants were not ethnically diverse and that most of them were well-educated. This limits the generalizability of the results. This also applies to the relatively high average level of physical activity determined. The study methodology itself has certain weaknesses, including the fact that the activity trackers were only used during a single sample week. The influence of other risk factors on Alzheimer’s risk was not considered in the evaluation.
Conclusion on the Link Between Sitting and Alzheimer’s Disease
The study results illustrate that prolonged sitting is an independent risk factor for Alzheimer’s—even when the recommended amount of physical activity per week is achieved. People with a genetic predisposition should, therefore, specifically focus on interrupting long periods of sitting in their daily lives. While further research is needed to determine the exact mechanisms and thresholds, the study provides important insights for prevention strategies in older age.