"Weekend Warrior" Workouts May Lower Dementia Risk as Effectively as Regular Exercise

Engaging in physical activity just once or twice a week – known as the “weekend warrior” approach – may reduce the risk of cognitive decline as effectively as more frequent exercise.

The study, published in the British Journal of Sports Medicine, posits a promising, manageable strategy for busy individuals to support brain health and potentially lower dementia risk.

Identifying potentially modifiable risk factors

Dementia is a debilitating condition that affects over 55 million people worldwide, with numbers projected to nearly double by 2050 as populations age. Characterized by the gradual decline of cognitive function, the disease disrupts memory, thinking and behavior, significantly impacting both the individuals affected and their families.

Cognitive impairment often precedes a dementia diagnosis, and therefore identifying potentially modifiable risk factors could be the key to efficient prevention strategies. Previous research has indicated a five-year delay in onset may halve the prevalence of dementia. Prospective cohort studies identified that leisure time physical activity is a major modifiable risk factor for cognitive decline and dementia.

Yet nearly all the research investigating these risk factors has come from studies in high-income countries – a factor that limits the scope of any findings. Considering the proportion of people living with dementia in Mexico and other Latin American countries is predicted to increase by around 200%, compared to a 75% increase in the UK and other countries in Western Europe, there is a need for further, global investigations.

Even low physical activity can impact dementia burden

The researchers behind the new paper used two sets of survey data from The Mexico City Prospective Study. The first data set was collected between 1998 and 2004, the second between 2015 and 2019. Over 10,000 participants (average age of 51) completed both surveys and were included in the study.

In the first survey, participants were asked whether they exercised or played sports and, if so, how many times per week, and for how long. They were then separated into four groups depending on responses:

• The no exercisers – 7,925 participants
• The “weekend warriors” who exercised/played sports once or twice a week – 726 participants
• The regularly active who trained 3 or more times a week – 1,362 participants
• A combined group comprising of the weekend warriors and the regularly active – 2,088 participants

The second survey utilized the mini mental state exam (MMSE) to assess cognitive function. A score of 22 or less out of 30 was used to define mild cognitive impairment.

After an average monitoring period of 16 years, 2,400 cases of mild cognitive impairment were reported. Cognitive impairment prevalence was identified in 26% of the no-exercisers, 14% among the “weekend warriors” and 18.5% among the regularly active.

After adjusting for key factors like age, education level, smoking status, sleep quality, diet and alcohol intake, the study found that "weekend warriors" were 25% less likely to develop mild cognitive impairment compared to non-exercisers. Additionally, when the score used to define mild cognitive impairment was changed to 23/30, 2,856 cases were identified and prevalence increased to 30% among the no-exercisers, 20% among the weekend warriors and 22% among the regularly active.

The study estimated that ~10% of mild dementia cases could potentially be prevented if all middle-aged adults engaged in physical activity at least once or twice weekly.

Compared to similar studies in Europe and North America, the cognitive health benefits observed were less pronounced. The authors suggest this may be because many people in Latin American cities engage in high levels of non-exercise physical activity, such as walking for transportation. This everyday activity may already offer some protective effect against cognitive decline, diminishing the observed benefit from exercise.

Economic implications and policy recommendations

Although further studies are needed to identify the protective underlying mechanisms on brain health at play, the team suggest several possible explanations.

“Exercise may increase brain-derived neurotrophic factor concentrations – molecules that support the growth and survival of neurons – and brain plasticity. Physical activity is also associated with greater brain volume, greater executive function and greater memory,” the authors wrote.

“To the best of our knowledge, the present study is the first prospective cohort study to show that the weekend warrior physical activity pattern and the regularly active physical activity pattern are associated with similar reductions in the risk of mild dementia,” they added.

The study estimated a potential annual savings of around USD $377.6 million in dementia-related costs in Mexico if middle-aged adults engaged in weekly physical activity. Promoting local initiatives, such as Mexico City’s Ciclovía Recreativa, the researchers say, could be a practical way to encourage physical activity and potentially reduce the dementia burden across Latin America.

Reference: O’Donovan G, Petermann-Rocha F, Ferrari G, et al. Associations of the ‘weekend warrior’ physical activity pattern with mild dementia: findings from the Mexico City Prospective Study. British J Sports Med. 2024. doi: 10.1136/bjsports-2024-108460

This article is a rework of a press release issued by BMJ Group. Material has been edited for length and content.