Exercise Alone Can’t Protect Brain Health: Study

A recent study highlights the significant interplay between exercise, sleep, and cognitive health, shedding light on the importance of balancing physical activity and sufficient sleep for maintaining cognitive function as individuals age. 

The study, led by Dr. Mikaela Bloomberg, a research fellow at the Institute of Epidemiology & Health Care at University College London, delved into the connection between physical activity, sleep duration, and cognitive decline. While exercise has long been recognized as a crucial factor in overall health, including cognitive well-being, the study suggests that the benefits of physical activity may be closely tied to the amount of sleep individuals get. 

The research encompassed nearly 9,000 adults who were part of the English Longitudinal Study of Aging, a decade-long longitudinal study focusing on individuals aged 50 and older. These participants underwent a series of assessments, follow-up interviews, and cognitive testing over the study period. Importantly, the study excluded individuals with dementia diagnoses or those showing signs of cognitive decline. 

The study’s findings revealed that individuals with higher levels of physical activity who slept less than six hours per night experienced faster cognitive decline compared to those who exercised less frequently and were short sleepers. This suggests that adequate sleep is essential for reaping the full cognitive benefits of physical activity. Dr. Bloomberg emphasized the need to consider sleep and physical activity together when addressing cognitive health. 

The research unveiled a notable connection between exercise and sleep. Participants who engaged in higher levels of physical activity and slept between six and eight hours per night exhibited better cognitive function as they aged. Conversely, those who were less physically active and experienced poor sleep independently showed worse cognitive performance over time. Moreover, individuals who slept less than six hours per night exhibited a faster rate of cognitive decline. 

Notably, the study found that, despite advantages such as being younger, having a lower body weight, being married or partnered, and having lower rates of smoking, alcohol consumption, depression, and chronic illness, highly active individuals in their 50s and 60s who slept an average of less than six hours a night lost the cognitive advantage provided by exercise.

This group experienced cognitive decline at a rate similar to those who did not engage in regular exercise. The study’s findings indicated that a good night’s sleep is crucial for reaping the cognitive benefits of physical activity. However, the impact of sleep duration on the cognitive benefits of exercise appeared to vary with age. In participants aged 70 and older, the cognitive benefits of physical activity remained, even in those who slept less than six hours a night.

The study did not provide a clear explanation for this age-related difference. The authors of the study emphasized the complex relationship between physical activity and sleep, underscoring the need to consider these factors together when addressing cognitive health. The findings call for a more holistic approach to maintaining cognitive function as individuals age. 

The study also challenged the common myth that many people can function well on less than six hours of sleep. In reality, only a small portion of the population carries a specific genetic trait that allows them to thrive with minimal sleep. For most individuals, consistently sleeping less than six hours per night can have detrimental effects on their health, including increasing the risk of conditions such as stroke and heart disease. 

The study’s results serve as a reminder of the importance of prioritizing sleep as part of a healthy lifestyle. While some may believe they can function optimally on minimal sleep, the negative health implications are far-reaching. Short sleepers, those who consistently sleep less than six hours per night, face an increased risk of stroke, heart disease, diabetes, and other health conditions, especially when combined with factors like high blood pressure or diabetes. 

The study’s findings highlight the significance of cultivating healthy sleep habits. Rather than relying on sleeping pills, experts recommend focusing on sleep hygiene, which involves creating an optimal sleep environment. This includes maintaining a cool room temperature, keeping the bedroom dedicated solely to sleep (no working or watching TV), and avoiding exposure to blue light from screens before bedtime. 

Additionally, individuals should reconsider consuming caffeine in the afternoon and avoiding nighttime alcohol consumption, as it can disrupt sleep patterns. Establishing a consistent sleep schedule—going to bed and waking up at the same times every day, helps train the brain to develop a regular sleep pattern, ultimately improving the quality of sleep. 

Moreover, the golden rule of sleep is not to stay in bed awake for extended periods. If sleep does not come within 15 to 20 minutes, experts recommend getting up and moving to a dimly lit room. Engaging in a non-stimulating, mindless activity like folding laundry can help induce sleepiness. The goal is to train the brain to associate the bedroom with sleep, enhancing the ability to fall asleep when in bed. 

This study underscores the intricate relationship between exercise, sleep, and cognitive health. It demonstrates the necessity of balancing physical activity with adequate sleep to maximize cognitive benefits. The findings emphasize the importance of considering both factors together to promote cognitive well-being as individuals age. Furthermore, the study serves as a reminder that prioritizing healthy sleep habits is vital for overall health and should not be underestimated. 

Reference 

CNN, “Short sleep negates benefits of exercise for the brain, study says” https://edition.cnn.com/2023/07/06/health/poor-sleep-exercise-brain-benefits-wellness/index.html.