At 50, some people have a better memory than others and experience less cognitive fog. Lifestyle factors may play a role in this variability. Specifically, physical fitness at 25 could predict memory performance in middle-age: the fitter, the better the memory.
In 1985–1986, 2,747 participants aged 18 to 30 years were recruited in the community-based Coronary Artery Risk Development in Young Adults Study. Their cardiorespiratory fitness (CRF) was then evaluated thanks to a treadmill run, along with their cholesterol levels, blood pressure, etc. Most were moderately fit with an average time to exhaustion of 10 minutes.
Twenty-five years later, almost 2,000 of the same participants, now ages 43 to 54, were asked to repeat their treadmill run. They also completed cognitive tests to evaluate their memory and executive functions (high-level functions that allow us to switch from task to task, plan actions, inhibit behaviors, etc.)
Results showed that individuals who had been the most fit as young adults (i.e., with a time to exhaustion over 10 minutes) were the ones who performed best on the cognitive tests in middle age. The authors of the study consider that the difference they observed could be translated into a year’s worth of difference in normal brain aging.
Interestingly, the scientists also observed that participants who became fit during the 25-years interval also showed better cognitive scores in middle-age, compared to participants who had not improve their fitness over the years.
This study confirms that our lifestyle impacts how our brain ages. What we do on a daily basis, when we are young as well as throughout our life, will affect our memory performance in middle-age and later.
Physical exercise matters for brain health for two reasons. First it contributes to a good blood flow to the brain, preventing cardiovascular problems. Second, it triggers the release of BDNF (brain-derived neurotrophic factor), a growth factor that allows neurons to thrive.
In sum: To keep the brain fit, it is as important to exercise physically as it is to exercise mentally.
Reference: Zhu et al (2014). Cardiorespiratory fitness and cognitive function in middle age. Published online before print April 2, 2014, Neurology.
More on physical exercise and the brain: