A new study now finds that the relationship between physical and brain fitness varies in older adults by virtue of their sex. The study was published ahead of print in the Journal of Applied Physiology on Wednesday.
Cardio-respiratory fitness is the measure of how much, and how well, oxygen is delivered to the muscles during exercise. Furthermore, fitness level is also associated with changes in the brain’s nerve-tissue, called gray matter, and better cognitive function in later life.
Earlier, studies have found cardio-respiratory fitness to be related to how the brain functions during periods of rest. Nerve connectivity in the brain during rest changes with age.
The studies found that these changes can negatively affect cognitive function. However, “the neural basis of sex differences in the relationship between fitness and brain function in older adults has not been directly explored,” wrote researchers from York University and McGill University in Canada.
The study found researchers studying one group of men and one of women, both with an average age of 67.
The volunteers self-reported their typical daily physical activity level. The research team recorded the participants’ height, weight, age, sex and resting heart rate to determine their cardio-respiratory fitness.
They also administered imaging tests of the brain to record nerve function both within specific brain networks (local efficiency) and among all networks (global efficiency). The study found men to be having higher cardio-respiratory fitness levels than women. However, the women had higher local network efficiency and lower global network efficiency than the men.
This pattern of connectivity was more robust in the women and has been positively associated with executive functions, which are skills that contribute to being able to focus, pay attention and manage time.
Fitness levels, however, were more strongly associated with improving this brain efficiency pattern for men than women. The researchers wrote, “Our findings that (cardiorespiratory fitness) is associated with brain function in a sex-dependent manner underscore the importance of considering sex as a factor when studying associations between exercise and brain health in older adulthood.”