Who were the investigators, and what were the aims of the studies? Behavioral studies suggest that aerobic fitness training improves cognitive functioning in older adults and improves brain health in aging laboratory animals. In particular, research suggests that aerobic fitness may provide a means to improve brain health in aging humans. Erickson and his colleagues (2009) investigated whether older adults with higher levels of aerobic fitness showed greater brain volume, more specifically in the hippocampus (which is important for memory and learning) in comparison to older individuals with lower fitness levels.

How did the investigators measure the topic of interest? Aerobic fitness was measured in terms of cardiorespiratory fitness. This was assessed by maximal graded exercise testing on a motorized treadmill while the participant’s respiration, heart rate, and blood pressure were continuously monitored by a cardiologist and nurse. In order to get a behavioral measure of hippocampal integrity, a spatial memory task was administered. Finally, magnetic resonance
imaging (MRI) was used to analyze hippocampal volume. Who were the participants in the studies? Participants were 165 older adults (109 female;

56 male) between the ages of 59 and 81 years. All participants were screened for dementia to obtain a sample of mentally healthy older adults. It is important in this kind of study to screen participants to make sure they do not have previous head trauma, head or neck surgery, or other neurological conditions.

What was the design of the studies? This study used a correlational approach by examining the degree to which aerobic fitness was correlated with hippocampal volume density and the degree to which aerobic fitness was correlated with spatial memory. In addition, the researchers were interested in a more complex relationship: Does higher hippocampal volume account for the relationship between aerobic fitness and good performance on a spatial memory task?

Were there ethical concerns with the study? Participants in the study were provided with informed consent and also
received a physician’s clearance to engage in the maximal graded aerobic exercise test.

They were also closely monitored throughout the study by a physician. Thus, there were no ethical concerns.

What were the results? Results showed that higher aerobic fitness levels were associated with the preservation of hippocampal volume. Higher aerobic fitness levels were also associated with better performance on the spatial memory task. Furthermore, larger hippocampal volume was the most important predictor of better spatial memory functions.

What did the investigators conclude? Erickson and his colleagues concluded that higher levels of aerobic fitness are associated with the preservation of hippocampal volume (an important brain structure for learning and memory) in older adults. This, in turn, translates into better memory functioning. They warn, however, that clinical trials are needed to determine whether exercise fitness improvements can reliably treat or reverse hippocampal decay.

beyond an examination of training to improve cog­nitive skills to an examination of the influence of aerobic exercise. Dramatic findings regarding the

influence of exercise on cognitive functioning in older adulthood are described in detail in the How Do We Know? feature.

Concept Checks

1. What effect does environmental enrichment have on aging rodents?

2. Does environmental enrichment affect neural plasticity in aging humans?

3. What are the benefits of aerobic exercise on the developing brain?