NCT05131217

Effects of Acute Exercise Intensity on Cerebral Blood Flow and Cognitive Function in Older Adults

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 13 (actual)
• Sponsor: University of Virginia · Academic / Other
• Sex: All
• Age: 65 Years
• Healthy volunteers: Accepted

Summary

This study will analyze the influence of acute bout exercise intensities (continuous moderate and HIIT) on middle cerebral artery velocity (MCAv) to identify which intensity elicits the greatest increase in CBF in older adults (65+ yrs). Additionally, this study will help verify positive correlations between MCAv and cognitive function. These findings are important in determining the optimal exercise prescription for increased resilience against the age-related cognitive degradation.

Detailed description

With an increasingly aging population, it is paramount that we further understand the changes that occur during aging, especially those which contribute to cognitive decline. Evidence shows that cognitive function is closely linked to brain blood flow. When comparing cerebral blood flow (CBF) between old and young individuals, older adults appear to have lower baseline levels of CBF. One of the principle determinants of CBF is CO2. Since exercise results in rises in CO2 production, changes in CBF can be monitored. Older adults appear to have diminished changes in CBF compared to younger individuals during moderate intensity exercise. This then leads to the idea that older adults may need a greater exercise stimulus (i.e. HIIT) to see these changes in CBF. However, the effects of HIIT on CBF in older adults is largely unstudied. Purpose: To analyze the acute influence of HIIT on middle cerebral artery velocity (MCAv) in older adults, and to verify the positive association between MCAv and cognitive function. Experimental Design: Recruiting 16 healthy adults age 65 and older. The study will require each participant to report to 4 visits: a screening visit, a control, a moderate intensity exercise bout, and a high intensity exercise bout. The order of the experimental visits will be randomized to each subject, and exercise bouts will be work-matched. During the experimental visits, MCAv, end-tidal CO2, MAP, and HR will be measured continuously. Vascular measures such as pulse wave analysis and pulse wave velocity will be taken pre- and post-exercise. Additionally, blood flow through the internal carotid artery and cognitive measures (n-back test) will be measured and administered pre-exercise, and at 15 mins, 30 mins, and 45 mins post-exercise. A two-way repeated measures ANOVA will be used to determine significant differences for time (pre vs. post measures) x condition (control/moderate/HIIT). Results: In the process of collecting data. Implications: If the study is successful in its findings, this could change how exercise is prescribed to older adults. It could also lead to the question regarding if a greater exercise stimulus (i.e. SIT) may be even more beneficial for these individuals.

Conditions

• Aging Well

Interventions

Type	Name	Description
OTHER	Acute bout of Continuous Moderate Intensity Exercise	In this experimental intervention subjects will cycle continuously at moderate intensity (VO2 corresponding to lactate threshold) until a 200 kcal equivalent energy expenditure is reached.
OTHER	Acute bout of High Intensity Interval Training	In this experimental invention subjects will alternate between 1 minute of high intensity cycling (watts corresponding to 85% VO2peak) and 1 minute of low intensity cycling (watts corresponding to 35-40% VO2peak) until a 200 kcal equivalent energy expenditure is reached.
OTHER	Control	In this intervention placebo, subjects will lay down on a flat, soft surface for 30 minutes in a dimly light room. They will not be allowed to use any electronic devices or read during this time to avoid potentially influencing continuous data recording.

Timeline

• Start date: 2022-01-14
• Primary completion: 2023-05-01
• Completion: 2023-05-01
• First posted: 2021-11-23
• Last updated: 2023-11-29

Locations

1 site across 1 country: United States