None listed
Conditions
Brief summary
The positive influence of exercise on cognitive decline in older adults is established and previous research has demonstrated that exercise increases the hippocampus volume, a region of the brain that is responsible for creating and storing new memories. However, it is not known whether the intensity of exercise is important for improving cognitive function, and what mechanisms are involved in cognitive improvement with exercise. In mice, we have demonstrated that exercise acts directly on the brain to increase the growth of new brain cells (neurons) in this brain region, and as a result, learning and memory are improved. A compound known as growth hormone appears to be an important mediator for the growth of new neurons. In older adults, growth hormone levels are much lower than in younger adults, but exercise can increase growth hormone levels in the brain and the blood, and the greater the exercise intensity the greater the increase in growth hormone. Therefore, based on our results from mice, it is thought that growth hormone may be an important link between exercise, brain health and cognitive function. This project will investigate whether exercise can increase the production of important growth factors, leading to hippocampus volume increase and improved cognitive function in older adults. We are recruiting adults aged 65-85 years, who will be divided into three groups to complete either low-intensity (very easy), moderate-intensity (easy) exercise or aerobic-interval (hard) exercise three times per week for 6 months. All exercise will be supervised and monitored for participant safety using heart rate and perceived exertion. Cognitive function, fitness, blood hormones and hippocampus volume will be measured before beginning exercise, at mid-point (3 months) and following the conclusion of the exercise program (6 months), as well as following a 6-month follow-up period after the conclusion of the exercise. Results will be analysed to see whether the exercise changed cognitive function, and whether this changed is related to factors such as blood hormones and hippocampus volume. Our approach is the first systematic, multimodal approach to investigate the mechanistic and phenomenological effects of exercise on cognitive function, with the unique interchange between animal and human investigation. The overall aim of this project is to translate the beneficial effects of physical exercise observed within mice to older adults and develop robust biomarkers that can be used to evaluate the effectiveness of exercise interventions on cognitive function in humans. Exercise is a relatively cheap, safe, accessible and available treatment, which can be offered systematically to a large aging population. Therefore, the use of exercise as a prevention and treatment for cognitive decline will potentially benefit a large portion of the population and may provide a significant economic benefit, at both an individual and a societal level.
Interventions
Participants will be randomised to one of three exercise interventions - low intensity (control), moderate intensity and aerobic intensity - and visit the exercise laboratory three times per week for six months. All training sessions will be supervised by qualified Exercise Scientists and Exercise Physiologists and will be conducted in small-group settings. Exercise intensity will be regularly monitored via heart rate and rating of perceived exertion (RPE) and will be recorded at regular interva
Participants will be randomised to one of three exercise interventions - low intensity (control), moderate intensity and aerobic intensity - and visit the exercise laboratory three times per week for six months. All training sessions will be supervised by qualified Exercise Scientists and Exercise Physiologists and will be conducted in small-group settings. Exercise intensity will be regularly monitored via heart rate and rating of perceived exertion (RPE) and will be recorded at regular intervals during the training sessions. Attendance, adherence and feasibility All data for training sessions will be recorded in an individual participant training diary, attendance will be calculated as the number of sessions attended divided by the total number of sessions available to attend. In the control group adherence will be calculated as the number of exercises completed, the moderate intensity group will be the total minutes where the target heart rate was maintained divided by the total exercise time, and the high-intensity condition adherence will be calculated as the number of intervals where the target heart rate is achieved divided by the total number of intervals completed. Attendance and adherence will be used to comment on the feasibility of the exercise paradigms in the target population. Moderate-intensity exercise training condition The moderate intensity exercise protocol will consist of 45-min continuous treadmill walking exercise at 60-70% of peak heart rate, with a 10-minute warm-up whereby participants increase the intensity of their walking to reach the target heart rate, a 30-minute core session, and a 5-minute cool down. Aerobic interval exercise training condition Participants randomised to aerobic interval training will complete a light 10-minute warm-up followed by four, four-minute working periods at 85-95% of peak heart rate interspersed by three-minute active breaks at 60-70% peak heart rate followed by a 5-minute cool-down, totalling 40-minutes of treadmill exercise.
Sponsors
The Univeristy of Queensland
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
65 Years to 85 Years
Healthy volunteers
Yes
Inclusion criteria
• Aged 65 – 85 years at the time of study inclusion • Able and willing to provide written informed consent • Able to communicate in English • No history of stroke or brain trauma • Stratified as ‘not high risk of experiencing a cardiac event during exercise’ according to the adult pre-exercise screening system (ESSA, 2012) • No presently diagnosed mental illness or significant cognitive impairment • Not be medicated for dementia • Healthy body mass index 18.5 – 30 kg.m-2 • Be able and willing to commit to the duration of the exercise program.
Exclusion criteria
• Younger than 65 years or older than 85 years of age • Illness or disability that preclude exercise or hinder completion of the study • Poorly controlled hypertension, cardiomyopathy, unstable angina, heart failure or severe arrhythmia, cancer, or chronic communicable infectious diseases • Current use of antipsychotics and/or antidepressants • Current or planned use of dehydroepiandrosterone, testosterone, transdermal oestrogens or other medications known to affect the growth hormone releasing hormone/growth hormone/insulin-like growth factor-1 axis. • Currently diagnosed significant psychiatric illness, such as depression or schizophrenia, or dementia • Any contraindication for 7 Tesla MRI investigation, including joint replacements, stents, bullet or shrapnel wounds and metal in the eye • Tobacco use, excessive alcohol intake (more than four alcoholic drinks per day), excessive caffeine intake (more than four cups of coffee per day) • Excessive exercise involvement (more than twice the weekly recommendations for adults or >600 minutes moderate to vigorous exercise) • Test results that indicate study participation is unsafe • Participation in conflicting studies.
Outcome results
None listed