None listed
Conditions
Brief summary
AIM: The aim of this clinical trial is to investigate how different doses of aerobic exercise training affect cardiorespiratory fitness, brain blood flow, brain volume, and cognitive function in middle-aged (45-65 y) adults, and to translate this new knowledge into more individualised exercise prescriptions to better prevent the development of dementia. HYPOTHESIS: High-intensity interval training will improve cardiorespiratory fitness, brain blood flow, brain volume, and cognitive function to a greater extent than moderate-intensity continuous training. METHODS: In a single-blind, randomised-controlled trial, the study will follow a two-group parallel design. Groups will be matched on fitness, age, and sex, and participants will be assigned to one of two 12-week, work-matched, aerobic exercise interventions: 1) moderate-intensity continuous training (MICT; n =35), or 2) high-intensity interval training (HIIT; n = 35). These exercise modes were chosen as a means to investigate the most effective ‘dose’ of aerobic exercise training to improve fitness, brain blood flow, brain volume, and cognitive function. Briefly, the experimental protocol will consist of 1) screening, familiarisation, and baseline testing, 2) a 12-week aerobic exercise intervention with testing at the 6-week mark, 3) post-training testing, and 4) 12-week follow up testing.
Interventions
Intervention Group: High-intensity interval training
Participants will perform 12 weeks of supervised (exercise physiologist/scientist), work-matched cycling training, performed three times per week on a cycle ergometer in a laboratory. Training sessions will consist of between 4 to 7 x 4-min exercise intervals at an intensity of ~90% peak aerobic power, with each interval interspersed with 3 min of passive recovery. Each session will take ~35-55 min (with warm-up and cool down). Individualised
Intervention Group: High-intensity interval training Participants will perform 12 weeks of supervised (exercise physiologist/scientist), work-matched cycling training, performed three times per week on a cycle ergometer in a laboratory. Training sessions will consist of between 4 to 7 x 4-min exercise intervals at an intensity of ~90% peak aerobic power, with each interval interspersed with 3 min of passive recovery. Each session will take ~35-55 min (with warm-up and cool down). Individualised exercise intensity will be determined during a number of incremental exercise tests, which will be performed every 4 weeks during the intervention to ensure training progression (i.e., intensity from each individual incremental exercise test will determine the workload for the succeeding 4 weeks of training, which is expected to gradually increase at each 4-week training block). Training will be administered in groups of up to 4 participants per trainer, depending on participant availability. Adherence to the intervention (i.e., session attendance) will be monitored and documented by the principal investigator.
Sponsors
Victoria University
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used) (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
45 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
- Aged 45-65 - Able to participate in 36 exercise sessions over 12 weeks - Normal cognition on screening - BMI of 18 to 40 - Sign off from doctor to participate in the study
Exclusion criteria
- Involved in regular exercise training in the previous 6 months - Significant medical co-morbidities precluding participation in an exercise intervention (e.g., severe cardiac disease) - Contraindications to have MRI - Mild cognitive impairment on screening - Recent diagnosis (14 days), close contact, or symptomatic of COVID-19 - Underweight or morbidly obese (BMI < 18 or > 40) - History of any serious traumatic brain injury (e.g., ICU stay, rehab required, and/or a prolonged period of unconsciousness). - High blood pressure at rest (over 160/100 mmHg) - Current or ex-smoker (last 12 months) - Any blood disorders or brain tumours - Started any new medications (e.g., hormone replacement therapy) in the last 3 months
Outcome results
None listed