Obesity, Cognitive Ability, General, Cardiovascular Disease
Conditions
Brief summary
One hundred participants from a combination of (a) local advertisements and/or (b) those whose details are held on a research database (of previous volunteers indicating willingness to be contacted about future studies) will be sought to volunteer for this study. Written informed consent will be gained following greater than 48 hours for the purpose of reading the Participant Information sheets. The study will then involve two stages (i) recruiting participants for a cross sectional analysis of the relationship between physical activity levels and cardiovascular and cognitive function, and (ii) a longer exercise training study in a subsample of these volunteers (i.e. participants who volunteer to exercise train). Participants for stage 1 will then visit the laboratory in the University on three occasions (over a three week period) to be assessed for body composition, exercise tolerance, current physical activity levels, cognitive function and arterial and cardiac health. Each visit will last for 60 - 90 minutes. Participants will then be provided with an accelerometer to wear for a period of one week in order to assess movement counts and sedentary behaviour. Stage 2 will include only those participants who have volunteered for the exercise training component (approx 60). These participants will then be randomly divided into two groups. Both groups will exercise three times per week for 12 weeks duration. Group 1 will exercise in a traditional manner at a moderate intensity, whilst the second group will exercise at a heavy intensity but in short bursts. Both groups will complete the same amount of work but in two differing modes. Both groups will attend the laboratory twice per week for supervised exercise sessions and also perform one home based 30 minute brisk walk per week. All participants will be re-examined at 12 weeks.
Detailed description
The study will involve two stages (i) recruiting participants for a cross sectional analysis of the relationship between physical activity levels and cardiovascular and cognitive function, and (ii) a longer exercise training study in a subsample of these volunteers. 100 participants for stage 1 will visit the laboratory in the University on three occasions (within a three week period) to be assessed for anthropometric outcomes, body composition, exercise tolerance, cognitive function and arterial and cardiac health. Each visit will last for 60 - 90 minutes. Participants will then be provided with an accelerometer to wear for a period of one week in order to assess movement counts and sedentary behaviour. Stage 2 will include only those participants who are happy to continue into the exercise training phase. These participants will then be matched for age and BMI and then randomly (on matched pairs) allocated to one of two groups. Both groups will exercise three times per week for 12 weeks duration. Group 1 will exercise in a traditional manner undertaking continuous exercise, whilst the Group 2 will exercise at a heavy intensity but in short bursts (interval exercise). Both groups will complete the same amount of work but in two differing modes. Both groups will attend the laboratory twice per week for supervised exercise sessions and also perform one home based 30 minute brisk walk per week. All participants will be re-examined at 12 weeks. Recruitment of participants One hundred participants from a combination of (a) local advertisements and/or (b) those whose details are held on a research database (of previous volunteers indicating willingness to be contacted about future studies) will be sought to volunteer for this study. Participants will be contacted via email/telephone/letter to provide information regarding this study. All volunteers interested in participating will be contacted to provide general information during a preliminary telephone screening interview. This will be used to check main inclusion and exclusion criteria. The women who fit these criteria will be sent the participant information sheet to read carefully and if still interested invited to attend the first laboratory visit for a screening session. Participants have greater than 48 hours to assess the participant information sheet before they attend this first visit when, if eligible, they will be asked to provide written informed consent. Laboratory Visits Visit 1 During this visit the study and all procedures will be explained in detail to all participants, and written informed consent will be taken. A thorough medical history will be obtained and participants will be asked to complete a Recruitment Information Questionnaire (RIQ) to confirm all inclusion/ exclusion criteria. Participants will complete the National Adult Reading Test (NART) which estimates premorbid intelligence levels. Participants will also complete a Physical Activity Readiness Questionnaire (PAR-Q) which will be reviewed to determine whether participants are fit to continue with the study. Simple measures of body weight, height and waist circumference will be taken. Participants will complete a practice version of the cognitive test battery to demonstrate the tests, ensure participants understand how to perform the tests correctly and assess compliance (effort). Participants will complete a cycling test on a stationary bicycle under the supervision of the investigator and a medic. Visit 2 The second visit will involve several measures of arterial health which requires participants to attend in a 12 hour fasted state. Blood vessel function will be assessed using a blood pressure cuff around the lower arm for a period of 5 minutes. Cardiac structure and function will be assessed using two-dimensional (2D) echocardiography. Vascular function will be assessed using ultrasound and applanation tonometry. All procedures are non-invasive. Percentages of body fat and muscle mass will be measured using bioimpedance. A 60ml blood sample will be taken which will be used to asses endothelial progenitor cell number and function, insulin sensitivity, cholesterol levels and is part of the assessment for health of the arteries and vascular system. Visit 3 On the third visit a cognitive function test will be completed, which requires participants to attend in a 12 hour fasted state. Participants will perform a 45 minute battery of cognitive tests. Following the cognitive tests, participants will be asked to complete a cognitive test evaluation questionnaire to assess both subjective and objective cognition. At the end of the third laboratory visit all participants will be provided with an ActiHeart accelerometer (Actigraph, Pensacola, USA) to wear for a period of one week in order to assess movement counts and sedentary behaviour. At the end of the seven days the accelerometer is given back to or collected by the team and the data downloaded. The three baseline laboratory visits plus the seven days using the ActiHeart accelerometer all come under stage 1 of the study. Participants will be asked to continue into the exercise training stage (stage 2), and willing volunteers will move through to the second stage of the experiment. All measures will be repeated at 12 weeks (78 hours to 5 days following cessation of the last exercise training session).
Interventions
BEHAVIORALInterval exercise training
Interval exercise sessions (INT) involving work:recovery ratios of 40 s at 70% delta work-rate followed by 80 s active recovery at 20 W. 70% delta (∆) is 70% of the difference between work rate peak (WRpeak) and work rate at the lactate threshold (WRLT) calculated as: 70%∆ =0.7(〖WR〗\_peak- 〖WR〗\_LT )+ 〖WR〗\_LT Where WR is work rate, LT is lactate threshold) Each session was for 30 min and this was undertaken twice per week for 12 weeks. One home based exercise session was incorporated per week.
BEHAVIORALContinuous exercise training (CON)
Exercise sessions involved cycling at 20%∆ work-rate peak for the duration of the session. This work-rate was chosen so that all participants in the group would be exercising in the heavy-intensity domain. To enable participants in the CON exercise group to complete the same amount of work (kJ) as the participants in the INT exercise group, the amount of work that would be completed if the CON participants completed an INT exercise session was calculated. Participants exercised for 26 min (varying to match interval group) twice per week for 12 weeks.
Sponsors
University of Leeds
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
35 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Sedentary women (exercise ≤2 day per week) * Pre-menopausal (age 35- 50 years) * BMI of ≥30 kg/m2 * Able to give informed consent . * Non-smokers * Vision sufficiently good to complete the cognitive testing (using glasses and/or lenses).
Exclusion criteria
* Male * BMI \< 30 kg/m2 * Clinically diagnosed with type 1 or type 2 diabetes * Resting/exercise ECG indicating significant ischemia, recent myocardial infarction or other acute cardiac event or other exercise related ECG abnormalities. * Unstable angina. * Uncontrolled hypertension. * Uncontrolled cardiac dysrhythmias * The use of antidepressant, antianxiety, or thyroid medication. * Dementia * Neurological disorder * Previous stroke or Transient Ischaemic Attack (TIA) * Musculoskeletal impairment or injury * Medication that has a direct effect on the brain and is likely to influence cognitive function. * Current smokers or those who have given up in the previous 6 months
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Maximal oxygen uptake (CPX) | Change at 12 weeks | Maximal oxygen uptake assessed during a ramp incremental cycle ergometry test. |
| Flow mediated dilatation | Change at 12 weeks | Percentage change in brachial artery diameter following cuff occlusion using doppler ultrasound. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Work rate peak | Baseline and 12 weeks | The peak work rate achieved during the maximal oxygen uptake assessment |
| Circulating angiogenic cell number | Baseline and 12 weeks | CD34+CD45dimKDR+ via Flow cytometry |
| Circulating cytokines | Baseline and 12 weeks | vascular endothelial growth factor |
| Arterial stiffness | Baseline and 12 weeks | Doppler assessed and Sphygmacor assessed changes in stiffness via pulse wave velocity |
| Cognitive function (Visual spatial learning scale) | Baseline and 12 weeks | — |
| Cognitive function (Tower of Hanoi) | Baseline and 12 weeks | — |
| Cognitive function (Grooved peg board) | Baseline and 12 weeks | — |
| Cognitive function (Visual verbal learning scale) | Baseline and 12 weeks | — |
| Lactate threshold | Baseline and 12 weeks | Lactate threshold estimated from pulmonary gas exchange criteria |
| Cognitive function (Corsi block tapping) | Baseline and 12 weeks | — |
| Physical activity level | Baseline and 12 weeks | Accelerometer assessed physical activity (Actiheart) worn on the hip |
| Blood pressure | Baseline and 12 weeks | Blood pressure |
| Body composition | Baseline and 12 weeks | Bioelectrical impedence analysis (BIOSTAT) assessment of fat mass |
| Cardiac function (echocardiography) | Baseline and 12 weeks | — |
| Cardiac structure (echocardiography) | Baseline and 12 weeks | — |
| Adhesion of cultured angiogenic cells to vascular smooth muscle cells | Baseline and 12 weeks | Number of cells adhering |
| Cognitive function (Bakan test)) | Baseline and 12 weeks | — |
| Blood borne (plasma) inflammatory marker | Baseline and 12 weeks | high sensitivity C reactive protein |
Countries
United Kingdom
Outcome results
None listed