Effects of accumulated exercise on risk factors for heart disease

INTERVENTION: Control group: The control group will be shown some stretching and relaxation exercises to do on a daily basis, the researcher will contact this group monthly either by telephone or text to check that they are doing their exercises. We anticipate that the actual stretching exercises will not alter the subject's activity levels, and monthly contact is included as an attempt to control for any 'attention effects' that might occur between the control and ER1. Exercise Routine 1 (ER1) group: The ER1 group, will be asked to incorporate 30 minutes of walking into their normal routine each day. They will be advised that this walking can be undertaken in three bouts of ten minutes each. This group they will be contacted by the researcher monthly to check that they are doing their exercise and also to provide support. Exercise Routine 2 (ER2) group: The ER2 group will be asked to incorporate 30 minutes of walking into their day, five days a week (as for ER1). However they will be contacted more regularly than the ER1 group (i.e. weekly rather than monthly). This will allow us to examine the usefulness of more regular contact on adherence and effect of intervention. As for ER1, contact will be by the researcher by text message or telephone to check that they are doing the exercises and to provide encouragement. CONDITION: Cardiovascular disease risk factors ; Circulatory System ; Cardiovascular disease PRIMARY OUTCOME: Arterial stiffness: measured using Pulse Wave Velocity (PWV) as an indirect measure. All PWV recordings will be on the same (left) arm for subjects, between the brachial and radial pulse sites of the arterial tree (identified by manual palpation). Pulse wave traces are calculated using the Labview program (Version 7.0). SECONDARY OUTCOME: 1. Anthropometry: height, weight (used to calculate body mass index) and waist/hip circumferences will be recorded using standardised methods (Jones et al. 1986). Mid‐upper arm circumference will also be measured. In addition percentage body fat will be measured using bioelectrical impedance.; 2. Physical fitness: evaluated using a sub maximal treadmill‐walking test, which will involve walking for 3 minutes at four progressive workloads (12 minutes total). Expired air analysis and heart rate will be used to predict maximal oxygen uptake and blood lactate will also be measured through a pin prick. Grip strength and flexibility will also be measured using standardised methods.; 3. Blood profiles: the role of abnormal lipids, inflammatory markers and homocysteine in the genesis of cardiovascular disease is well recognised. Thus fasting blood samples (30 ml) will be analysed for blood glucose, insulin (used to calculate homeostatic model assessment [HOMA]), lipids (total cholesterol, high density lipoprotein [HDL] cholesterol, low density lipoprotein [LDL] cholesterol and triglycerides), C‐reactive protein (CRP ‐ as a marker of inflammation), plasma homocysteine and related B vitamins and other novel CVD risk factors (including cholecystokinin [CCK], glucagon‐like peptide‐1 [GLP‐1], ghrelin [activated form], leptin, and adiponectin).; 4. Blood pressure: measured at each sampling time point using an automated BP machine and taking the average of two measurements INCLUSION CRITERIA: 1. Sedentary (self reported of less than 30 mins/day, moderate intensity activity during past 6 months) but otherwise apparently healthy non‐smokers 2. Male or female, aged 30 ‐ 55 years 3. Body mass index (BMI) 27 ‐ 35 kg/m^2 (i.e. overweight/obese)