A study of the effectiveness of the Air Quality Health Index (AQHI) in reducing harmful effects of air pollution on the heart and lungs in adults 55 and over

INTERVENTION: 1. The intervention group will be asked to exercise indoors rather than outdoors and avoid other outdoor activity prior to physiological testing when the maximum AQHI is forecast to be 5 or higher (on the remaining days they will exercise outdoors). The intervention group will receive instructions for a simple indoor exercise routine that can be completed on designated days. 2. The control group will exercise outdoors daily CONDITION: Cardiac and respiratory health ; Signs and Symptoms ; Symptoms and signs involving the circulatory and respiratory systems PRIMARY OUTCOME: Weekly measures before and after 30 minutes of mild activity:; 1. Heart rate variability (Holter monitoring); 2. Endothelial function (Reactive Hyperemia Index ‐ Peripheral artery tone); 3. Oxygen saturation (finger oximeter); 4. Blood pressure (automated sphygmomanometer); 5. Fraction of exhaled Nitric Oxide (exhaled NO sensor); 6. Spirometric measures (spirometer); 7. Urinary oxidative stress markers (vascular endothelial growth factor (VEGF), 8‐isoprostane, malondialdehyde (MDA), 8‐hydroxydeoxyguanosine (8‐OHdG)) SECONDARY OUTCOME: Respiratory symptoms. INCLUSION CRITERIA: 1. Participants must be 55 years of age or older 2. Non‐smokers 3. Not exposed to environmental tobacco smoke at home 4. No seasonal allergies