Heat waves in European capital cities this summer claimed the lives of tens of thousands of people due to record temperatures. ^[1] Thami conducted preliminary research examining how many buildings have adequate shade from trees, finding that in London, Paris, and Madrid, more than 90% of buildings did not have enough shade to prevent urban heat island effects. ^[2] In London, emergency wards filled with elderly patients who were injured after fainting in the heat, while dry weather caused subsidence and cracks in homes. ^[3] Tree shade has been shown to reduce the heat absorbed by pedestrians by up to 18°C by preventing solar radiation from reaching heat-absorbing materials. ^[4] A meta-analysis of 20 studies found that a single bout of exercise reduces the hunger hormone ghrelin and increases fullness hormones including PYY, GLP-1 and pancreatic polypeptide. ^[5] A more recent systematic review and meta-analysis found that exercise suppresses appetite initially, but this effect wears off 30-90 minutes later. ^[6] A systematic review of exercise training in adults who were above a healthy weight or had obesity found a small increase in hunger levels while fasting, but no clear or consistent increases in post-meal or daily hunger, and exercise did not substantially increase average energy intake. ^[7] Research suggests that regular exercise can reduce the desire for high-energy foods and help reduce overeating. ^[8]