Why is extreme heat so dangerous to the human body? CBC’s senior health and medical reporter Lauren Pelley went to Brock University’s Environmental Ergonomics Lab to find out. She ran for 20 minutes in a chamber set at 40 C while researchers measured the strain that put on her heart, weight and core and skin temperatures. For more on what the results showed and how to cool down your body during extreme heat, check out our YouTube Channel. Reporting by Lauren Pelley/CBC News #Canada #Toronto #Hea