Rapid heart beat
A rapid heartbeat happens when something disrupts the normal rate at which the heart pumps blood every minute. If this is experienced after spending time in high temperatures or in the sun, it could be a warning sign for a heat related emergency. When experienced with some or any of the other symptoms mentioned here, it is imperative to seek professional help.
A racing heart rate in these conditions is indicative of an increased pulse rate. This is due to the stress placed by heat on the heart while trying to keep the body cool.