In some cultures in the Northern Hemisphere, the astronomical March equinox (varying between 19 and 21 March) is taken to mark the first day of spring, and the Northern solstice (around 21 June) is taken as the first day of summer. In other traditions, the equinox is taken as mid-spring.
Circulation problems that cause dizziness. You may feel dizzy, faint or off balance if your heart isn't pumping enough blood to your brain. Causes include: 1  Drop in blood pressure.
One cause of sudden cardiac arrest is a heart attack. Sometimes, people who are having heart attack have a complication of sudden cardiac death if they don't get to the hospital soon enough, Goldberg said. Yet most heart attacks do not lead to sudden arrest, according to the American Heart Association.