Under Perens' definition, open source describes a broad general type of software license that makes source code available to the general public with relaxed or non-existent copyright restrictions.
1 Illnesses such as the flu or colds. Home treatment of your flu and cold symptoms usually will relieve lightheadedness. 2  Vomiting, diarrhea, fevers, and other illnesses that cause dehydration.  Very deep or rapid breathing (hyperventilation).
In contrast, lightheadedness cause by an arrhythmia can occur even when you are sitting or reclining. Other causes of lightheadedness include hyperventilation, panic or anxiety attacks, prolonged standing, and excessive fluid loss caused by vomiting, diarrhea, or sweating.