Tim Allen. This is the latest accepted revision, reviewed on 7 April 2017. For those of the same or a similar name, see Timothy Allen (disambiguation). Timothy Allen Dick (born June 13, 1953), known professionally as Tim Allen, is an American actor, comedian and author.
Not necessarily. Some of the symptoms of low oxygen can be shortness of breath, fast heart rate, changes in the color of the lips and fingernails, but some people will have a low oxygen level without experiencing any of these symptoms. Others may experience these symptoms without having a low oxygen level.
Humans need oxygen to live, but not as much as you might think. The minimum oxygen concentration in the air required for human breathing is 19.5 percent. The human body takes the oxygen breathed in from the lungs and transports it to the other parts of the body via the body's red blood cells. Each cell uses and requires oxygen to thrive. Most of the time, the air in the atmosphere contains the proper amount of oxygen for safe breathing.