There are a number of symptoms that are associated with a hot flash. The initial symptom is a feeling of pressure in the head as the hot flash begins (in some patients this is called an aura as it signals an impending hot flash). The term "hot flash" is named for the sudden flushing and accompanying feeling of heat in the face and upper body. This wave of heat is typically followed by perspiration, as well as an increase in the heart rate. Hot flashes can also cause dizziness, nausea, fatigue, as well as feelings of weakness or faintness. Often the patient will feel a chill as the hot flash subsides. The symptoms of a hot flash can vary in intensity.
Hot Flash Mechanism
Hot flashes are a result of the body's way of dealing with increased heat. Hot flashes are commonly caused as the result of lowered levels of estrogen. According to Dr. Frederick R. Jelovsek at Wdxcyber.com, estrogen has an effect on the hypothalamus, which is a part of the brain which regulates the body's temperature. One of the effects that estrogen has on the hypothalamus is that it allows it to tolerate larger increases in temperature. As a result, a lack of estrogen can cause the hypothalamus to become very sensitive to changes in the body's temperature. When this happens, smaller changes will cause it to activate the body's "overheating" response, causing the blood vessels near the skin in the upper body and face to dilate, which causes the flushing and feeling of warmth.
Stress and Other Causes
Because hot flashes are a physiological response to changes in temperature, they are not only caused by the decrease in estrogen that commonly accompanies menopause. Aside from certain conditions (such as hyperthyroidism and certain kinds of cancers) that can cause flushing, stress can cause a hot flash. One of the results of the body's "stress" reaction (be it emotional or physical stress) is the release of epinephrine (also known as adrenaline) into the blood. This causes blood flow to increase which, as a result, leads to an increase in temperature. Because hot flashes are a response to an increase in temperature, stress can cause hot flashes.