Hot flashes are closely related to other symptoms, particularly those of menopause. The most common symptoms related to hot flashes are:

• Night sweats (evening versions of “hot flashes”) and difficulty sleeping. Lack of sleep can contribute to women feeling tired, stressed or tense. In addition, severe hot flashes may increase the risk of insomnia, according to recent research.
  
  
• Irritability. In many cases, irritability accompanies sleep disturbances from nighttime hot flashes. However, not all women become irritable from disrupted sleep. Additionally, irritability may be a side effect of hormone replacement therapy.
  
  
• Other mood changes including mood swings and depression. Some researchers believe these emotions are a result of changes in the brain caused by a decrease in estrogen. Others think menopausal symptoms such as hot flashes, sleep problems and fatigue cause the feelings. Still others maintain that a combination of these factors is probably responsible.