Stress is physical, mental, or emotional strain or tension. Tension is mental or emotional strain, suspense, anxiety, or excitement .
Anxiety is a reaction to a real or imagined threat, a general feeling of uneasiness or dread.
Stress is not a disease and is a normal part of everyone's life. The most frequent undesirable reaction is anxiety. Anxiety is often accompanied by twitching or trembling , muscle tension, headaches , sweating , irritability , fatigue , nightmares , memory problems, sexual impotence , sleeplessness , dry mouth, or difficulty swallowing . The degree of anxiety is much more a function of the individual than the degree of stress. The risk of anxiety increases with stress, a family history of neurosis, fatigue or overwork, or the recurrence of situations that have been previously stressful or harmful.