<human>:  What are the effects of stress on human behavior?
<bot>: The effects of stress on human behavior are varied and can range from physical exhaustion to emotional outbursts. Stress can lead to difficulty concentrating, making decisions, fatigue, headaches, restlessness, irritability, excessive worrying, depressed mood, and feeling overwhelmed. Long-term exposure to high levels of stress can also lead to a weakened immune system, increased risk of heart attack, loss of appetite and sleeping difficulties.