Tension headaches are the most common type of headache and are often caused by muscle tension or stress. Here are seven common causes of tension headaches: Stress: Stress and anxiety can cause tension headaches by activating the body's stress response, which can lead to muscle tension and pain. Poor posture: Poor posture, such as sitting or standing in an awkward position for an extended period of time, can lead to muscle tension and tension headaches. Eye strain: Staring at a computer screen or other electronic device for long periods of time can cause eye strain and lead to tension headaches. Dehydration: Dehydration can cause muscle tension and contribute to the development of tension headaches. Sleep deprivation: Not getting enough sleep or poor-quality sleep can lead to tension headaches. Caffeine: Consuming too much caffeine can cause muscle tension and contribute to the development of tension headaches. Hormonal changes: Changes in hormones, such as those that occur during.