Muscle tension is usually caused by stress, poor posture, overuse, or staying in one position too long. It can also be linked to dehydration, lack of movement, muscle strain, or certain medical conditions and medicines.

Common causes

  • Stress and anxiety: Your muscles may stay partly contracted when your body is under ongoing pressure.
  • Poor posture: Desk work, slouching, or awkward positioning can strain the neck, shoulders, and back.
  • Overuse or repetitive motion: Repeating the same movement in sports or work can make muscles tight and sore.
  • Too little movement: Long periods of sitting can reduce circulation and make muscles feel stiff.
  • Dehydration or low minerals: Low fluid intake, or low magnesium or potassium, can contribute.
  • Injury or illness: Minor strains, viral illness, chronic pain conditions, and some other diseases can all play a role.

When it matters

If the tension is new, severe, keeps coming back, or comes with weakness, numbness, fever, swelling, or widespread pain, it is worth getting medical advice. Muscle tension is often harmless, but persistent symptoms can point to an underlying issue.

What usually helps

  • Stretch gently and move regularly.
  • Adjust posture and workstation setup.
  • Drink enough water.
  • Rest overused muscles.
  • Reduce stress where possible.

TL;DR: Muscle tension most often comes from stress, posture, overuse, and inactivity, but dehydration and medical conditions can also be causes.