Stiff and tense hands may be caused by improper sleeping posture, osteoarthritis, cervical spondylosis and other reasons. 1. Improper sleeping posture: when sleeping in an improper posture, the arm is overwhelmed, resulting in poor blood circulation in the arm, the hand is temporarily stiff and taut, and will generally return to normal after a period of time. 2. Osteoarthritis: a variety of reasons can lead to joint cartilage degradation, fracture and joint surface damage and other osteoarthritis. Osteoarthritis of the hand will make the hand stiff in the morning. The reason is that when you sleep or reduce your activities, the tissues around the affected joints ooze or become congested and edematous, causing tension in the muscle tissues around the joints, which leads to morning stiffness and discomfort. 3. Cervical spondylosis: Spinal cervical spondylosis is caused by overloading of the spine, trauma, etc. Its clinical symptoms are weakness, numbness and stiffness of the hands. During an attack of cervical spondylosis, the muscles of the upper extremities remain overstressed for a long time, and pathological changes may intensify during sleep, causing muscle spasms. Upon awakening, the muscles may be weakly contracted or unable to move effectively. In addition to this, hand stiffness and tightness may be due to diseases such as tendinitis of the fingers, muscle atrophy, and degenerative changes in old age. If the symptoms persist, it is recommended to seek medical attention to determine the cause of the problem and follow the doctor’s instructions for treatment.