Stress and muscle tension: causes and mechanisms

For many people, the first indicators of stress are felt in the body: their shoulders pull up, their neck becomes hard, their jaw clenches and their breathing becomes shallower. All of this is no coincidence. Stress is a protective reaction that mobilises energy and prepares the body for action. Among other things, the autonomic nervous system and the stress hormone axis are activated. This activation can increase muscle tone and cause certain muscles to remain tense for longer or more frequently than necessary. The postural and support muscles in the neck and shoulder area are particularly commonly affected.

Muscle tone describes the basic tension of the muscles. Even at rest, some muscle fibres remain active to help us maintain posture and react quickly. Tension is not a single diagnosis, but a term used in everyday language. This usually refers to a feeling of stiffness, pressure, pulling or restricted mobility. Tension can have many causes, for example prolonged sitting, one-sided strain, lack of sleep or stress. Several factors often work together.

The brain decides whether we experience something as stress. It assesses a situation as a challenge or threat and then initiates a coordinated response. Two systems play a central role here: the sympathetic stress response and the hormonal stress axis (Godoy et al., 2018; McEwen, 2007).

The sympathetic nervous system is the activating component of the autonomic nervous system. During acute stress, inner alertness increases: heartbeat and breathing accelerate, attention becomes focussed and the body directs energy towards what is deemed to be important in that moment. This makes evolutionary sense because it creates the ability to act. In the muscular system, this often manifests as increased basic tension or protective tension, for example when the shoulders and neck unconsciously stabilise.

At the same time, the hypothalamic-pituitary-adrenal axis can be activated, often referred to as the HPA axis for short. It controls the release of glucocorticoids such as cortisol. Cortisol helps to provide energy and support adaptation to stress. Prolonged stress can change the rhythm and level of cortisol secretion and this affects various body systems, including metabolism, immune system and sleep.

Stress does not automatically lead to pain or tension. However, it increases the likelihood of the body retaining a tense posture, especially when stress occurs frequently and recovery is insufficient. The following mechanisms are well described in studies and reviews.

Attention narrows under stress. Many people move less variably, hold their shoulders higher or stabilise their torso more. These unconscious protective strategies can be useful in the short term and support performance, for example under time pressure or when concentration is high. At the same time, however, it can result in prolonged, low muscle activity. In a systematic review, a moderate increase in muscle activity in the neck, shoulder, and forearm was described during computer work under workplace stressors (Eijckelhof et al., 2013).

Tension arises particularly easily when mental stress is combined with prolonged periods of sitting. When working at a computer screen, the postural muscles sometimes work at low intensity for long periods of time. If stress is added to this, activity can also increase (Eijckelhof et al., 2013). The body then switches less frequently between tension and relaxation. Yet it is this very variation that is important to keep tissues well supplied with blood and allow them to recover.

Stress is not just a feeling; it also influences communication between the nerves and the immune system. This can change pain processing, for example by increasing the perception of stimuli or making the body more sensitive to stress (Tong et al., 2023; McEwen, 2007). This does not mean that stress alone causes pain. However, it can cause existing complaints to last longer or recur more quickly, especially if there is a lack of sleep, rest and exercise.

Under stress, breathing often becomes faster and shallower. This can result in the auxiliary breathing muscles in the upper chest having to work more. Some people feel this as pressure in the sternum or tension in the shoulder girdle. In one study, brief breathing interventions were examined in the context of psychological stress, and muscle tension was measured using surface electromyography (Liang et al., 2023). However, the overall body of research shows that short breathing or mindfulness interventions can have very different effects, with outcomes varying depending on the technique and setting.

• Shoulders move upwards or forwards without you realising it
• Clenching your jaw or clenching your teeth, especially when concentrating
• Shallow breathing or frequent sighing
• Mental work without changing movement, for example long meetings without changing position
• In the evening, the feeling of a heavy neck, hard trapezius muscle or restricted rotation
• Restless sleep or rest feels too short

These signs are not automatically indicative of stress, but they can suggest that more rest and variation of movement in the daily routine would be beneficial.

Stress-related tension rarely involves a single measure. Instead, small, regular cues help the body, signaling to it: Now it’s safe, you can let go. The following ideas are suitable for everyday use and can be easily implemented in the office, at home or on the move. 

• Change position every 30 to 60 minutes, even if it is only for a short time
• Two minutes’ walk: around the office floor or to the printer
• Shoulder circles, open up chest, gentle neck movements without pulling
• Once a day, plan a slightly longer activity that you enjoy, such as a walk or bike ride

The benefit lies less in a single stretch than in the variation. The body learns to switch between tension and relaxation again. From the point of view of stress physiology, it is precisely this flexible adaptation that is key (Russell & Lightman, 2019; McEwen, 2007).

• Feet stable on the floor, pelvis neutral, shoulder blades slightly backwards and down
• Pull your chin back slightly, as if you were gently pulling the back of your head backwards
• Consciously raise both shoulders for 2 seconds, then slowly let them drop
• Inhale deeply once, exhale twice as long, three repetitions

The body does not distinguish clearly between real danger and sustained tension caused by time pressure.

• At least 30 minutes without a screen in the evening to calm the nervous system
• Regular sleep routine, if possible
• Short breaks between meetings, even if it’s just for a glass of water
• Social support: exchange with colleagues, family, friends

Many people find heat pleasant in cases of muscular stiffness. Cold is more likely to be experienced as helpful if something feels acutely irritated or swollen. This varies from person to person. If you are unsure, start with mild stimuli for a short duration.