To investigate if autonomic nervous system function, reflected in cardiovascular variables, among patients with neck-shoulder symptoms (tension neck group (T)) differed from that in a symptom free control group (C), and to establish its relation with pain and psychological stress.
Twelve women with tension neck and nine controls in secretarial jobs were studied. They underwent an orthostatic test, deep breathing test, Valsalva manoeuvre, isometric handgrip test, and muscular endurance test. Pain was measured using visual analogue scales, and psychological stress by the Modified Somatic Perception Questionnaire (MSPQ). Plasma endothelin-1 (ET-1) was measured using high pressure liquid chromatography and radioimmunoassay.
Signs of psychological stress were significantly (p < 0.001) more common in group T than in group C. Mean resting heart rate in group T (77.8 (SE 2.9) beats/min; range 64-100) was significantly greater than that in group C (63.8 (3.1) beats/min; range 52-80) (p < 0.01). In the orthostatic test, the overall changes in R-R intervals during the first 40 heart beats after standing up and during seven minutes of testing differed significantly between the groups (p < 0.001, < 0.05, respectively). The increase in diastolic blood pressure in the three minute isometric handgrip test was significantly less in group T (19.4 (3.5) mm Hg; range -5 to 35) than in group C (30 (3.4) mm Hg; range 15-50) (p < 0.05). The MSPQ score in the study group (n = 21) correlated positively with resting heart rate (r = 0.462, p < 0.05) and negatively with increase in diastolic blood pressure (r = -0.514, p < 0.05). Plasma concentrations of ET-1 did not differ between the groups.
Increased sympathetic activity was found among patients having neck-shoulder symptoms. Local mechanisms may have influenced the cardiovascular changes observed during isometric testing in these patients.