Stretch-induced blood pressure moderation: A potential basis for the sense of well-being accompanying stretching of upper back and neck muscles.

Voluntary stretching of upper back and shoulder muscles is often associated with a sense of well-being of unknown cause. The goal of this study was to examine the impact of shoulder/upper back stretching on heart rate (HR) and blood pressure (BP) responses in healthy individuals. Twenty-four healthy individuals underwent continuous beat-to-beat HR and BP monitoring during active standing (AS) and during shoulder/upper back extension stretching. Measurements were compared using appropriate statistical tests. With AS, HR increased (median 24 bpm) and systolic BP decreased (median - 28 mmHg). Shoulder/upper back stretching elicited a similar BP drop but a lesser HR increment (p < 0.001). The HR increase per mmHg BP fall (∆HR/∆BP) was significantly lower during stretch than during AS (0.34 vs. 1.1 beats/min/mmHg; p < 0.001). Thus, the HR response with stretch-induced BP fall averaged only 30.9% of that seen with AS. Shoulder/upper back muscle stretching induces transient BP reduction with only limited compensatory tachycardia compared to hypotension during AS. These findings suggest a neural reflex mechanism possibly initiated by muscle mechanoreceptors, with predominant vasodepression that may contribute to relaxation and a sense of well-being.