WORK-BASED ISOMETRIC EXERCISES EFFECT ON BLOOD PRESSURE: THE EEFIT STUDY

OBJECTIVE: To evaluate the effect of two workplace isometric exercise interventions on blood pressure in hypertensive adults. DESIGN AND METHOD: A randomized controlled multicenter clinical trial conducted in hypertensive (>130 mmHg systolic blood pressure (SBP)) 35 to 65 years old in work places in Colombia. Participants were assigned to either of two interventions: isometric handgrip dynamometer training at 30% of maximum strength (HGD) or wall squat (WS), or to a control group following standard recommendations. The interventions were performed at the participant's workplace and consisted of 4 sets of 2 minutes of sustained isometric contraction with 2 minutes' rest between sets, 3 times per week for 12 weeks. SBP and diastolic blood pressure (DBP) were measured using an automatic device (Omron) with a standardized protocol before and after the 12-week intervention. RESULTS: Pre and post measurements were completed by 105 hypertensive participants: mean age of 45 years (SD 9.5), 63.8% of which were men. In the HGD group (n = 38) there were significant decreases in SBP [Pre: 141 mmHg (SD 7.8), Post: 127 mmHg (SD 9.1) (p < 0.001)], and in DBP [Pre: 87 mmHg (SD 5.8), Post: 82 mmHg (SD 9.5) (p < 0.001)]. There were also significant decreases in the WS-group (n = 35) in SBP [Pre: 139 mmHg (SD 7.5), Post: 126 mmHg (SD 12.4) (p < 0.001)], and in DBP [Pre: 86 mmHg (SD 5.2), Post 82 mmHg (SD 8.1) (p < 0.001)]. In the control group (n = 32), there were no significant changes in either in SBP [Pre: 140 mmHg (SD 8.4), Post: 137 mmHg (SD 12.9)], or DBP [Pre: 86 mmHg (SD 5.0), Post: 85 mmHg (SD 8.0) (p = 0.71)]. CONCLUSIONS: Both workplace isometric training interventions resulted in significant and clinically relevant reductions in blood pressure in subjects with high blood pressure. The combination of effectiveness, modest time commitment (42 minutes per week) and ease with which the interventions can be implemented in the workplace setting makes them both attractive and practical options with minimal barriers for participation. Furthermore, WS can be performed without any equipment.