Effects of Low-intensity Isometric Handgrip Training on Home Blood Pressure in Hypertensive Patients: a Randomized Controlled Trial

We examined if lower intensity isometric handgrip (IHG) training than usual load could significantly reduce home blood pressure (HBP) in treated Japanese hypertensive patients. Sixty patients (mean age, 66.9 years; 44.6% men) with high blood pressure to grade 1 hypertension level were randomly assigned to an IHG or control group. The IHG group performed IHG training for 12 weeks, followed by a 12 weeks of detraining. The control group did not any IHG training. The IHG training comprised four sets of 2-min isometric contractions at 15% of maximum voluntary contraction (MVC) or half than usual, including 1 min of rest between sets, for ≥3 days a week. At the end of the former phase, both morning and evening systolic HBP (HSBP) and evening diastolic HBP (HDBP) were significantly higher than those at baseline in the control group while neither morning nor evening HSBP remained unchanged in the IHG group. Morning HBPs increased at the end of the latter phase than those at the end of the former phase in the IHG group and remained unchanged in the control group. The change (Δ) in morning HSBP from baseline to the end of the former phase was smaller in the IHG group than that in the control group (Δ4.1 mmHg vs. Δ0.0 mmHg, p = 0.05). A similar tendency was observed after adjusting baseline HSBP and seasonal variation (p = 0.06). In conclusion, a 12-week IHG training at 15% of MVC significantly lowered morning HSBP by approximately 4.0 mmHg in treated Japanese hypertensive patients. This study showed that a 12-week IHG training at 15% of MVC lowered morning HSBP by about 4.0 mmHg in treated Japanese hypertensive patients. Continuous low-intensity IHG training may provide a stable hypotensive effect in high blood pressure to grade 1 hypertensive population.