Isometric Handgrip Home Training to Lower Blood Pressure in Hypertensive Older adulTs

Isometric Handgrip Home Training to Lower Blood Pressure in Hypertensive Older adulTs: a 20-week Assessor-blindEd raNdomized Controlled Trial

This Study evaluates the effect of 20 weeks of isometric handgrip (IHG) home training in adults aged 50 years or more. Half of the participants will serve as a control group and will only receive hypertension-guidelines on lifestyle changes.

Hypertension markedly increases the risk of cardiovascular diseases and overall mortality. Lifestyle modifications such as increased levels of physical activity are recommended as the first line of anti-hypertensive treatment. A recent systematic review showed that isometric handgrip (IHG) training was superior to traditional endurance and strength training in lowering resting systolic blood pressure (SBP). The average length of previous IHG training studies is approximately 7.5 weeks with the longest being 10 weeks. Therefore, presently it is unknown if it is possible to further lower blood pressure levels beyond the 10 week mark. Recently, the investigators developed a novel method for monitoring handgrip intensity using a standard Nintendo Wii Board (Wii). The primary aim of this study is to explore the effects of 20-weeks IHG home training facilitated by a Wii in hypertensive older adults (+50 years of age) in lowering SBP compared to usual care. Secondary aims are to explore if/when a leveling off effect on SBP will occur during the 20-week intervention period in the training group and to explore adherence and potential harms related to the IHG home training.

Methods: Based on previous evidence, the investigators calculated that 50 hypertensive older adults (+50 years of age) is needed to achieve a power of 80% or more. Participants will be randomly assigned to either an intervention group (IHG home training + hypertension-guidelines on lifestyle changes) or to a control group (hypertension-guidelines on lifestyle changes). Participants in the intervention group will perform IHG home training (30% of maximum grip strength for a total of 8 min per day per hand) three times a week for 20-weeks.

Inclusion Criteria:

1. Age +50 years old
2. Un-medicated (anti-hypertensive medicine) with resting SBP between 135-179 mmHg or hypertensive patient medicated with no change in treatment for ≥ 4 months with resting SBP between 135-179 mmHg

Exclusion Criteria:

1. Manifest cardiovascular disease (cerebrovascular disease, Heart failure, Chronic Kidney Disease, peripheral vascular disease, and advanced retinopathy (fundus hypertonus III-IV)).
2. Diabetes (any type)
3. More than three blood pressure regulating agents
4. Physical limitation preventing IHG training (e.g. missing an arm or musculoskeletal disorders).
5. Arthritis in the hand or carpal tunnel
6. SBP ≥ 180 mmHg (will be advised to see a doctor)