Neurohumoral and ambulatory haemodynamic adaptations following isometric exercise training in unmedicated hypertensive patients

Objective:
Hypertension remains the leading modifiable risk factor for cardiovascular disease (CVD). Isometric exercise training (IET) has been shown to be a useful non-pharmacological intervention for reducing resting blood pressure (BP). This study aimed to measure alterations in office BP, ambulatory BP, cardiac autonomic modulation and inflammatory and vascular biomarkers following a programme of IET in unmedicated hypertensive patients.

Methods:
Twenty-four unmedicated stage 1 hypertensive patients (age 43.8±7.3 years; height, 178.1±7 cm; weight 89.7±12.8 kg) were randomly assigned in a cross-over study design, to 4-weeks of home based IET and control period, separated by a 3-week washout period. Office and Ambulatory BP, cardiac autonomic modulation, and inflammatory and vascular biomarkers were recorded pre and post IET and control periods.

Results:
Clinic and 24-hour ambulatory BP significantly reduced following IET by 12.4/6.2 mmHg and 11.8/5.6 mmHg in systolic/diastolic BP, respectively (p<0.001 for both), compared to the control. The BP adaptations were associated with a significant (p=0.018) reduction in the average real variability of 24-hour ambulatory BP following IET, compared to control. Cardiac autonomic modulation improved by 11% (p<0.001), baroreceptor reflex sensitivity improved by 47% (p<0.001), and interleukin-6 and asymmetric dimethylarginine reduced by 10% (p=0.022) and 19% (p=0.023), respectively, which differed significantly to the control period.

Conclusion:
This is the first evidence of durable BP reduction and wider CVD risk benefits of IET in a relevant patient population. Our findings support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of HTN.