No effect of either heat therapy or aerobic exercise training on blood pressure in adults with untreated hypertension: a randomized clinical trial

Hypertension, a primary and preventable risk factor for cardiovascular and kidney disease, may be ameliorated by nonpharmacological lifestyle interventions such as aerobic exercise and heat therapy. Although both interventions have been demonstrated to reduce blood pressure in a variety of populations, there are no studies that have directly compared these methods for lowering blood pressure in adults with untreated hypertension. Forty-one adults (48 [35, 56] yr) were randomized to complete either 30 sessions of aerobic exercise training (<i>n</i> = 20) or heat therapy (<i>n</i> = 21) over 8-10 wk. Ambulatory and in-clinic blood pressure and markers of cardiorespiratory fitness, arterial stiffness, and renal function were measured at baseline (PRE) and after 30 heat therapy or exercise training sessions (POST). Twenty-four-hour ambulatory systolic blood pressure was not different following either aerobic exercise (PRE: 139 [134, 144] vs. POST: 140 [134, 145] mmHg; <i>P</i> = 0.65) or heat therapy (134 [128, 139] vs. 134 [128, 139]; <i>P</i> = 0.81) nor was 24-h ambulatory diastolic blood pressure after aerobic exercise (PRE: 85 [81, 89] vs. POST: 86 [83, 90] mmHg; <i>P</i> = 0.28) or heat therapy (81 [78, 85] vs. 81 [77, 85]; <i>P</i> = 0.44). In-clinic blood pressure was similarly unchanged following both aerobic exercise and heat therapy. These pressure responses, along with arterial stiffness and kidney function biomarkers, did not differ between treatment groups (all <i>P</i> > 0.05). These data suggest that, during an 8- to 10-wk intervention, exercise training and heat therapy have similar and limited impacts on blood pressure, arterial stiffness, and biomarkers of kidney function among adults with untreated hypertension.<b>NEW & NOTEWORTHY</b> Exercise training represents a crucial lifestyle intervention for improving blood pressure, yet many adults do not meet recommendations for physical activity. Heat therapy was tested against aerobic exercise training as a potential alternative lifestyle intervention. Neither heat therapy nor exercise training was effective for the treatment of hypertension.