Acute Cardiovascular Response To Mud-pack Treatment In Hypertensive Subjects Under Therapy

Hypertensive subjects often develop a blunted cardio-vagal baroreflex sensitivity and an imbalance between sympathetic and parasympathetic tone; this may reduce the adaptation of cardiac output and peripheral resistances to warm environments. Such reactions may be enhanced by anti-hypertensive drugs, especially those inhibiting the angiotensin II-mediated vasoconstriction. Therefore, the immersion in hot mud typical of SPA treatment may cause hypotension in these patients. PURPOSE: To evaluate the acute cardiovascular effects of mud-pack treatment in pharmacologically treated hypertensive patients. METHODS: 28 subjects (M/F 10/18; 67±11 yrs, m±SD) were divided in 2 groups, matched for age and anthropometric characteristics: normotensive (N) and hypertensive (H) subjects, treated with beta-blockers, ACE-inhibitors or angiotensin II receptor antagonists (no diuretics). Beat-by-beat systolic (SBP) and diastolic blood pressure (DBP)(finger pletismography), and heart rate (HR) were recorded before, in supine position (10 min), and during mud-pack treatment (mud temperature 42°C, 15 min). Cardiac output and total peripheral resistance were calculated from the computed aortic-flow waveform. HR variability spectral indexes of sympathovagal balance (HF, High Frequency; LF, Low Frequency and LF/HF ratio) were finally calculated. RESULTS: Compared to basal (pre-treatment) conditions, mud treatment tended to decrease SBP (difference between mud immersion and basal condition; H: -6±16 mmHg; N: -3±5 mmHg), whereas DBP did not differ (H: -2±7 mmHg; N: 7±5 mmHg) in both groups. HR significantly increased (p<0.05) in both groups (H: 7±6 bpm; N: 8±4 bpm). Cardiac output decreased significantly (p<0.01) in H subjects only (H: -1.5±2.0 l/min; N: -0.5±1.6 l/min), whereas total peripheral resistances decreased in H and increased in N subjects (H: -160±237 l/min; N: 97±124 dyn.s/cm5)(p<0.05). LF/HF ratio slightly but not significantly increased in both groups (H: 0.1±1.5; N: 0.7±1.6), as a results of an increase in LF and a reduction of HF, the latter being significant (p<0.05) in H subjects only. CONCLUSIONS: Mud-pack treatment seems to be safe in pharmacologically treated hypertensive subjects. Partially supported by FoRST (Fondazione per la Ricerca Scientifica Termale, Italy).