Blood pressure response to six-minute walk test in hypertensive subjects exposed to high altitude: Effects antihypertensive combination treatment Morin Lang a,d , Andrea Faini a , Sergio Caravita a , Grzegorz Bilo a,b , Cecilia Anza-Ramìrez c , Francisco C. Villafuerte c , Jose Luis Macarlupu c , Elisabetta Salvioni e , Piergiuseppe Agostoni e,f , Gianfranco Parati a,b, ⁎ a Dept. of Cardiovascular, Neural and Metabolic Sciences, S. Luca Hospital, Istituto Auxologico Italiano, IRCCS, Milan, Italy b Dept. of Health Sciences, University of Milano-Bicocca, Milan, Italy; c Laboratorio de Fisiologia Comparada, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru d Departamento de Ciencias de la Rehabilitación y el Movimiento Humano, Universidad de Antofagasta, Antofagasta, Chile e Centro Cardiologico Monzino, IRCCS, Milan, Italy f Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy abstract article info Article history: Received 17 March 2016 Received in revised form 29 April 2016 Accepted 30 April 2016 Available online 03 May 2016 Background: Limited evidence exists on blood pressure (BP) responses to exercise in hypertensive subjects exposed to high altitude, and on the effects of antihypertensive treatment in this setting. We aimed to asses BP response to submaximal exercise in hypertensive lowlanders acutely exposed to high altitude, and the effects of a calcium antagonist–angiotensin receptor blocker combination in this condition. Methods: 89 mild-hypertensive participants in HIGHCARE-ANDES study performed a six-minute walk test in 3 conditions: at sea-level off-treatment; at sea-level after 6 weeks of double-blind treatment with telmisartan 80mg + slow release nifedipine 30 mg or with placebo; on the first full day of permanence at 3260 m altitude under randomized treatment. Results: The distance walked in 6 min was reduced by about 10% at high altitude in both groups (p b 0.001) without treatment-related differences. Systolic BP increased at altitude in both groups, remaining lower on telmisartan/nifedipine than on placebo both before and after exercise (p b 0.001).The exercise-induced increase in systolic BP at altitude was blunted by active treatment as compared to placebo (+32.0 ± 19.8 vs +41.9 ± 23.3 mm Hg, p b 0.05). Diastolic BP was unchanged from sea-level to altitude in both groups, showing lower values on telmisartan/nifedipine than on placebo before and after exercise (p b 0.01). Oxygen saturation was sim- ilarly reduced in both groups before exercise at altitude, but after exercise it was higher on telmisartan/nifedipine than on placebo. Conclusions: In mild hypertensives, acute exposure to high altitude enhances the BP response to exercise. Such an enhanced response is effectively reduced by telmisartan/nifedipine combination therapy, without affecting exer- cise performance. © 2016 Published by Elsevier Ireland Ltd. Keywords: High altitude hypoxia Blood pressure Exercise Six-minute walk test Hypertension 1. Introduction There is worldwide an increase of leisure or professional activities at high altitude [1]. As a result of this, a growing number of sea level residents, including subjects with pre-existing cardiovascular condi- tions such as arterial hypertension, are acutely exposed to high altitude without previous experience nor preparation, unaware of the potential risks carried by high altitude hypobaric hypoxia exposure [2–7]. Blood pressure (BP) has been shown to increase during acute ex- posure to high altitude, both in healthy subjects and in patients affected by arterial hypertension [6,8,9]. However, scarce information is avail- able on the BP response to physical activity required by daily life, in par- ticular when considering hypertensive lowlanders acutely exposed to altitude. Six-minute walk test (6MWT) is a simple and inexpensive test, widely applied in several clinical settings to evaluate functional status and hemodynamic responses to submaximal exercise [10–14]. The few studies in which the 6MWT was applied at altitude have reported International Journal of Cardiology 219 (2016) 27–32 ⁎ Corresponding Author at: Department of Cardiovascular Neural and Metabolic Sciences, San Luca Hospital, Istituto Auxologico Italiano; University of Milan-Bicocca, Piazzale Brescia 20, Milan, Italy. E-mail address: gianfranco.parati@unimib.it (G. Parati). http://dx.doi.org/10.1016/j.ijcard.2016.04.169 0167-5273/© 2016 Published by Elsevier Ireland Ltd. Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard