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Fourteen participants, and the study did not examine normoxic exercise tolerance.\nexposure: Oral sildenafil 50 milligrams, with systolic pulmonary artery pressure, cardiac output and arterial oxygen saturation at rest and at maximum exercise\nevidence_span: {\"source_cache\": \"artifacts/sildenafil-research/15289213.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"9767ed0c1022cee4fb74a2caef80b8ac9afd40077da8b6d1651fe0e631fde136\", \"start_char\": 0, \"end_char\": 2481, \"text_sha256\": \"9767ed0c1022cee4fb74a2caef80b8ac9afd40077da8b6d1651fe0e631fde136\"}\n[sil-p15289213] Sildenafil increased exercise capacity during hypoxia at low altitudes and at Mount Everest base camp: a randomized, double-blind, placebo-controlled crossover trial. 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