The effect of hypoxia on exercise tolerance in individuals after acute coronary syndrome treated with angioplasty combined with coronary stent implantation – pilot studies

Background. Currently, there is little documented research evaluating the effect of a high-mountain environment on patients with ischemic heart disease. Objectives. The main aim of the study was to assess the effect of normobaric hypoxia on exercise tolerance in patients diagnosed with stable coronary disease. Material and methods. 22 men aged 37 to 72 (55.68 ± 9.86 years of age) with coronary disease were qualified. In the pre-study, in a normobaric normoxia environment, each patient underwent: resting ECG, spiroergometric test using a treadmill, laboratory tests (gasometry, lactic acid concentration). The patients stayed in the cabinet for 3 hours at the: 1) normoxia, 2) hypoxia (2000 m a.s.l), 3) hypoxia (3000 m a.s.l.) levels. After the 3-hour period, patients underwent a spiroergometric exercise tolerance test combined with a blood lactic acid concentration test. Venous blood and capillary blood were drawn for gasometry testing purposes. Results. Under 2000 and 3000 m hypoxia noted a significantly shorter duration of the exercise test, distance travelled and MET values. An increase in resting blood pH and a decrease of resting and peak pCO2 and pO2 were observed. Conclusions. As a result of a 3-hour exposure to normobaric hypoxia, the exercise tolerance of patients after acute coronary syndrome treated with angioplasty combined with coronary stent implantation decreases. There is no clear information for patients as to whether high mountain conditions are safe for them. The presented research was a form of introduction to wider and more thorough experiments that can result in practical information for patients.