Mountain sport activities as for example hiking or skiing may involve the risk of adverse health events especially in older people not accustomed to the specific mountain sport at altitude or people with pre-existing health issues. Increased activation of the sympathetic nervous system and abrupt changes in heart rate and blood pressure are thought to trigger these adverse effects. Preventive measures include regular physical activity (i.e. training) and adequate medical treatment. Hypoxia pre-adaptation (e.g., pre-adapt one night at moderate altitude) and pre-conditioning (e.g., intermittent hypoxia (IH) training), which was shown to lead to some favorable sympathetic nervous system, ventilatory and metabolic adaptations and additionally exerts anti-inflammatory action, could be hypothesized of being a further preventive measure. The aim of this research project is to investigate whether intermittent hypoxia pre-conditioning or sleeping one night at altitude (i.e., current recommendation before practicing mountain leisure sports in the elderly) is able to increase oxygen saturation during passive hypoxia exposure and during simulated hiking and skiing at altitude. Additionally, it is aimed to investigate whether such procedure reduces the physiological responses (i.e., heart rate, its variability and blood pressure (including baroreflex sensitivity) responses as well as metabolic, ventilatory, inflammatory and redox responses) during these activities.

Inclusion Criteria:

• Participants will include normally physically active males and females (age 50-70 years; New York Heart Association (NYHA) class I and II) with or without prior myocardial infarction, living <600 m.

Exclusion Criteria:

• Persons with CAD will be excluded if they will not be able to perform light to moderate exercise, or had recent myocardial infarction and/or revascularisation (< 8 weeks prior to inclusion in the study), episode of unstable angina, de-compensated heart failure, life-threatening arrhythmia, ejection fraction < 50%, known symptomatic aortic outflow obstruction, severe hypertension (>180/100 mm Hg), pulmonary hypertension or any other severe systemic non-cardiac disease. Exclusion criteria will additionally include regular smoking of more than five cigarettes per day, regular drug intake, habitual residence > 600 m and one or more overnight stay at > 1000 m during the previous 4 weeks.

Data underlying scientific publications will be stored in open repositories (accessible).

After publications

The data that support the findings of this study are available from the corresponding author upon reasonable request.