Altitude and the Heart: Is Going High Safe for Your Cardiac Patient?

John P. Higgins, MD, MPhil; Troy Tuttle, MS; Johanna A. Higgins, MD

Disclosures

Am Heart J 

In This Article

Abstract and Introduction

Abstract

Our aging population combined with the ease of travel and the interest in high altitude recreation pursuits exposes more patients to the acute physiologic effects of high altitude and lower oxygen availability. Acute exposure to high altitude is associated with significant alterations to the cardiovascular system. These may be important in patients with underlying cardiovascular disease who are not able to compensate to such physiologic changes. Exacerbating factors pertinent to patients with cardiovascular disease include acute hypoxia, increased myocardial work, increased epinephrine release, and increased pulmonary artery pressures. This review summarizes the physiology and clinical evidence regarding acute altitude exposure on the cardiopulmonary system with practical recommendations to address the question: "Is it safe for me to ski in the Rockies or climb Mt. Kilimanjaro?"

Introduction

More than 100 million people travel to high altitudes annually, which place some at risk for complications involving the acute effects of hypobaric hypoxia.[1] High altitude trekking and recreational activities provide a unique physiologic challenge to the cardiopulmonary system.[2,3] Often, people are acutely exposed to high altitude for 4 to 6 hours for specific recreational activities, and thus, there is limited time for physiologic adaptations to occur.[4] Environmental changes when moving from sea level to altitude include reductions in atmospheric pressure, oxygen pressure, humidity, and temperature.[5] The exact altitude at which physiologic changes affect health and cardiopulmonary performance is not constant, but significant changes typically begin at > 2,500 m (8,200 ft).[6] At this moderate altitude, the partial pressure of oxygen in the arterial blood is about 60 mm Hg, compared with 98 mm Hg at sea level.[7] The degree to which changes occur depend on the change in elevation, degree of hypoxia, rate of ascent, level of acclimatization, exercise intensity, genetics, and age.[5,8,9] For the purpose of this review, low altitude is considered to range from sea-level to 1,500 m (4,950 ft), moderate altitude from 1,500-2,500 m (4,950-8,250 ft), and high altitude > 2500 m (8,250 ft).

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