ABSTRACT
Intermittent hypoxia is observed in many clinical situations. During early develop-
ment, hypoxia is frequently externally imposed in an intermittent pattern.
Environmental, rather than endogenous, factors during early life including the
‘‘in utero’’ environment may have great consequences during later life. During
both the pre-and postnatal periods the supply of oxygen is an important com-
ponent of overall energy balance. Hypoxia may also be compounded by envi-
ronmental toxins such as nicotine in cigarette smoke. Cigarette smoke is an
important environmental toxin and significant health effects have been demon-
strated in infants exposed to cigarette smoke during the pre-and/or the postnatal
period. In the postnatal period, new environmental factors such as sleeping in the
prone sleep position become relevant. Throughout life, the most common
example of a disease resulting in intermittent hypoxia is obstructive sleep apnea
(OSA), which in children is most commonly associated with adenotonsillar
enlargement.
