Adaptations following an intermittent hypoxia-hyperoxia training in coronary artery disease patients: a controlled study.
BACKGROUND
Repeated exposure to intermittent normobaric hypoxia improves exercise tolerance in cardiac patients. Little is known on the effects of intermittent normobaric hypoxia-hyperoxia exposure in coronary artery disease (CAD) patients (New York Heart Association II-III).


OBJECTIVE
IHHT improves exercise tolerance, cardiometabolic profile, and quality of life in CAD patients.


METHODS
The study design was a nonrandomized, controlled, before-and-after trial. Forty-six CAD patients volunteered to take part in the study: a group of 27 patients undertook the intermittent hypoxia (O2at 10%)-hyperoxia (O2at 30%) training (IHHT), whereas a control group (CTRL) of 19 patients, who already completed an 8-week standard cardiac rehabilitation program, was allocated to sham-IHHT treatment (breathing room air, O2at 21%). Exercise performance, blood and metabolic profiles, and quality of life (Seattle Angina Questionnaire [SAQ]) were measured before and after in the IHHT group (IHHG) and sham-IHHT in the CTRL group.


RESULTS
The IHHG showed improved exercise capacity, reduced systolic and diastolic blood pressures, enhanced left ventricle ejection fraction, and reduced glycemia, but only at 1-month follow-up. Angina as a reason to stop exercising was significantly reduced after treatment and at 1-month follow-up. The IHHT SAQ profile was improved in the IHHG and not significantly different to the CTRL group after standard rehabilitation. The IHHG was also compared to the CTRL group at 1-month follow-up, and no differences were found.


CONCLUSIONS
In CAD patients, an IHHT program is associated with improved exercise tolerance, healthier risks factors profile, and a better quality of life. Our study also suggests that IHHT is as effective as an 8-week standard rehabilitation program.
I. M. Sechenov First Moscow State Medical University, Moscow, Russia.
Oleg
O
Glazachev
I. M. Sechenov First Moscow State Medical University, Moscow, Russia.
Phylipp
P
Kopylov
School of Health and Human Performance, Dublin City University, Dublin, Ireland.
Davide
D
Susta
I. M. Sechenov First Moscow State Medical University, Moscow, Russia.
Elena
E
Dudnik
I. M. Sechenov First Moscow State Medical University, Moscow, Russia.
Elena
E
Zagaynaya
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D003324:Coronary Artery Disease / Q000503:physiopathology / Q000534:rehabilitation*; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D018496:Hyperoxia; D000860:Hypoxia; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D016896:Treatment Outcome
Intermittent hypoxia-hyperoxia training, exercise tolerance, cardiometabolic profile, coronary artery disease, cardiac rehab