Interval hypoxia-hyperoxia training effective for improving cardiorespiratory fitness
Interval hypoxia-hyperoxia training (IHHT) is effective for improving cardiopulmonary fitness and quality of life (QoL) in elderly patients with coronary artery disease (CAD), according to data presented at the Singapore Prevention & Cardiac Rehabilitation Symposium (SPCRS) 2017.
Forty-six patients were randomized to undergo IHHT (thrice-weekly sessions, n=27) or a standard cardiac rehabilitation programme consisting of sham hypoxic training using a normobaric normoxic mixture (15 sessions, n=19) for 5 weeks. Participants were evaluated at baseline using a 10-minute continuous hypoxia test with 10 percent oxygen (O2) to customize the IHHT protocol and evaluate individual responses to hypoxia. [SPCRS 2017, abstract O-45]
At baseline, those who received standard treatment had a significantly higher cardiopulmonary fitness level vs those who underwent IHHT (1.44 litres of O2 per minute [IO2/min] vs 1.11 IO2/min).
At treatment end, cardiopulmonary fitness levels were similar in both IHHT and standard treatment groups (1.35 IO2/min vs 1.48 IO2/min).
At 1-month follow-up, IHHT outdid standard treatment with significantly improved cardiopulmonary fitness levels (p=0.043).
Additionally, IHHT participants exhibited marked improvement in terms of health-related QoL (60.5 vs 49.5; p=0.003) and psychological state (67.2 vs 59.2; p=0.02) compared with standard treatment recipients.
Apart from reports of light headache and light dizziness during the initial hypoxic-hyperoxic exposure, no major adverse effects were reported.
Cardiopulmonary fitness is an independent predictor of cardiovascular health and can offset the negative effects of metabolic syndrome, thus protecting individuals from developing chronic cardiometabolic conditions, said the researchers.
“[However], only a fraction of patients and healthy people exercise regularly,” underlined the researchers, adding that elderly patients with cardiac pathology are often sedentary, leading to poor cardiopulmonary fitness levels.
Overall, IHHT was well tolerated and effective in improving cardiopulmonary fitness, noted the researchers. However, there is limited evidence on the efficacy of IHHT, hence the need for further research to compare post-treatment outcomes to include relevant aspects such as QoL, psychological and behavioural risk factors, extended panel of cardiometabolic markers, and physical activity routines of elderly patients with CAD, they added.
“[As] a noninvasive and non-pharmacological intervention, [cardiopulmonary fitness] could be delivered by physiotherapists as an additional component in a multidisciplinary team rehab plan,” said the researchers.