1.
Intermittent Hypoxia/Hyperoxia Versus Intermittent Hypoxia/Normoxia: Comparative Study in Prediabetes.
Serebrovska, TV, Grib, ON, Portnichenko, VI, Serebrovska, ZO, Egorov, E, Shatylo, VB
High altitude medicine & biology. 2019;(4):383-391
Abstract
Background: Intermittent hypoxia/normoxia training (IHT) is considered a possible means to alleviate chronic diseases such as diabetes. In the last decade, another method of intermittent hypoxia/hyperoxia training (IHHT) began to enter the clinical practice, when the periods of breathing with atmospheric air are replaced by breathing a hyperoxic mixture. The present study compared the impact of adaptation to IHHT versus IHT on some metabolic variables in prediabetic patients. Methods: A placebo-controlled trial included 55 patients with prediabetes, sea level residents, ages 51-74 years. Control Group (16 patients) took sham 3-week course, and the IHHT Group (17 patients) and IHT Group (22 patients) received similar actual sessions of IHHT or IHT five times a week for 3 weeks, each session consisting four cycles of 5 minutes of hypoxia (12% O2) followed by 3 minutes of hyperoxia (IHHT, 33% O2) or 5 minutes of normoxia (IHT, breathing room air). Fasting glucose, oral glucose tolerance test (OGTT), blood lipids, and the level of blood oxygen saturation (SpO2) were investigated at baseline, as well as 1 day and 1 month after IHHT/IHT termination. Results: The study showed the same positive effect of two types of training: equal reduction of serum glucose concentrations, both fasting and 2 hours of OGTT; decreased total blood cholesterol and low-density lipoproteins; and an equally smaller drop in SpO2 during acute hypoxic test (breathing with 12% O2 for 20 minutes). Improved parameters persisted 1 month after training termination in both groups. Conclusion: One of the advantages of IHHT over IHT observed in this study could be some reduction in the duration of the sessions due to shortening reoxygenation periods. Further studies are required to search for additional beneficial effects of IHHT when using other training modes or other pathologies.
2.
The effects of different forms of daily exercise on metabolic function following short-term overfeeding and reduced physical activity in healthy young men: study protocol for a randomised controlled trial.
Walhin, JP, Chen, YC, Hengist, A, Bilzon, J, Betts, JA, Thompson, D
Trials. 2018;(1):199
Abstract
BACKGROUND Short-term overfeeding combined with reduced physical activity impairs metabolic function and alters the expression of key genes within adipose tissue. We have shown that daily vigorous-intensity running can prevent these changes independent of any net effect on energy imbalance. However, which type, intensity and/or duration of exercise best achieves these benefits remains to be ascertained. METHODS/DESIGN Forty-eight healthy young men will be recruited and randomly allocated to one of four experimental conditions for 1 week: (1) to ingest 50% more energy than normal by over-consuming their habitual diet whilst simultaneously restricting their physical activity below 4000 steps day-1 (i.e. energy surplus; SUR group); (2) the same regimen but with a daily 45-min bout of vigorous-intensity arm crank ergometry at 70% of maximum oxygen uptake (SUR + ARM group); (3) the same regimen but with a daily 45-min bout of moderate-intensity treadmill walking at 50% of maximum oxygen uptake (SUR + MOD group); (4) the same regimen but with the addition of intermittent short bouts of walking during waking hours (SUR + BREAKS group). Critically, all exercise groups will receive additional dietary energy intake to account for the energy expended by exercise, thus maintaining a matched energy surplus. At baseline and follow-up, fasted blood samples, abdominal subcutaneous adipose tissue and skeletal muscle biopsies will be obtained and oral glucose tolerance tests conducted. DISCUSSION This study will establish the impact of different forms of daily exercise on metabolic function at the whole-body level as well as within adipose tissue and skeletal muscle in the context of a standardised energy surplus. TRIAL REGISTRATION ISRCTN, ISRCTN18311163 . Registered on 24 June 2015.