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A new interesting article has been published in J Sports Sci. 2019 Jul;37(14):1638-1647. doi: 10.1080/02640414.2019.1580130. Epub 2019 Feb 16. and titled:

Combined effects of exposure to hypoxia and cool on walking economy and muscle oxygenation profiles at tibialis anterior.

Authors of this article are:

Horiuchi M, Handa-Kirihara Y, Abe D, Fukuoka Y.

A summary of the article is shown below:

We investigated combined effects of ambient temperature (23°C or 13°C) and fraction of inspired oxygen (21%O2 or 13%O2) on energy cost of walking (Cw: J·kg-1·km-1) and economical speed (ES). Eighteen healthy young adults (11 males, seven females) walked at seven speeds from 0.67 to 1.67 m s-1 (four min per stage). Environmental conditions were set; thermoneutral (N: 23°C) with normoxia (N: 21%O2) = NN; 23°C (N) with hypoxia (H: 13%O2) = NH; cool (C: 13°C) with 21%O2 (N) = CN, and 13°C (C) with 13%O2 (H) = CH. Muscle deoxygenation (HHb) and tissue O2 saturation (StO2) were measured at tibialis anterior. We found a significantly slower ES in NH (1.289 ± 0.091 m s-1) and CH (1.275 ± 0.099 m s-1) than in NN (1.334 ± 0.112 m s-1) and CN (1.332 ± 0.104 m s-1). Changes in HHb and StO2 were related to the ES. These results suggested that the combined effects (exposure to hypoxia and cool) is nearly equal to exposure to hypoxia and cool individually. Specifically, acute moderate hypoxia slowed the ES by approx. 4%, but acute cool environment did not affect the ES. Further, HHb and StO2 may partly account for an individual ES.

Check out the article’s website on Pubmed for more information:

This article is a good source of information and a good way to become familiar with topics such as: Adaptation, Physiological;Adult;Exercise Test;Female;Heart Rate;Humans;Male;Muscle, Skeletal;Oxygen;Pulmonary Gas Exchange;Skin Temperature;Walking Speed;Young Adult.