What effect does short-term moderate hypoxia exposure during constant workload exercise have on post exposure measurements of resting substrate partitioning?

摘要

Recent studies have shown a potentiation effect of exercise performed under moderateudshort-term hypoxia on weight loss. From these data, it has been hypothesized thatudmoderate hypoxia exposure affects substrate utilization and that normobaric hypoxiaudtraining might be an effective means to induce weight loss. However, limited data isudcurrently available on resting substrate partitioning after a single bout of exerciseudperformed under hypoxia. The purpose of the current study was therefore to asses theudviability of moderate short-term hypoxia exposure during constant workload exercise as audmeans to alter post exposure resting substrate partitioning. Respirometry measurementsudwere recorded at baseline (BMRpre), during 60-min constant workload exercise (underudnormoxia N-CWE; and hypoxia H-CWE ) and during post exposure resting metabolicudmeasurements; recorded immediately after exercise (PEMR, 0-60-min) and again the nextudmorning (BMRpost). Compared to baseline, lipid oxidation was significantly elevated andudcarbohydrate oxidation suppressed during PEMR (p=0.010 and p=0.076, respectively)udand BMRpost (p=0.036 and p=0.010, respectively) after H-CWE. When the sameudabsolute workload was performed under normoxia, no effect on resting substrateudpartitioning was observed during the post exercise recording periods. An increasedudreliance on endogenous carbohydrate sources during H-CWE compared to N-CWE isudsuggested to explain the current findings. In conclusion, a single bout of exerciseudperformed under moderate short-term hypoxia is associated with a shift in restingudsubstrate partitioning toward an increased lipid oxidation up to 22-hr post exposure.