Acute psycho-physiological responses to perceptually regulated hypoxic and normoxic interval walks in overweight-to-obese adults

Objectives We investigated psycho-physiological responses to perceptually regulated interval walks in hypoxia versus normoxia in obese individuals. Design Within-participants repeated measures. Methods Ten obese adults (BMI=32±3kg/m−2) completed a 60-min interval session (15×2min walking at a rating of perceived exertion of 14 on the 6–20 Borg scale with 2min of rest) either in hypoxia (FiO2 =13.0%, HYP) or normoxia (NOR). A third trial replicating the HYP speed pattern was carried out in normoxia as a control (CON). Exercise responses were analysed comparing the average of 1st to 3rd exercise bouts to those of the 4th–6th, 7th–9th, 10th–12th and 13th–15th exercise bouts (block 1 versus 2, 3, 4 and 5). Results Treadmill speed was slower during block 4 (6.14±0.67 versus 6.24±0.73km/h−1) and block 5 (6.12±0.64 versus 6.25±0.75km/h−1) in HYP compared to NOR or CON (p=0.009). Compared to NOR and CON, heart rate was +6–10% higher (p=0.001), whilst arterial oxygen saturation (−12–13%) was lower (p