Acute appetite and eating behaviour responses to apparatus-free, high-intensity intermittent exercise in inactive women with excess weight.

High-intensity intermittent exercise (HIIE) has been shown to transiently suppress appetite, but such exercise has traditionally required the use of specialist apparatus (e.g., cycle ergometer). This study aimed to determine appetite and eating behaviour responses to acute apparatus-free HIIE in inactive women with excess weight. A preliminary study (n = 18 inactive women, 9 healthy weight, 18.0-24.9 kg∙m; 9 with excess weight, 25.0-34.9 kg∙m) revealed that intervals of 30 s of "all out" star jumping elicited physiological responses akin to intervals of 30 s of "all out" cycling. Twelve women (29.2 ± 2.9kg∙m, 38 ± 7years, 28 ± 39 min MVPA∙week) then completed three trials in a within-subject, randomised cross-over design: 4 × 30 s "all out" star jumping (4 × 30 s); 2 × 30 s "all out" star jumping (2 × 30 s); resting control (CONT). Upon completing each late-morning exercise trial, lunch was provided upon request from the participant. The time from the exercise bout to lunch request - termed eating latency - was recorded, and ad libitum food intake at lunch was measured. Subjective appetite was measured using a visual analogue scale before and after exercise, and at lunch request. Free-living energy intake (EI) and energy expenditure (EE) were recorded for the remainder of the trial day and the three days following. Change-from-baseline in subjective appetite was significantly lower immediately after 4 × 30 s (-9.6 ± 18.4 mm) and 2 × 30 s (-11.5 ± 21.2 mm) vs. CONT (+8.1 ± 9.6 mm), (both p < 0.05, d = 0.905 and 1.027, respectively). Eating latency (4 × 30 s: 32 ± 33 min, 2 × 30 s: 31 ± 26 min, CONT: 27 ± 23 min, p = 0.843; η = 0.017) and lunch EI (4 × 30 s: 662±178 kcal, 2 × 30 sec: 715 ± 237 kcal, CONT: 726 ± 268 kcal, p = 0.451; η = 0.077) did not differ significantly between conditions. No significant differences were observed in trial day EI and EE, or in EI and EE on the three days following exercise (all p > 0.05). Mean trial day relative EI (EI - EE) was 201 ± 370 kcal lower after 4 × 30 s than CONT, but this difference was not statistically significant (p = 0.303, d = 0.585). In conclusion, very low-volume star jumping elicited a transient suppression of appetite without altering eating behaviour. (313 words).