PMID 32050648

Research
All papers

Affective and Enjoyment Responses to Short-Term High-Intensity Interval Training with Low-Carbohydrate Diet in Overweight Young Women

Kong Z, Hu M, Liu Y, Shi Q, Zou L, Sun S, Zhang H, Nie J

Question

How do affective and enjoyment responses to very brief all-out cycling HIIT compare with moderate-intensity continuous cycling during a 4-week low-carbohydrate diet in overweight young women?

Summary

This randomized 4-week trial studied 43 overweight young women completing a low-carbohydrate diet alone, low-carbohydrate diet plus very brief all-out cycling HIIT, or low-carbohydrate diet plus moderate continuous cycling. The HIIT protocol used 10 by 6-second all-out sprints with 9-second rests, 5 sessions per week, for only 50 minutes total training time across the intervention. Both exercise groups improved cardiorespiratory fitness while all groups lost more than 2.5 kg body weight. Affective valence and arousal were similar after HIIT and MICT, but PACES enjoyment scores favored MICT; the authors interpreted HIIT with low-carbohydrate dieting as time-efficient but more arduous and potentially less enjoyable.

Methodology

  • Overweight/obese young women using Asian BMI cutoff of at least 23 kg/m2.
  • 43 participants.
  • All-out cycling sprints.
  • Work intervals: 6 seconds all-out cycling.
  • Recovery: 9 seconds rest.
  • Intensity: All-out; achieved mean 82 +/- 4% HRmax, 68 +/- 5% HRR, RPE 4 +/- 1, mean power 249 +/- 34 W.
  • 2.5 minutes.
  • 5 sessions per week.
  • 4 weeks.
  • Randomized three-group parallel intervention with low-carbohydrate diet control, HIIT plus low-carbohydrate diet, and MICT plus low-carbohydrate diet arms.
  • Feeling Scale, Felt Arousal Scale, Exercise Enjoyment Scale, and Physical Activity Enjoyment Scale were tracked.

Outcomes

Body weight

All three low-carbohydrate diet groups reduced body weight by more than 2.5 kg.

Abstract summary; exact post values not extracted from main text.

Improved

VO2peak

Both exercise groups improved VO2peak by about 15%, while the abstract states exercise had additive cardiorespiratory fitness benefit beyond low-carbohydrate dieting.

Approximately 15% improvement reported in abstract.

Improved

Affective valence and arousal

FS scores did not differ within or between exercise groups, and FAS increased after both HIIT and MICT without significant group difference.

FS p>0.05; FAS post-exercise increases p<0.05.

No clear change

Perceived exertion

HIIT produced higher RPE than MICT at all measured weeks.

HIIT 4.5-5.3 versus MICT 1.6-2.1, p<0.01.

Safety concern

Exercise enjoyment

EES was mostly similar between groups, but PACES scores were significantly higher in MICT than HIIT across all 4 weeks.

PACES group effect F=3.422, p=0.033, eta2=0.120; abstract reports HIIT 73-78 points versus MICT 83-87 points.

Mixed

Insights

  • Very brief all-out cycling HIIT can be time-efficient and still produce generally positive immediate affect during low-carbohydrate dieting.
  • Enjoyment depends on measurement choice; quick single-item enjoyment was similar, while broader PACES enjoyment favored MICT.
  • Low-carbohydrate dieting may make all-out HIIT feel more arduous, which matters for adherence-oriented programming.
  • This protocol is best treated as an equipment-based sprint option, not direct bodyweight HIIT evidence.

Limitations

  • Short 4-week duration.
  • Small final group sizes after exclusions.
  • Study was not registered in advance.
  • Female-only overweight/obese young adult sample.
  • Low-carbohydrate diet co-intervention limits isolation of exercise-only affect responses.
  • Full inclusion and exclusion criteria were referenced to a previous study rather than restated.

Safety

  • The article did not report adverse events in the results.
  • Participants completed PAR-Q and were supervised during exercise sessions.
  • The HIIT protocol was all-out and produced higher RPE than MICT.