Maintenance of time-restricted eating and high-intensity interval training in women with overweight/obesity 2 years after a randomized controlled trial
Question
Do women with overweight or obesity maintain TRE and/or HIIT 2 years after a supervised 7-week randomized trial, and are cardiometabolic outcomes maintained?
Summary
This 2-year follow-up of the TREHIIT randomized trial asked whether women with overweight or obesity continued time-restricted eating or HIIT after a 7-week supervised intervention. About one-third of the original HIIT group and 45% of the combined TREHIIT group still reported doing HIIT after 2 years, but cardiometabolic between-group differences were not statistically significant at the stricter threshold. Participants described HIIT as time-efficient and mastery-building, while lack of time, pain, injury, motivation, and exertion discomfort were common barriers.
Methodology
- Women with overweight or obesity from the TREHIIT trial.
- 59 participants.
- Treadmill running or stationary cycling.
- Work intervals: 4 min and 1 min intervals.
- Recovery: 3 min active recovery or 1 min low-intensity standing/walking.
- Intensity: 90-95% HRmax or maximum sustainable 1-min intensity.
- 3 sessions/week.
- 7 weeks.
- Two-year follow-up of a randomized controlled trial, analyzed by original group assignment.
- HIIT continuation, Body composition, VO2peak, and Cardiometabolic blood markers were tracked.
Outcomes
HIIT maintenance
4/12 original HIIT participants and 9/20 TREHIIT participants still reported undertaking HIIT after 2 years.
HIIT 33%; TREHIIT 45%.
Cardiometabolic between-group outcomes
No statistically significant between-group differences at p<0.01 after 2 years.
Non-significant body mass HIIT vs CON p=0.019 and visceral fat TREHIIT vs CON p=0.015.
Within-group body composition and fitness
HIIT and TREHIIT had lower body mass, fat mass, and visceral fat area and higher VO2peak versus baseline at 2 years.
HIIT fat mass -4.2 kg p<0.001; visceral fat -19 cm2 p<0.001; VO2peak +2.7 mL/kg/min p=0.002.
Experience and barriers
HIIT was rated favorably and valued for time-efficiency/mastery, but lack of time, injury, pain, motivation, difficulty, and exertion discomfort were barriers.
HIIT rating 7.5 (2.1)/10.
Insights
- A short supervised HIIT block may seed longer-term exercise habits for some users.
- Long-term adherence support should address time, injury/pain, motivation, and exertion discomfort.
- Adding exercise variety may help people who enjoy HIIT but do not want only HIIT.
Limitations
- Only a subset attended 2-year follow-up
- Self-selection bias
- Recall bias from self-reported continuation
- No objective adherence or interim physical activity data
- Limited power and multiple comparisons
Safety
- Injury and pain were reported as barriers to maintaining HIIT.
- No formal adverse-event count was reported in this follow-up article.