Changes in pain perception during pregnancy after one-time maximal physical exertion and an 8-week high-intensity interval training
Question
Do a one-time maximal progressive cardiopulmonary exercise test and an 8-week high-intensity interval training program alter objective and subjective pain perception in pregnant women?
Summary
This single-arm study followed pregnant women with uncomplicated singleton pregnancies through an 8-week online HIIT program. The study measured pressure pain threshold, pressure pain tolerance, and subjective pain before and after a maximal cycling test and before and after the training program. Pain tolerance increased after the acute maximal exercise test and after the 8-week HIIT intervention, while pain threshold did not improve. The authors reported no observed adverse effects on pregnancy development, delivery, or neonatal conditions.
Methodology
- Thirty-five women with singleton, uncomplicated pregnancies between 13 and 28 weeks of gestation entered an 8-week online HIIT program.
- 35 participants.
- Online bodyweight exercise.
- Work intervals: 30-45 seconds during high-intensity interval portion.
- Recovery: 15-60 seconds depending on week, ability, pregnancy stage, and progress.
- Intensity: Expected to exceed individually determined anaerobic threshold; monitored with heart rate, Borg 0-10 RPE, and Talk Test.
- Approximately 47-60 minutes including warm-up, 15-20 minute interval block, accessory exercises, and cool-down.
- Three online classes per week.
- 8 weeks.
- Single-arm pre-post intervention study with repeated pain measurements before and after acute maximal CPET and before and after an 8-week online HIIT program.
- Pressure pain threshold, Pressure pain tolerance, Subjective pain perception, and Obstetric safety observations were tracked.
Outcomes
Pressure pain threshold
HIIT did not significantly affect pain pressure threshold; CPET effect was only marginal and in the direction of lower threshold after exercise.
PPT HIIT beta = -.11, SE = .08, t = -1.41, p = .159; CPET beta = -.15, SE = .08, t = -1.88, p = .061.
Pressure pain tolerance
Pain tolerance increased significantly after both CPET and the 8-week HIIT intervention, with the authors describing the HIIT effect as stronger.
PTOL HIIT beta = .43, SE = .06, t = 7.09, p = .001; CPET beta = .16, SE = .06, t = 2.55, p = .011; marginal R2 = 10.57%.
Subjective pain
Subjective pain experience was higher after HIIT; CPET did not significantly affect subjective pain overall.
VAS HIIT beta = .31, SE = .06, t = 5.22, p = .001; CPET beta = -.03, SE = .06, t = -0.52, p = .600; marginal R2 = 5.22%.
Safety
The authors stated they observed no adverse effects on pregnancy development, delivery, or neonatal conditions.
Insights
- Prenatal HIIT in this study was not just intervals; it included screening, online specialist supervision, warm-up, breathing/posture instruction, pelvic floor work, and relaxation.
- For uncomplicated pregnancies with obstetric clearance, bodyweight HIIT can be structured with short intervals and flexible work/rest ratios.
- The evidence is safety-sensitive and should be framed as preliminary because the study lacked a no-exercise or moderate-intensity comparison group.
Limitations
- Single-arm design with no inactive or moderate-intensity comparison group.
- Small sample.
- Only uncomplicated singleton pregnancies were included.
- One participant did not complete the program.
- Attendance and actual achieved training intensity were not reported.
- Pain was assessed at limited timepoints, with no postpartum follow-up.
Safety
- No adverse effects of the HIIT intervention on pregnancy development, delivery, or neonatal conditions were observed by the authors.
- The study excluded multiple pregnancies and contraindications to increased exertion.
- Obstetric care provider consent was required.