Can we hit prenatal depression and anxiety through HIIT? The effectiveness of online high intensity interval training in pregnant women during the COVID-19 pandemic: a randomized controlled trial

In recent years high intensity interval training (HIIT) has grown in popularity. However, it rarely represents training interventions in experimental studies in pregnant populations. Therefore, in this study we aimed to assess changes in depressive symptoms, fear of childbirth, fear of Covid-19 and quality of life after an 8-week supervised online HIIT program, compared to an educational (self-performed physical activity) program. We conducted a randomized control trial among 54 Caucasian women in uncomplicated, singleton pregnancy (age 32 ± 4 years, 22 ± 4 week of gestation; mean ± SD). There were 34 women in the experimental group, who participated in an 8-week high intensity interval training program (HIIT group). The comparative group was constituted of 20 pregnant women who attended 8-week educational program (EDU group). The most important finding was that mental health improved somewhat in both groups after the intervention, but only the HIIT group improved statistically significantly. The positive trends in lowering the severity of depressive symptoms, fear of childbirth, and fear of Covid-19 were observed in both groups. However, the positive response to the intervention was stronger in the EDU group. As a secondary outcome, there was a significant decrease in cardiorespiratory fitness level in the EDU group, while the HIIT group maintained unchanged level of maximal oxygen uptake. HIIT seems to be beneficial for women with uncomplicated pregnancies to maintain adequate quality of life and mental health. However, more research is needed to determine the effectiveness of prenatal HIIT in pregnant women in various psychological conditions. We conducted this study in Poland, in 2021. It was approved by the Bioethics Commission at the District Medical Chamber in Gdansk (KB-8/21). The full study protocol was registered in ClinicalTrials.gov (NCT05009433).