How does maternity yoga reduce stress and improve sleep during pregnancy?
Research Study At A Glance
Research Study At A Glance
The Research Question Asked
How does yoga affect stress levels and sleep during the second and third trimester of pregnancy? Can maternity yoga reduce stress?
Type of Study
Longitudinal study with matched treatment and control groups (a type of study which follows a group of participants over time)
Study Participants (Sample)
Sample size: 38 women in yoga treatment group; 53 women in control group
- 91 total women
- All began study participation between weeks 20-23 of their pregnancy
- Healthy: no physical health issues
The yoga treatment group of study participants attended a maternity yoga class once per week and were encouraged to do 15 minutes of daily yoga practice at home the rest of the week. Both the yoga treatment group and the control group were evaluated for physiological measurements of stress level (heart rate variability and alpha-amylase levels in saliva) and completed the perceived stress scale questionnaire to assess perceived stress levels. Sleep patterns were assessed by having participants complete a sleep log.
There was an increase in heart rate variability and a reduction in alpha amylase during several periods of the study for those in the yoga treatment group compared to those in the control group. Both indicate that physiologically, yoga reduced stress. Additionally, sleep time was higher and the number of nighttime awakenings was lower (both indicators of better sleep) during several periods of the study for those in the yoga treatment group compared to those in the control group.
Yoga reduced stress and improved sleep during the second and third trimester of pregnancy.
As we’ve highlighted in a previous article, researchers have reported that one of the mechanisms of yoga, or ways that yoga works, is through balancing the activity of the sympathetic and parasympathetic nervous systems. Maintaining the right balance between the activity of these two parts of the nervous system is important for mediating the effects of stress on the body and helping us sleep. As pregnancy can affect stress levels and impact sleep, researchers were interested in whether a maternity yoga class could reduce the effects of stress during pregnancy and help improve sleep, particularly during the second and third trimester.
How does yoga affect stress levels and sleep during the second and third trimester of pregnancy?
All participants began the study between weeks 20 and 23 of their pregnancy. The study was a longitudinal study (a type of study which follows a group of participants over time) which ran from January 2013 to December 2014. A group of 38 women formed the yoga treatment group and attended yoga classes once per week for 60 minutes. Each yoga class included asanas, breathing practices, and a 10-minute meditation. It was recommended to participants in the yoga treatment group that they also do a daily home yoga practice for 15 minutes each day. The control group of 53 women did not participate in the yoga classes or the home yoga practice.
Two physiological indicators of stress levels were measured: heart rate variability and alpha-amylase levels. Heart rate variability was calculated for all study participants for four time frames: morning, afternoon, night, and late night. Participants provided saliva samples that were tested for alpha-amylase at 20-23 weeks, 28-31 weeks, and 36-40 weeks into their pregnancy. Participants also completed the perceived stress scale questionnaire which is designed to record self-reported stress levels. In order to evaluate yoga’s effect on sleep, participants were asked to keep a sleep log for seven days.
Multiple indicators suggested that yoga did reduce stress levels compared to the control group. Heart rate variability was higher in the yoga treatment group than the control group during the night and late night periods at 28-31 weeks of pregnancy. At 36-40 weeks of pregnancy, heart rate variability was higher in the yoga treatment group in the morning, afternoon, and late night periods. The measurement of alpha-amylase was lower after doing yoga than before yoga at all weeks. There were no statistical differences between the yoga treatment group and the control group in the results of the perceived stress scale questionnaire, which measured self-assessed stress levels.
There were also differences in sleep patterns between the yoga treatment group and the control group. Sleep time at night was higher in the yoga treatment group at 28-31 weeks and 36-40 weeks. The frequency of nighttime awakenings was lower in the yoga treatment group at 28-31 weeks and 36-40 weeks. There was also a positive correlation between the number of yoga classes attended by study participants and their nighttime sleep time.
Why is this relevant to yoga practitioners?
Many yoga practitioners are aware of feeling less stressed and sleeping better when they are consistent with their yoga practice. This research supports the idea that yoga practice can be modified for different phases of life and still provide important wellness benefits. Life changes of all kinds, including pregnancy, can add some amount of stress to our life. This research supports the idea that yoga can reduce stress during these times of change.
Hayase, M. and M. Shimada. 2018. Effects of maternity yoga on the autonomic nervous system during pregnancy. The Journal of Obstetrics and Gynaecology Research. 44(10):1887-1895.