Vigorous physical activity could improve glucose levels in young women
Engaging in vigorous physical activity for 75 minutes or more per week could reduce glucose levels in women trying to conceive, a recent study from Singapore showed. However, this impact was not demonstrated in women who engaged in moderate physical activity for 150 minutes or more per week.
“Our findings show that engaging in vigorous physical activity may … provide beneficial effects on glucose metabolism in Asian women of reproductive age,” said the researchers.
The study involved 946 Singaporean women (mean age 31.4 years, 72 percent Chinese, mean BMI 23.8 kg/m2) enrolled in the S-PRESTO* cohort which comprised women planning to conceive within 1 year of study recruitment. Fasting blood glucose levels and glucose levels 30 and 120 minutes after a 75-g oral glucose tolerance test (OGTT) were obtained (mean, 4.8, 8.3, and 6.0 mmol/L, respectively). Physical activity levels – frequency and duration per week – were ascertained from the short form of the International Physical Activity Questionnaire (IPAQ), while watching television or screen-viewing time were substitutes for sedentary time.
About 68 percent of women were considered “insufficiently active”, 35.2 percent spent ≥2 hours/day watching television, and 23.8 percent used electronic devices for ≥3 hours/day.
After adjusting for age, ethnicity, BMI, education level, occupational status, parity, family history of diabetes, and personal history of gestational diabetes, smoking, and physical activity, women who clocked in ≥75 min/week of vigorous physical activity had lower blood glucose levels than those who did not participate in vigorous physical activity, be it fasting glucose (mean, -0.14, 95 percent confidence interval [CI], -0.28 to -0.01 mmol/L), 30-minutes post-OGTT (-0.35, 95 percent CI, -0.68 to -0.02 mmol/L), or 120-minutes post-OGTT (-0.53, 95 percent CI, -0.90 to -0.16; poverall=0.02). [Diabet Med 2019;doi:10.1111/dme.13948]
This reduction in glucose levels did not occur among women who had ≥150 minutes/week of moderate physical activity (-0.04, 95 percent CI, -0.15 to 0.08 mmol/L [fasting glucose], 0.06, 95 percent CI, -0.23 to 0.34 mmol/L [30-minutes post-OGTT], and 0.05, 95 percent CI, -0.26 to 0.37 mmol/L [120-minutes post-OGTT]; poverall=0.77) compared with women with no moderate physical activity.
Watching television for ≥2 hours/day did not appear to be associated with glucose levels (0.06, -0.04, and 0.24 mmol/L for fasting, 30-, and 120-minutes post-OGTT, respectively), nor did use of electronic devices for ≥3 hours/day (0.02, 0.24, and 0.23 mmol/L, respectively).
“Engaging in vigorous, but not in moderate, physical activity was associated with lower glucose levels at fasting, 30 minutes, and 120 minutes. Conversely, times spent watching television and using mobile electronic devices were not associated with glucose levels,” said the researchers.
“[These findings] suggest that, in the absence of any vigorous physical activity, attempting to reduce screen time alone would not be protective against hyperglycaemia,” they said.
Poor glucose metabolism during pregnancy results in gestational diabetes and leads to negative outcomes for both the pregnant woman and child, said the researchers. As such, the reductions in fasting and postprandial glucose levels in this study, while modest, could have an impact during pregnancy and child development, they said.
“Engaging weekly in vigorous physical activity of ≥75 minutes represents an achievable and suitable modifiable factor to improve glucose metabolism in women planning a pregnancy, with potential implications for the health of the next generation.”
The lack of effect of screen time on glucose levels may have been due to television watching and electronic device use being poor representations of sedentary behaviour in this population, particularly electronic device use which can be used in non-sedentary situations, added the researchers. They also acknowledged that participants’ self-reporting of screen time and physical activity, as well as lack of data on snack consumption could have affected the results.