Brigham Research Institute Poster Session Site logo-1
Close this search box.

Jingyi Qian, PhD








Associate Physiologist




Jingyi Qian*, Qian Xiao, Michael P. Walkup, Mace Coday, Melissa L. Erickson, Jessica Unick, John M. Jakicic, Kun Hu, Frank A.J.L. Scheer, Roeland J.W. Middelbeek, and the Look AHEAD Research Group

Association of Timing of Moderate-to-Vigorous Physical Activity with Changes in Glycemic Control over 4 Years in The Look AHEAD Trial

I truly appreciate the opportunity to celebrate and highlight women scientists’ achievements. And I would love to learn from my female colleagues’ brilliant work and network with them. My research is primarily focused on the physiological mechanisms by which timing of behavior, such as physical activity, can interact with the circadian system, and synergistically affect cardiometabolic outcomes. Although my current abstract does not focus on sex difference specifically, my previous research has found that sex could modulate such interactions. Thus, I aim to gain more mechanistic insights into the sex difference in circadian physiology.


We determined the longitudinal association of time-of-day of bout-related moderate-to-vigorous physical activity (bMVPA) with changes in glycemic control across 4 years in adults with type 2 diabetes in the Look AHEAD trial.


Among 2416 participants (57% female; mean age, 59 years) with 7-day waist-worn accelerometry recording at year 1 or 4, we defined the time-varying exposure by time-of-day of bMVPA: ≥50% of bMVPA during the same time period (Morning, Midday, Afternoon, or Evening), <50% of bMVPA in any time period (Mixed), and ≤1 day with bMVPA per week (Inactive, the reference).


HbA1c reduction at year 1 varied by bMVPA timing (P=0.02), independent of bMVPA volume and intensity. The afternoon group had the greatest HbA1c reduction, the magnitude of which was 30%-50% larger than the other groups. The odds of discontinuation versus maintaining/initiating glucose-lowering medications at year 1 differed by bMVPA timing (P=0.04). The afternoon group had the highest odds (OR: 2.13 [1.29, 3.52]). For all the bMVPA timing groups, there were no significant changes in HbA1c between year 1 and 4.


bMVPA performed in the afternoon is associated with improvements in glycemic control in adults with diabetes, especially within the initial 12 months of an intervention.