Effects of Maternal Exercise During Pregnancy on Offspring Body Composition and Voluntary Exercise
Authors: Schwartz Nicolas L. , Schmill Margaret P. , Cadney Marcell D. , Castro Alberto A. , Hillis David A. , McNamara Monica P. , Garland Theodore 
Published: April 2020

The Developmental Origins of Health and Disease hypothesis posits that various factors experienced early in life can predispose individuals to being healthy or unhealthy as adults. For example, children with high birth weight, either by being born to obese mothers or mothers who experience high gestational weight gain during pregnancy, are more likely to be obese as adults. Although maternal diet has been shown to affect offspring body weight in both humans and rodents, the role of maternal exercise remains unclear.We studied a novel animal model, mice from 4 replicate High Runner (HR) lines selectively bred for ~85 generations for voluntary wheel running and 4 non‐selected Control (C) lines. HR mice run ~3‐fold longer distances than C on a daily basis. In the present study, 80 female mice (prospective dams) were given wheel access starting at 12 weeks of age, paired with males after 2 weeks for a period of 18 days, and allowed continued wheel access until 10 days after giving birth. An additional 80 dams were not given wheels. Offspring body composition was measured at weaning (3 weeks of age), after sexual maturity (7 weeks of age), and after breeding (20 weeks of age for males, 24 weeks of age for females). Offspring wheel running was measured at 7 weeks of age for 6 days, as is used in the selection experiment.During the 14 days prospective dams were housed individually, and consistent with many previous studies, HR dams ran ~3‐fold more than C (HR mean = 16,215 rev/day, range = 10,898 to 21,653 revs/day; C mean = 5,478 rev/day, range = 3,338 to 8,422 revs/day, p < 0.0001). During the first 5 days after giving birth, dams ran very little (HR mean = 1,758 rev/day, range = 145 to 2,816 revs/day; C mean = 1,445 rev/day, range = 707 to 2,574 revs/day; p = 0.1519) and during days 6–10 after birth they ran even less (HR mean = 1,377 rev/day, range = 92 to 3,851 revs/day; C mean = 1,109 rev/day, range = 210 to 2,408 revs/day; p = 0.5229).Maternal wheel access did not significantly affect either time from pairing to giving birth or litter size. Maternal wheel access did not significantly affect offspring wheel‐running distance, but HR offspring ran ~2.75‐fold more than C for males (HR mean = 8,495 rev/day, range = 3,051 to 16,733 revs/day; C mean = 3,080 rev/day, range = 376 to 6,002 revs/day; p = 0.0012) and ~3‐fold more for females (HR mean = 11,448 rev/day, range = 4,316 to 21,128 revs/day; C mean = 3,703 rev/day, range = 448 to 7,894 revs/day; p = 0.0002), as expected. At 7 weeks of age (after sexual maturity), maternal wheel access had an interactive effect on female offspring (p = 0.0117), increasing lean mass for C mice but decreasing it for HR mice.Overall, our results show that although maternal wheel access during pregnancy did not alter litter size or offspring wheel‐running behavior, it did have effects on offspring body composition at sexual maturity, but the effects varied between the sexes and in relation to genetic background (linetype).