TV time, physical activity, sedentary behaviour and cardiometabolic biomarkers in pregnancy-NHANES 2003-2006.

OBJECTIVES: This study examined the impacts of individual and combined associations between moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) (accelerometer-derived), as well as MVPA and television (TV) time (self-reported) on cardiometabolic biomarkers during pregnancy. METHODS: Participants were 332 pregnant women from the 2003-2006 cycles of the National Health and Nutrition Examination Survey (NHANES). Multiple linear regression models were conducted to examine the relationships between individual and combinations of high/low MVPA, ST, and TV time with cardiometabolic biomarkers: body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein cholesterol (HDL), and C-reactive protein (CRP). RESULTS: Women with high MVPA (≥ 17 min/day) compared to those with low MVPA (< 17 min/day) had significantly lower BMI. Women with low ST (< 503 min/day) compared to those with high ST (≥ 503 min/day) had significantly lower SBP and DBP. Women with low TV (< 3 h/day) compared to those with high TV (≥ 3 h/day) had significantly lower BMI and log-transformed CRP. Women with a combination of low ST/high MVPA had lower SBP and DBP (ptrend < 0.03). Women with a combination of low TV/high MVPA had lower BMI and log-transformed CRP (ptrend < 0.00). CONCLUSION: We need to consider both physical activity and sedentary time for improved cardiometabolic health during pregnancy.

RéSUMé: OBJECTIFS: Notre étude porte sur les effets des associations individuelles et combinées entre l'activité physique modérée à vigoureuse (APMV) et le temps de sédentarité (TS) (mesuré par accéléromètre), ainsi qu'entre l'APMV et le temps de télévision (TT) (autodéclaré) et les biomarqueurs cardiométaboliques durant la grossesse. MéTHODE: Les participantes étaient 332 femmes enceintes ayant participé aux cycles 2003­2006 de la National Health and Nutrition Examination Survey (NHANES). Des modèles de régression linéaire multiple ont été appliqués aux liens individuels et combinés entre l'APMV, le TS et le TT élevés/faibles et les biomarqueurs cardiométaboliques suivants : indice de masse corporelle (IMC), pression systolique (PS), pression diastolique (PD), cholestérol à lipoprotéines de haute densité (HDL) et protéine C réactive (CRP). RéSULTATS: L'IMC était significativement plus faible chez les femmes dont l'APMV était élevée (≥ 17 min/j) que chez celles dont l'APMV était faible (< 17 min/j). La PS et la PD étaient significativement plus faibles chez les femmes dont le TS était faible (< 503 min/j) que chez celles dont le TS était élevé (≥ 503 min/j). L'IMC et la protéine CRP log-transformée étaient significativement plus faibles chez les femmes dont le TT était faible (< 3 h/j) que chez celles dont le TT était élevé (≥ 3 h/j). La PS et la PD étaient plus faibles (ptendance < 0,03) chez les femmes qui présentaient une combinaison de TS faible et d'APMV élevée. Et l'IMC et la protéine CRP log-transformée étaient plus faibles (ptendance < 0,00) chez les femmes qui présentaient une combinaison de TT faible et d'APMV élevée. CONCLUSION: Il faut tenir compte à la fois de l'activité physique et du temps de sédentarité pour améliorer la santé cardiométabolique durant la grossesse.

Peripheral chemoreceptor deactivation attenuates the sympathetic response to glucose ingestion.

Acute increases in blood glucose are associated with heightened muscle sympathetic nerve activity (MSNA). Animal studies have implicated a role for peripheral chemoreceptors in this response, but this has not been examined in humans. Heart rate, cardiac output (CO), mean arterial pressure, total peripheral conductance, and blood glucose concentrations were collected in 11 participants. MSNA was recorded in a subset of 5 participants via microneurography. Participants came to the lab on 2 separate days (i.e., 1 control and 1 experimental day). On both days, participants ingested 75 g of glucose following baseline measurements. On the experimental day, participants breathed 100% oxygen for 3 min at baseline and again at 20, 40, and 60 min after glucose ingestion to deactivate peripheral chemoreceptors. Supplemental oxygen was not given to participants on the control day. There was a main effect of time on blood glucose (P < 0.001), heart rate (P < 0.001), CO (P < 0.001), sympathetic burst frequency (P < 0.001), burst incidence (P = 0.01), and total MSNA (P = 0.001) for both days. Blood glucose concentrations and burst frequency were positively correlated on the control day (r = 0.42; P = 0.03) and experimental day (r = 0.62; P = 0.003). There was a time × condition interaction (i.e., normoxia vs. hyperoxia) on burst frequency, in which hyperoxia significantly blunted burst frequency at 20 and 60 min after glucose ingestion only. Given that hyperoxia blunted burst frequency only during hyperglycemia, our results suggest that the peripheral chemoreceptors are involved in activating MSNA after glucose ingestion.