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- Alex, Christian, et al.
(författare)
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Aerobic Exercise and Strength Training Effects on Cardiovascular Sympathetic Function in Healthy Adults: A Randomized Controlled Trial
- 2013
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Ingår i: Psychosomatic Medicine. - 0033-3174. ; 75:4, s. 375-381
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Exercise has widely documented cardioprotective effects, but the mechanisms underlying these effects are not entirely known. Previously, we demonstrated that aerobic but not strength training lowered resting heart rate and increased cardiac vagal regulation, changes that were reversed by sedentary deconditioning. Here, we focus on the sympathetic nervous system and test whether aerobic training lowers levels of cardiovascular sympathetic activity in rest and that deconditioning would reverse this effect. Methods: We conducted a randomized controlled trial contrasting the effects of aerobic (A) versus strength (S) training on indices of cardiac (preejection period, or PEP) and vascular (low-frequency blood pressure variability, or LF BPV) sympathetic regulation in 149 young, healthy, and sedentary adults. Participants were studied before and after conditioning, as well as after 4 weeks of sedentary deconditioning. Results: As previously reported, aerobic capacity increased in response to conditioning and decreased after deconditioning in the aerobic, but not the strength, training group. Contrary to prediction, there was no differential effect of training on either PEP (A: mean [SD] -0.83 [7.8] milliseconds versus S: 1.47 [6.69] milliseconds) or LF BPV (A: mean [SD] -0.09 [0.93] lnmm Hg-2 versus S: 0.06 [0.79] lnmm Hg-2) (both p values >.05). Conclusions: These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on resting state cardiovascular indices of PEP and LF BPV. These results indicate that in healthy, young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in resting sympathetic activity.
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- Lindgren, Martin, et al.
(författare)
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Effects of aerobic conditioning on cardiovascular sympathetic response to and recovery from challenge
- 2013
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Ingår i: Psychophysiology. - : Wiley. - 1540-5958 .- 0048-5772. ; 50:10, s. 963-973
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Tidskriftsartikel (refereegranskat)abstract
- Exercise has widely documented cardioprotective effects, but the mechanisms behind these effects are still poorly understood. Here, we test the hypothesis that aerobic training lowers cardiovascular sympathetic responses to and speeds recovery from challenge. We conducted a randomized, controlled trial contrasting aerobic versus strength training on indices of cardiac (pre-ejection period, PEP) and vascular (low-frequency blood pressure variability, LF-BPV) sympathetic responses to and recovery from psychological and orthostatic challenge in 149 young, healthy, sedentary adults. Aerobic and strength training did not alter PEP or LF-BPV reactivity to or recovery from challenge. These findings, from a large randomized, controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on PEP and LF-BPV reactivity to or recovery from psychological or orthostatic challenge. In healthy young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in sympathetic activity. Copyright © 2013 Society for Psychophysiological Research.
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- Wadzinski, Thomas L., et al.
(författare)
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Endocrine disruption in human placenta : expression of the dioxin-inducible enzyme, CYP1A1, is correlated with that of thyroid hormone-regulated genes
- 2014
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : Lippincott Williams & Wilkins. - 0021-972X .- 1945-7197. ; 99:12, s. E2735-E2743
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Thyroid hormone (TH) is essential for normal development; therefore, disruption of TH action by a number of industrial chemicals is critical to identify. Several chemicals including polychlorinated biphenyls are metabolized by the dioxin-inducible enzyme CYP1A1; some of their metabolites can interact with the TH receptor. In animals, this mechanism is reflected by a strong correlation between the expression of CYP1A1 mRNA and TH-regulated mRNAs. If this mechanism occurs in humans, we expect that CYP1A1 expression will be positively correlated with the expression of genes regulated by TH.OBJECTIVE: The objective of the study was to test the hypothesis that CYP1A1 mRNA expression is correlated with TH-regulated mRNAs in human placenta.METHODS: One hundred sixty-four placental samples from pregnancies with no thyroid disease were obtained from the GESTE study (Sherbrooke, Québec, Canada). Maternal and cord blood TH levels were measured at birth. The mRNA levels of CYP1A1 and placental TH receptor targets [placental lactogen (PL) and GH-V] were quantitated by quantitative PCR.RESULTS: CYP1A1 mRNA abundance varied 5-fold across 132 placental samples that had detectable CYP1A1 mRNA. CYP1A1 mRNA was positively correlated with PL (r = 0.64; P < .0001) and GH-V (P < .0001, r = 0.62) mRNA. PL and GH-V mRNA were correlated with each other (r = 0.95; P < .0001), suggesting a common activator. The mRNAs not regulated by TH were not correlated with CYP1A1 expression.CONCLUSIONS: CYP1A1 mRNA expression is strongly associated with the expression of TH-regulated target gene mRNAs in human placenta, consistent with the endocrine-disrupting action of metabolites produced by CYP1A1.
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