Exercise training and resting blood pressure: a large-scale pairwise and network meta-analysis of randomised controlled trials

Objective: To perform a large-scale pairwise and network meta-analysis on the effects of all relevant exercise training modes on resting blood pressure to establish optimal anti-hypertensive exercise prescription practices. Design: Systematic review and network meta-analysis. Data sources: PubMed (MEDLINE), the Cochrane library and Web of Science were systematically searched. Eligibility criteria: Randomised controlled trials published between 1990 and February 2023. All relevant work reporting systolic blood pressure (sBP) and/or diastolic (dBP) reductions following an exercise intervention ≥2 weeks with an eligible non-intervention control group were included. Results: 270 randomised controlled trials were ultimately included in the final analysis, with a pooled sample size of 15,827 participants. Pairwise analyses demonstrated significant reductions in resting sBP and dBP following aerobic exercise training (-4.49/-2.53mmHg, P<0.001), dynamic resistance training (-4.55/-3.04mmHg, P<0.001), combined training (-6.04/-2.54mmHg, P<0.001), high intensity interval training (-4.08/-2.50mmHg, P<0.001) and isometric exercise training (-8.24/-4.00mmHg, P<0.001). As evidenced in the network meta-analysis, the rank order of effectiveness based on the surface under the cumulative ranking curve (SUCRA) values for sBP were isometric exercise training (SUCRA: 98.3%), combined training (75.7%), dynamic resistance training (46.1%), aerobic exercise training (40.5%) and high intensity interval training (39.4%). Secondary network meta-analyses revealed isometric wall squat and running as the most effective sub-modes for reducing sBP (90.4%) and dBP (91.3%) respectively. Conclusion: Various exercise training modes improve resting blood pressure, particularly isometric exercise. The results of this analysis should inform future exercise guideline recommendations for the prevention and treatment of arterial hypertension

Mercury concentrations in blood, brain and muscle tissues of coastal and pelagic birds from northeastern Canada

Mercury (Hg) is a toxic element which has increased in marine environments for more than a century, due largely to anthropogenic activities, and biomagnifies in food chains to harmful levels in some top predators like waterfowl and seabirds. We analysed total mercury (THg) concentrations in blood, brain and muscle tissue from healthy specimens of 13 coastal and pelagic bird species from eastern and northern Canada to provide a baseline on c

Some like it cold: microbial transformations of mercury in polar regions

The contamination of polar regions with mercury that is transported from lower latitudes as inorganic mercury has resulted in the accumulation of methylmercury (MeHg) in food chains, risking the health of humans and wildlife. While production of MeHg has been documented in polar marine and terrestrial environments, little is known about the responsible transformations and transport pathways and the processes that control them. We posit that as in temperate environments, microbial transformations play a key role in mercury geochemical cycling in polar regions by: (1) methylating mercury by one of four proposed pathways, some not previously described; (2) degrading MeHg by activities of mercury resistant and other bacteria; and (3) carrying out redox transformations that control the supply of the mercuric ion, the substrate of methylation reactions. Recent analyses have identified a high potential for mercury-resistant microbes that express the enzyme mercuric reductase to affect the production of gaseous elemental mercury when and where daylight is limited. The integration of microbially mediated processes in the paradigms that describe mercury geochemical cycling is therefore of high priority especially in light of concerns regarding the effect of global warming and permafrost thawing on input of MeHg to polar regions