What is the most effective exercise protocol to improve cardiovascular fitness in overweight and obese subjects？

Background: Increased peak oxygen consumption(VO2 peak) can reduce cardiovascular risks associated with obesity. Our aim was to analyze the effect of a weight loss program on cardiovascular fitness in overweight(W) and obese(O) subjects.Methods: One hundred and sixty-seven subjects(77 males and 90 females), aged 18–50 years, performed a modified Bruce protocol before(pre)and after(post) a weight loss program of 24 weeks. This program combined physical training(strength, S; endurance, E; combined strength + endurance, SE; or physical activity recommendation, PA) 3 times per week, with a 25%–30% caloric restriction diet.Results: VO2 peak improved in overweight and obese males(pre and post values in L/min, respectively; W = 3.2 ± 0.6 vs. 3.7 ± 0.5, p < 0.001;O = 3.6 ± 0.6 vs. 3.8 ± 0.6, p = 0.013) as well as in overweight females(2.0 ± 0.3 vs. 2.3 ± 0.4, p < 0.001). VO2 peak in the first ventilatory threshold(VT1) increased for all 4 interventions in males(p < 0.05), except for S in the obese group(1.6 ± 0.2 vs. 1.7 ± 0.3, p = 0.141). In females, it increased in E(0.9 ± 0.2 vs. 1.4 ± 0.3, p < 0.001), SE(0.9 ± 0.2 vs. 1.2 ± 0.4, p = 0.003), and PA(0.9 ± 0.1 vs. 1.2 ± 0.2, p = 0.006) in overweight groups. Time-to-exhaustion improved in all subjects except for females in PA group(15.7 ± 0.3 min vs. 15.9 ± 0.3 min, p = 0.495).Conclusion: Our results suggest that all methods, including the recommendation of physical activity, can improve cardiovascular fitness in overweight subjects and obese males.

Factors that affect heart rate variability following acute resistance exercise:A systematic review and meta-analysis

Background:There is controversial evidence regarding the effect of acute resistance exercise(ARE) on heart rate variability(HRV) parameters,which indicates the activities of the cardiac autonomic nervous system.The aim of this study was to perform a systematic review and meta-analysis of the literature on the effect of ARE on HRV parameters and identify its possible moderating factors.Methods:The PubMed-Medline,Web of Science,SPORTDiscus,and Cochrane Library databases were searched.The Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) declaration was followed,and the methodological quality of the studies was evaluated.The level of significance was set at p≤0.05.Twenty-six studies met the inclusion criteria.Main effect analyses between pre-and post-test interventions demonstrated an increase in normalized units low frequency(p <0.001;standardized mean difference(SMD)=0.78;95% confidence interval(95%CI):0.46-1.11) and low frequency/high frequency ratio(p <0.001;SMD=0.82;95%CI:0.64-0.99) and a decrease in standard deviation of the normal-to-normal(NN)interval(p <0.001;SMD=-0.58;95%CI:-0.85 to-0.30),root mean square of the successive differences(p <0.001;SMD=-1.01;95%CI:-1.29 to-0.74),and normalized units high frequency(p <0.001;SMD:-1.08;95%CI:-1.43 to-0.73) following ARE in healthy individuals range:15 ± 1 to 48 ± 2 years;mean ± SD).Results:There were differences between the subgroups in the number of sets used in an exercise(p=0.05) for root mean square of the successive differences,as well as for exercise intensity(p=0.01) and rest between sets(p=0.05) for normalized units high frequency.Interestingly,there were differences between the subgroups in training volume for root mean square of the successive differences(p=0.01),normalized units high frequency(p=0.003) and normalized units low frequency(p=0.02).Conclusion:Overall,there was a withdrawal of cardiac parasympathetic and activation of cardiac sympathetic modulations following ARE,and these changes were greater with higher training volume ~30 min after ARE in healthy individuals.Furthermore,the number of sets,intensity,and rest between sets affected HRV parameters.However,gender,body mass index,and training status did not influence the changes in HRV parameters as a response to ARE.

Effects of medium-and long-distance running on cardiac damage markers in amateur runners:a systematic review,meta-analysis,and metaregression

Background:To finish an endurance race,athletes perform a vigorous effort that induces the release of cardiac damage markers.There are several factors that can affect the total number of these markers,so the aim of this review was to analyze the effect of endurance running races on cardiac damage markers and to identify the factors that modify the levels of segregation of these cardiac damage markers.Methods:A systematic search of PubMed,Web of Science,and the Cochrane Library databases was performed.This analysis included studies where the acute effects of running races on cardiac damage markers(troponin I and troponin T)were analyzed,assessing the levels of these markers before and after the races.Results:The effects of running races on troponin I(mean difference=0.0381 ng/mL)and troponin T(mean difference=0.0256 ng/mL)levels were significant.The ages(R^(2)=14.4%,p=0.033)and body mass indexes(R^(2)=14.5%,p=0.045)of the athletes had a significant interaction with troponin I.In addition,gender,mean speed,time to finish the race,and type of race can affect the level of cardiac damage markers.Conclusion:Endurance running races induce the release of cardiac-damage markers that remain elevated for at least 24 h after the races.In addition,young male athletes with high body mass indexes who perform races combining long duration and moderate intensity(i.e.,marathons)release the highest levels of cardiac damage markers.Physicians should take into consideration these results in the diagnosis and treatment of patients admitted to the hospital days after finishing endurance running races.