Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial.

A supervised intense aerobic exercise program improves the health of individuals with metabolic syndrome (MetS). However, it is unclear whether the timing of training within the 24 h day would influence those health benefits. The present study aimed to determine the influence of morning vs. afternoon exercise on body composition, cardiometabolic health and components of MetS. One hundred thirty-nine individuals with MetS were block randomized into morning (AMEX; n = 42) or afternoon (PMEX; n = 59) exercise training groups, or a non-training control group (Control; n = 38). Exercise training was comprised of 48 supervised high-intensity interval sessions distributed over 16 weeks. Body composition, cardiorespiratory fitness (assessed by V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ), maximal fat oxidation (FOmax ), blood pressure and blood metabolites were assessed before and after the intervention. Compared with the non-training Control, both exercise groups improved similarly body composition (-0.7% fat loss; P = 0.002), waist circumference (-2.1 cm; P < 0.001), diastolic blood pressure (-3.8 mmHg; P = 0.004) and V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ (3.5 mL kg-1   min-1 ; P < 0.001) with no differences between training groups. AMEX, in comparison with PMEX, reduced systolic blood pressure (-4% vs. -1%; P = 0.019), plasma fasting insulin concentration (-12% vs. -5%; P = 0.001) and insulin resistance (-14% vs. -4%; P = 0.006). Furthermore, MetS Z score was further reduced in the AMEX compared to PMEX (-52% vs. -19%; P = 0.021) after training. In summary, high-intensity aerobic exercise training in the morning in comparison to training in the afternoon is somewhat more efficient at reducing cardiometabolic risk factors (i.e. systolic blood pressure and insulin sensitivity). KEY POINTS: The effect of exercise time of day on health promotion is an area that has gained interest in recent years; however, large-scale, randomized-control studies are scarce. People with metabolic syndrome (MetS) are at risk of developing cardiometabolic diseases and reductions in this risk with exercise training can be precisely gauged using a compound score sensitive to subtle evolution in each MetS component (i.e. Z score). Supervised aerobic exercise for 16 weeks (morning and afternoon), without dietary restriction, improved cardiorespiratory and metabolic fitness, body composition and mean arterial pressure compared to a non-exercise control group. However, training in the morning, without changes in exercise dose or intensity, reduced systolic blood pressure and insulin resistance further compared to when training in the afternoon. Thus, high-intensity aerobic exercise training in the morning is somewhat more efficient in improving the health of individuals with metabolic syndrome.

Chronic Statin Treatment Does Not Impair Exercise Lipolysis or Fat Oxidation in Exercise-Trained Individuals With Obesity and Dyslipidemia.

OBJECTIVE: To determine whether statin medication in individuals with obesity, dyslipidemia, and metabolic syndrome affects their capacity to mobilize and oxidize fat during exercise. METHODS: Twelve individuals with metabolic syndrome pedaled during 75 min at 54 ± 13% V˙O2max (5.7 ± 0.5 metabolic equivalents) while taking statins (STATs) or after 96-hr statin withdrawal (PLAC) in a randomized double-blind fashion. RESULTS: At rest, PLAC increased low-density lipoprotein cholesterol (i.e., STAT 2.55 ± 0.96 vs. PLAC 3.16 ± 0.76 mmol/L; p = .004) and total cholesterol blood levels (i.e., STAT 4.39 ± 1.16 vs. PLAC 4.98 ± 0.97 mmol/L; p = .008). At rest, fat oxidation (0.99 ± 0.34 vs. 0.76 ± 0.37 µmol·kg-1·min-1 for STAT vs. PLAC; p = .068) and the rates of plasma appearance of glucose and glycerol (i.e., Ra glucose-glycerol) were not affected by PLAC. After 70 min of exercise, fat oxidation was similar between trials (2.94 ± 1.56 vs. 3.06 ± 1.94 µmol·kg-1·min-1, STA vs. PLAC; p = .875). PLAC did not alter the rates of disappearance of glucose in plasma during exercise (i.e., 23.9 ± 6.9 vs. 24.5 ± 8.2 µmol·kg-1·min-1 for STAT vs. PLAC; p = .611) or the rate of plasma appearance of glycerol (i.e., 8.5 ± 1.9 vs. 7.9 ± 1.8 µmol·kg-1·min-1 for STAT vs. PLAC; p = .262). CONCLUSIONS: In patients with obesity, dyslipidemia, and metabolic syndrome, statins do not compromise their ability to mobilize and oxidize fat at rest or during prolonged, moderately intense exercise (i.e., equivalent to brisk walking). In these patients, the combination of statins and exercise could help to better manage their dyslipidemia.

Effects of statins and exercise on postprandial lipoproteins in metabolic syndrome vs metabolically healthy individuals.

AIMS: To determine if the combination of exercise and statin could normalize postprandial triglyceridaemia (PPTG) in hypercholesteraemic individuals. METHODS: Eight hypercholesteraemic (blood cholesterol 182 ± 38 mg dL-1 ; low-density lipoprotein-cholesterol [LDL-c] 102 ± 32 mg dL-1 ) overweight (body mass index 30 ± 4 kg m-2 ) individuals with metabolic syndrome (MetS) were compared to a group of 8 metabolically healthy (MetH) controls (blood cholesterol 149 ± 23 mg dL-1 ; LDL-c 77 ± 23 mg dL-1 , and body mass index 23 ± 2 kg m-2 ). Each group underwent 2 PPTG tests, either 14 hours after a bout of intense exercise or without previous exercise. Additionally, MetS individuals were tested 96 hours after withdrawal of their habitual statin medication to study medication effects. RESULTS: A bout of exercise before the test meal did not reduce PPTG in MetS (P = .347), but reduced PPTG by 46% in MetH (413 ± 267 to 224 ± 142 mg dL-1 for 5 h incremental area under the curve; P = .02). In both trials (i.e., either after a bout of intense exercise or without previous exercise), statin withdrawal in MetS greatly increased PPTG (average 65%; P < .01), mean LDL-c (average 25%; P < .01), total cholesterol (average 16%; P < .01) and apolipoprotein (Apo) B48 (24%; P < .01), without interference from exercise. However, Apo B100 was not affected by statin withdrawal. CONCLUSION: Hypercholesteraemic MetS individuals (compared to MetH controls) fail to show an effect of exercise on reducing PPTG. However, chronic statin medication blunts the elevations in triglyceride after a fat meal (i.e., incremental area under the curve of PPTG) reducing their cardiovascular risk associated with their atherogenic dyslipidaemia. Statin decreases PPTG by reducing the secretion or accelerating the catabolism of intestinal Apo B48.

Effects of antihypertensive medication and high-intensity interval training in hypertensive metabolic syndrome individuals.

Pharmacological and non-pharmacological therapies are simultaneously prescribed when treating hypertensive individuals with elevated cardiovascular risk (ie, metabolic syndrome individuals). However, it is unknown if the interactions between antihypertensive medication (AHM) and lifestyle interventions (ie, exercise training) may result in a better ambulatory blood pressure (ABP) control. To test this hypothesis, 36 hypertensive individuals with metabolic syndrome (MetS) under long-term prescription with AHM targeting the renin-angiotensin-aldosterone system (RAAS) were recruited. Before and after 4 months of high-intensity interval training (HIIT), participants completed two trials in a double-blind, randomized order: (a) placebo trial consisting of AHM withdrawal for 3 days and (b) AHM trial where individuals held their habitual dose of AHM. In each trial, 24-h mean arterial pressure (MAP) was monitored and considered the primary study outcome. Secondary outcomes included plasma renin activity (PRA) and aldosterone concentration to confirm withdrawal effects on RAAS, along with the analysis of urine albumin-to-creatinine ratio (UACR) to assess kidney function. The results showed main effects from AHM and HIIT reducing 24-h MAP (-5.7 mmHg, p < 0.001 and -2.3 mmHg, p = 0.007, respectively). However, there was not interaction between AHM and HIIT on 24-h MAP (p = 0.240). There was a main effect of AHM increasing PRA (p < 0.001) but no effect on plasma aldosterone concentration (p = 0.368). HIIT did not significantly improve RAAS hormones or the UACR. In conclusion, AHM and HIIT have independent and additive effects in lowering ABP. These findings support the combination of habitual AHM with exercise training with the goal to reduce ABP in hypertensive MetS individuals.

Importance of a verification test to accurately assess V̇O2 max in unfit individuals with obesity.

BACKGROUND: To determine the trustworthiness of graded exercise test to exhaustion (GXT) to assess maximal oxygen uptake ( V ˙ O 2 max ) in metabolic syndrome individuals with obesity and poor cardiorespiratory fitness. METHODS: V ˙ O 2 max was assessed in 100 metabolic syndrome adults (57 ± 8 years; 34% women), with obesity (BMI 32 ± 5 kg·m-2 ) using GXT followed by supramaximal constant-load verification test (VerT) at 110% of maximal GXT work rate. V ˙ O 2 data from GXT and VerT were compared using paired t test and plotted for Bland-Altman analysis. GXT sensitivity and specificity to detect V ˙ O 2 max were also calculated. RESULTS: Seventy individuals did not achieve V ˙ O 2 plateau during GXT. GXT underestimated V ˙ O 2 max in 40 subjects. In these subjects, the magnitude of V ˙ O 2 max underestimation with GXT was 9% (167 mLO2 ·min-1 ; P < .001). In the whole sample (n = 100), bias error differences between GXT and VerT was 63 mLO2 ·min-1 (3% underestimation). This error was constant regardless of differences in fitness levels among individuals (R = -0.07; homoscedasticity). GXT results were unreliable in 62% of the sample with 16% of false-positive and 46% of false-negative results. Sensitivity and specificity of GTX to assess V ˙ O 2 max were low (ie, 23% and 60%, respectively). CONCLUSION: Our data indicate that the magnitude (3%-9%) and prevalence (40% of subjects) of V ˙ O 2 max underestimation with the use of a GXT alone is high in a large sample of unfit metabolic syndrome individuals with obesity. Our data advocate for the need of using VerT after GXT to avoid significant cardiorespiratory fitness underestimation in metabolic syndrome individuals with obesity and low fitness level.

Synchronized Pedaling with Martial Arts Improves Quality of Life of Women with Breast Cancer.

Physical exercise improves the physical condition of women who have been undergone surgery for breast cancer. This study evaluated the effect of a new martial arts program that combined aerobic endurance and muscle strength exercises on improving upper limb function and aerobic performance of women who have undergone breast cancer surgery. Fifty-three women who had previously undergone breast cancer surgery with axillary lymph node dissection, radiotherapy and/or chemotherapy participated in the twelve-week program. Participants were randomly assigned to two groups; a study group (28 participants) in which participants carried out a synchronized pedaling with martial arts routine of 2 sessions per week, and a control group (22 participants) who received usual care. Study group participants demonstrated a significant increase in right hand and quadriceps strength, maximum oxygen consumption, max power-to-weight ratio, muscle mass percentage and a decrease in fat mass percentage (p≤0.05). A controlled training system like synchronized pedaling with martial arts, which combines aerobic and strength exercises, appears suitable for improving the muscle strength and aerobic capacity of these breast cancer participants.

Circadian rhythm effect on physical tennis performance in trained male players.

To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h-1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.

Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans.

PURPOSE: It is usually stated that glycogen is stored in human muscle bound to water in a proportion of 1:3 g. We investigated this proportion in biopsy samples during recovery from prolonged exercise. METHODS: On two occasions, nine aerobically trained subjects ([Formula: see text] = 54.4 ± 1.05 mL kg(-1) min(-1); mean ± SD) dehydrated 4.6 ± 0.2 % by cycling 150 min at 65 % [Formula: see text] in a hot-dry environment (33 ± 4 °C). One hour after exercise subjects ingested 250 g of carbohydrates in 400 mL of water (REHLOW) or the same syrup plus water to match fluid losses (i.e., 3170 ± 190 mL; REHFULL). Muscle biopsies were obtained before, 1 and 4 h after exercise. RESULTS: In both trials muscle water decreased from pre-exercise similarly by 13 ± 6 % and muscle glycogen by 44 ± 10 % (P < 0.05). After recovery, glycogen levels were similar in both trials (79 ± 15 and 87 ± 18 g kg(-1) dry muscle; P = 0.20) while muscle water content was higher in REHFULL than in REHLOW (3814 ± 222 vs. 3459 ± 324 g kg(-1) dm, respectively; P < 0.05; ES = 1.06). Despite the insufficient water provided during REHLOW, per each gram of glycogen, 3 g of water was stored in muscle (recovery ratio 1:3) while during REHFULL this ratio was higher (1:17). CONCLUSIONS: Our findings agree with the long held notion that each gram of glycogen is stored in human muscle with at least 3 g of water. Higher ratios are possible (e.g., during REHFULL) likely due to water storage not bound to glycogen.

Ingestion of a moderately high caffeine dose before exercise increases postexercise energy expenditure.

Caffeine is an ergogenic aid widely used before and during prolonged exercise. Due to its prolonged biological half-life caffeine effects could remain after exercise. We aimed to investigate the metabolic, respiratory, and cardiovascular postexercise responses to preexercise graded caffeine ingestion. Twelve aerobically trained subjects (mean VO2max = 54 ± 7 ml · min⁻¹ · kg⁻¹) cycled for 60-min at 75% VO2max after ingesting placebo (0 mg of caffeine per kg of body weight) or 0.5, 1.5, 3.0 and 4.5 mg · kg⁻¹ on five occasions. During the 3 hr postexercise, heart rate, blood pressure, glucose, lactate, and fatty acids were analyzed. None of these variables were statistically affected by preexercise caffeine ingestion between 0.5 and 4.5 mg · kg⁻¹. However, ingestion of 4.5 mg · kg⁻¹ of caffeine raised postexercise energy expenditure 15% above placebo (233 ± 58 vs. 202 ± 49 kcal/3 hr; p < .05). Ventilation and tidal volume were elevated after the 4.5 mg · kg⁻¹ caffeine dose above placebo (9.2 ± 2.5 L · min⁻¹ and 0.67 ± 0.29 L · breath⁻¹ vs. 7.8 ± 1.5 L · min⁻¹ and 0.56 ± 0.20 L · breath⁻¹, respectively; p < .05). Ventilation correlated with tidal volume (r = .45; p < .05) and energy expenditure (r = .72; p < .05). In summary, preexercise ingestion of ergogenic caffeine doses do not alter postexercise cardiovascular responses. However, ingestion of 4.5 mg · kg⁻¹ of caffeine raises 3-hr postexercise energy expenditure (i.e., 31 kcal) likely through increased energy cost of ventilation.

A Varian DynaLog file-based procedure for patient dose-volume histogram-based IMRT QA.

In the present study, we describe a method based on the analysis of the dynamic MLC log files (DynaLog) generated by the controller of a Varian linear accelerator in order to perform patient-specific IMRT QA. The DynaLog files of a Varian Millennium MLC, recorded during an IMRT treatment, can be processed using a MATLAB-based code in order to generate the actual fluence for each beam and so recalculate the actual patient dose distribution using the Eclipse treatment planning system. The accuracy of the DynaLog-based dose reconstruction procedure was assessed by introducing ten intended errors to perturb the fluence of the beams of a reference plan such that ten subsequent erroneous plans were generated. In-phantom measurements with an ionization chamber (ion chamber) and planar dose measurements using an EPID system were performed to investigate the correlation between the measured dose changes and the expected ones detected by the reconstructed plans for the ten intended erroneous cases. Moreover, the method was applied to 20 cases of clinical plans for different locations (prostate, lung, breast, and head and neck). A dose-volume histogram (DVH) metric was used to evaluate the impact of the delivery errors in terms of dose to the patient. The ionometric measurements revealed a significant positive correlation (R² = 0.9993) between the variations of the dose induced in the erroneous plans with respect to the reference plan and the corresponding changes indicated by the DynaLog-based reconstructed plans. The EPID measurements showed that the accuracy of the DynaLog-based method to reconstruct the beam fluence was comparable with the dosimetric resolution of the portal dosimetry used in this work (3%/3 mm). The DynaLog-based reconstruction method described in this study is a suitable tool to perform a patient-specific IMRT QA. This method allows us to perform patient-specific IMRT QA by evaluating the result based on the DVH metric of the planning CT image (patient DVH-based IMRT QA).

Effect of Yearly Exercise on Medication Expense and Benefit-Cost Ratio in Individuals with Metabolic Syndrome: A Randomized Clinical Trial.

INTRODUCTION: Lifestyle modification through incorporation of exercise training could improve metabolic syndrome (MetS) clinical components (hypertension, dyslipidemia, hyperglycemia, and visceral abdominal obesity). We aimed to assess if long-term exercise training could restrain the increased pharmacological cost of the clinical management of the MetS. METHODS: Medicine cost during a 5-yr-long randomized controlled exercise intervention trial was analyzed. After a per-protocol analysis, a group of 64 individuals 53 ± 2 yr old, with overweight (body mass index, 33.4 ± 0.9 kg·m -2 ) and MetS (3.6 ± 0.2 factors) were randomized to a training (4 months·yr -1 for 5 yr; EXERCISE, n = 25) or to a control group (CONTROL, n = 26). Subjects were studied on three occasions during the 5-yr follow-up. Participants continued their routine medication managed by their general practitioner. The main outcome is the 5-yr evolution of medication cost to treat MetS (hyperglycemia, hypertension, and hyperlipidemia). A secondary outcome is the benefit-cost ratio of the exercise intervention. RESULTS: In CONTROL, medicine cost increased 160% from baseline ( P < 0.001), whereas in EXERCISE, it remained unchanged (33%; P = 0.25). After the 5-yr follow-up, medicine use was 60% and medicine cost 74% higher in CONTROL than EXERCISE ( P < 0.05 in both cases). However, MetS z score was similarly reduced over time in both groups ( P = 0.244 for group-time interaction). The number of prescribed medications increased after 5 yr in CONTROL (89%; P < 0.001), whereas it remained stable with yearly training (17%; P = 0.72 in EXERCISE). Ten-year atherosclerotic cardiovascular disease risk estimation increased only in CONTROL (15%; P = 0.05 for group-time interaction). The benefit in medicine savings (€153 per year and patient) triplicated the estimated cost (€50.8 per year and patient) of the exercise intervention. CONCLUSIONS: A 5-yr-long supervised exercise training program in middle-age individuals with MetS prevents the need for increasing medicine use. The savings in pharmacological therapy outweighs the estimated costs of implementing the exercise program.

Effects of Statins on Fat Oxidation Improvements After Aerobic Exercise Training.

CONTEXT: Statins blunt cardiorespiratory fitness improvements after exercise training and may affect fat oxidation adaptations to training. OBJECTIVE: To determine if long-term statin use in dyslipidemic individuals restricts the improvements in fat oxidation typically observed after an intense exercise-training program. METHODS: A total of 106 metabolic syndrome individuals either chronically medicated with statins (ie, statin group; n = 46) or statin naive (ie, control group; n = 60) completed a 16-week supervised high-intensity interval training program. Maximal rates of oxygen consumption (V˙O2MAX), fat oxidation (FOMAX), and the shape of the workload-fat oxidation curve were assessed before and 48 hours after training in an overnight fasted state. RESULTS: Starting from a similar value at baseline, both groups increased V˙O2MAX after training, but the increase was larger in the control than in the statin group (19.4% vs 12.6%; P = .013). Before training, FOMAX in the statin group was lower (0.19 ± 0.08 vs 0.23 ± 0.07 g·min-1; P = .023) and took place at a lower workload (33 ± 21 vs 37 ± 19 W; P = .015) than in the control group. After training, FOMAX improved similarly in both groups (0.06 ± 0.08; 95% CI, 0.03-0.08 g·min-1 and 0.05 ± 0.09; 95% CI, 0.03-0.07 g·min-1, for statin and control groups, respectively; (P < .001). Still, after training, FOMAX occurred at a 28% lower workload in the statin group (38 ± 26 vs 53 ± 32 W; P = .048). The V˙O2-workload slope decreased after training in both groups (both P < .001) along with reductions in the respiratory exchange ratio-workload slope. Fat oxidation increased at all workloads after training regardless of the use of statins. CONCLUSION: Long-term statin treatment is associated with blunted exercise fat oxidation before exercise training. However, statin use does not attenuate the improvements in exercise fat oxidation (FOMAX) derived from intense aerobic exercise training. This finding should encourage statin users to exercise-train to benefit from increased fat oxidation once their fitness level improves.

Effects of statin therapy on glycemic control and insulin resistance: A systematic review and meta-analysis.

AIMS: To update the evidence about the diabetogenic effect of statins. METHODS: We searched for randomized-controlled trials reporting the effects of statin therapy on glycosylated hemoglobin (HbA1c) and/or homeostatic model insulin resistance (i.e., HOMA-IR) as indexes of diabetes. Studies were classified between the ones testing normal vs individuals with already altered glycemic control (HbA1c ≥ 6.5%; and HOMA-IR ≥ 2.15). Furthermore, studies were separated by statin type and dosage prescribed. Data are presented as mean difference (MD) and 95% confidence intervals. RESULTS: A total of 67 studies were included in the analysis (>25,000 individuals). In individuals with altered glycemic control, statins increased HbA1c levels (MD 0.21%, 95% CI 0.16-to-0.25) and HOMA-IR index (MD 0.31, 95% CI 0.24-to-0.38). In individuals with normal glycemic control, statin increased HbA1c (MD 1.33%, 95% CI 1.31-to-1.35) and HOMA-IR (MD 0.49, 95% CI 0.41-to-0.58) in comparison to the placebo groups. The dose or type of statins did not modulate the diabetogenic effect. CONCLUSIONS: Statins, slightly but significantly raise indexes of diabetes in individuals with adequate or altered glycemic control. The diabetogenic effect does not seem to be influenced by the type or dosage of statin prescribed.

Acute Statin Withdrawal Does not Interfere With the Improvements of a Session of Exercise in Postprandial Metabolism.

BACKGROUND: The risk for atherogenic plaque formation is high after ingestion of meals in individuals with high blood lipid levels (ie, dyslipidemia). Statins and exercise reduce the rise of blood triglyceride concentrations after a meal, but the effect of their combination is unclear. METHODS: In a randomized crossover design, 11 individuals with dyslipidemia and metabolic syndrome treated with statins underwent a mixed-meal (970 ± 111 kcal, 24% fat, and 34% carbohydrate) tolerance test. Plasma lipid concentrations, fat oxidation, glucose, and glycerol kinetics were monitored immediately prior and during the meal test. Trials were conducted with participants under their habitual statin treatment and 96 hours after blinded statin withdrawal. Trials were duplicated after a prolonged bout of low-intensity exercise (75 minutes at 53 ± 4% maximal oxygen consumption) to study the interactions between exercise and statins. RESULTS: Statins reduced postprandial plasma triglycerides from 3.03 ± 0.85 to 2.52 ± 0.86 mmol·L-1 (17%; P = .015) and plasma glycerol concentrations (ie, surrogate of whole-body lipolysis) without reducing plasma free fatty acid concentration or fat oxidation. Prior exercise increased postprandial plasma glycerol levels (P = .029) and fat oxidation rates (P = .024). Exercise decreased postprandial plasma insulin levels (241 ± 116 vs 301 ± 172 ρmol·L-1; P = .026) but not enough to increase insulin sensitivity (P = .614). Neither statins nor exercise affected plasma glucose appearance rates from exogenous or endogenous sources. CONCLUSIONS: In dyslipidemic individuals, statins reduce blood triglyceride concentrations after a meal, but without limiting fat oxidation. Statins do not interfere with exercise lowering the postprandial insulin that likely promotes fat oxidation. Last, statins do not restrict the rates of plasma incorporation or oxidation of the ingested glucose.

Aerobic exercise training improves nocturnal blood pressure dipping in medicated hypertensive individuals.

OBJECTIVE: The absence of nocturnal blood pressure (BP) reduction at night in hypertensive individuals is associated with an increased cardiovascular risk. The main purpose of the present study was to investigate the effects of an aerobic training intervention on nocturnal BP dipping in medicated hypertensive individuals. METHODS: At baseline, hypertensive individuals under pharmacological treatment underwent 24-h ambulatory BP monitoring and a morning urine sample to analyze albumin creatinine ratio (UACR). Then, participants were divided into nocturnal dippers ( N = 15; 59 ± 6 years) and nondippers ( N = 20; 58 ± 5 years) according to a day-to-night BP reduction of >10% or <10%, respectively. Next, participants underwent a 3-weekly, 4-month aerobic interval training intervention. RESULTS: Follow-up measurements revealed a reduction in daytime diastolic BP in dippers and nondippers ( Ptime < 0.001), whereas nighttime systolic BP was reduced only in nondippers ( P = 0.004). Regarding dipping pattern, nocturnal systolic BP dipping increased after training in nondippers (5 ± 3 to 9 ± 7%; P = 0.018), whereas in dippers, there was a decrease in nocturnal dipping after training (14 ± 4 to 10 ± 7%, P = 0.016). Nocturnal diastolic BP dipping did not change in nondippers (8 ± 5 to 10 ± 7%; P = 0.273) but decreased in dippers (17 ± 6 to 12 ± 8%; P = 0.004). In addition, UACR was significantly reduced in both groups after training ( Ptime = 0.020). CONCLUSION: Aerobic exercise training is associated with nocturnal BP dipping as nighttime BP was lower than before the program in medicated hypertensive individuals with an initial nondipping phenotype. The lack of improvement in individuals with a dipping phenotype warrants further investigation to discern whether dipping phenotypes influence BP responses to exercise training.

Effectiveness of statins vs. exercise on reducing postprandial hypertriglyceridemia in dyslipidemic population: A systematic review and network meta-analysis.

BACKGROUND: Individuals at risk of suffering cardiovascular disease (CVD) present with larger increases in blood triglyceride (TG) concentration after a high-fat meal than do healthy individuals. These postprandial hypertriglyceride levels are an independent risk factor for CVD. Prescription of statins and a bout of prolonged exercise are both effective in lowering postprandial hypertriglyceride levels. We aimed to evaluate the comparative effectiveness of statins vs. a bout of aerobic exercise in reducing fasting and postprandial TG (PPTG) concentrations in individuals at high risk of developing CVD. METHODS: Thirty-seven studies from a systematic literature search of the PubMed, EMBASE, and Cochrane databases were included in this review. The selected studies conducted trials involving statin therapy (n = 20) or a bout of aerobic exercise (n = 19) and measured their impact on PPTG levels as the outcome. Two studies analyzed both treatments and were included in duplicate. The meta-analysis was constructed using a random-effects model to calculate the mean difference (MD). The Student t test was used to compare the data sets for statins vs. exercise. RESULTS: Overall, statin and exercise interventions showed similar reductions in PPTG levels, with an MD of -0.65 mmol/L for statins (95% confidence interval (95%CI): -0.54 to -0.77; p < 0.001) and -0.46 mmol/L for exercise (95%CI: -0.21 to -0.71; p < 0.01). However, statins lowered fasting TG levels more than exercise (MD = -1.54 mmol/L, 95%CI: -2.25 to -0.83; p = 0.009). CONCLUSION: Although aerobic exercise is effective in lowering blood TG levels, statins seem to be more efficient, especially in the fasted state. A combination of exercise and statins might reveal a valuable approach to the treatment and prevention of CVD. More studies are required to determine the underlying mechanisms and the possible additive effects of these interventions.

In a hot-dry environment racewalking increases the risk of hyperthermia in comparison to when running at a similar velocity.

The purpose of this study was to determine if in a hot-dry environment, racewalking increases intestinal temperature (T(int)) above the levels observed when running either at the same velocity or at a similar rate of heat production. Nine trained racewalkers exercised for 60 min in a hot-dry environment (30.0 ± 1.4°C; 33 ± 8% relative humidity; 2.4 m s(-1) air speed) on three separate occasions: (1) racewalking at 10.9 ± 1.0 km h(-1) (Walk), (2) running at the same velocity (RunVel) and (3) running at 13 ± 1.8 km h(-1) to obtain a similar [Formula: see text] than during Walk (Run[Formula: see text]). As designed, energy expenditure rate was similar during Walk and Run[Formula: see text], but lower during RunVel (842 ± 78 and 827 ± 75 vs. 713 ± 55 W; p < 0.01). Final T(int) was lower during RunVel than during both Walk and Run[Formula: see text] (38.4 ± 0.3 vs. 39.2 ± 0.4 and 39.0 ± 0.4°C; p < 0.01). Heart rate and sweat rate were also lower during RunVel than during Walk and Run[Formula: see text] (i.e. heart rate 159 ± 13 vs. 179 ± 11 and 181 ± 11 beats min(-1) and sweat rate 0.8 ± 0.3 vs. 1.1 ± 0.3 and 1.1 ± 0.3 L h(-1); p < 0.01). However, we could not detect differences in skin temperature among trials. In conclusion, our data indicate that in a hot-dry environment racewalking increases the risk of hyperthermia in comparison with when running at a similar velocity. However, exercise mode (walking vs. running) had no measurable impact on T(INT) or heat dissipation when matched for energy expenditure.

Sweat sodium concentration during exercise in the heat in aerobically trained and untrained humans.

The purpose of this study was to determine whether sweat sodium concentration ([Na(+)](sweat)) during exercise in the heat differs between aerobically trained and untrained individuals. On three occasions, ten endurance-trained (Tr) and ten untrained (UTr) subjects (VO2peak = 4.0 ± 0.8 vs. 3.4 ± 0.7 L min(-1), respectively; P < 0.05) cycled in a hot-ventilated environment (36 ± 1°C; 25 ± 2% humidity, airflow 2.5 m s(-1)) at three workloads (i.e., 40, 60, and 80% VO2peak). Whole-body (SR(WB)) and back sweat rates (SR(BACK)) were measured. At the conclusion of the study, Na(+) in sweat and blood samples was analyzed to calculate Na(+) secretion and reabsorption rates. SR(WB) and SR(BACK) were highly correlated in Tr and UTr (r = 0.74 and 0.79, respectively; P < 0.0001). In both groups, SR(BACK) increased with the increases in exercise intensity (P < 0.05). Likewise, [Na(+)](sweat) increased with the exercise intensity in both groups (P < 0.05) and it tended to be higher in Tr than in UTr at 60 and 80% VO2peak (~22 mmol L(-1) higher; P = 0.06). However, when normalized for SR(BACK), [Na(+)](sweat) was not different between groups. In both groups, Na(+) secretion and reabsorption rates increased with the increases in SR(BACK) (P < 0.05). However, Na(+) reabsorption rate was lower in the Tr than in the UTr (mean slope = 48 vs. 82 ηmol cm(-2) min(-1); P = 0.03). In conclusion, using a cross-sectional study design, our data suggest that aerobic fitness level does not reduce sweat Na(+) secretion or enhance Na(+) reabsorption during prolonged exercise in the heat that induced high sweat rates.

Relevance of individual characteristics for thermoregulation during exercise in a hot-dry environment.

The aim of this study was to investigate the relevance of individual characteristics for thermoregulation during prolonged cycling in the heat. For this purpose, 28 subjects cycled for 60 min at 60% VO(2peak) in a hot-dry environment (36 ± 1°C; 25 ± 2% relative humidity, airflow 2.5 m/s). Subjects had a wide range of body mass (99-43 kg), body surface area (2.2-1.4 m(2)), body fatness (28-5%) and aerobic fitness level (VO(2peak) = 5.0-2.1 L/min). At rest and during exercise, rectal and mean skin temperatures were measured to calculate the increase in body temperature (ΔT (body)) during the trial. Net metabolic heat production (M (NET)) and potential heat loss (by means of evaporation, radiation and convection) were calculated. Although subjects exercised at the same relative intensity, ΔT (body) presented high between-subjects variability (range from 0.44 to 1.65°C). ΔT (body) correlated negatively with body mass (r = -0.49; P < 0.01), body surface area (r = -0.47; P < 0.01) and T(body) at rest (r = -0.37; P < 0.05), but it did not significantly correlate with body fatness (r = 0.12; P > 0.05). ΔT (body) positively correlated with the body surface area/mass ratio (r = 0.46; P < 0.01) and the difference between M (NET) and potential heat loss (r = 0.56; P < 0.01). In conclusion, a large body size (mass and body surface area) is beneficial to reduce ΔT (body) during cycling exercise in the heat. However, subjects with higher absolute heat production (more aerobically fit) accumulate more heat because heat production may exceed potential heat loss (uncompensability).

Exercise Reduces Medication for Metabolic Syndrome Management: A 5-Year Follow-up Study.

PURPOSE: This study aimed to determine the effects of a 5-yr exercise intervention on metabolic syndrome (MetS) and health-related variables and medication use for MetS management. METHODS: Participants were randomly assigned to an exercise intervention (n = 25, 54 ± 2 yr, 20% women) or control group (n = 26, 54 ± 2 yr, 38% women). The intervention lasted 4 months per year and consisted of high-intensity interval training on a cycloergometer thrice a week. Outcomes were MetS z-score and medication use score, MetS-related variables (including blood pressure, blood glucose homeostasis, and lipid profile), and cardiorespiratory fitness (CRF, as determined by maximal oxygen uptake). RESULTS: MetS z-score was similarly reduced over time in both groups (P = 0.244 for group-time interaction). A quasi-significant and significant group-time interaction was found for MetS number of factors (P = 0.004) and CRF (P < 0.001), respectively. Thus, MetS factors tended to decrease over time only in the exercise group with no change in the control group, whereas CRF increased from baseline to 5-yr assessment in the exercise group (by 1.1 MET, P < 0.001) but decreased in the control group (-0.5 MET, P = 0.025). Medicine use score increased twofold from baseline to 5-yr follow-up in the control group (P < 0.001) but did not significantly change (10%, P = 0.52) in the exercise group (P < 0.001 for group-time interaction). The proportion of medicated patients who had to increase antihypertensive (P < 0.001), glucose-lowering (P = 0.036), or total medication (P < 0.0001) over the 5-yr period was lower in the exercise than that in the control group. CONCLUSIONS: Exercise training can attenuate the increase in medication that would be otherwise required to manage MetS over a 5-yr period.