Training in a Hot Environment Fails to Elicit Changes in the Blood Oxidative Stress Response.

Environmental temperature can impact exercise-induced blood oxidative stress; however, the effects of heat acclimation on this response have not been fully elucidated. The purpose of the study was to investigate the effects of hot (33°C) and room temperature (20°C) environments on post-exercise blood oxidative stress responses following 15 temperature acclimation sessions. Untrained participants (n = 38, 26 ± 7 years, VO2peak = 38.0 ± 7.2 years) completed 15 temperature acclimation sessions of a cycling bout at an intensity perceived as "hard" in either a hot (33°C) or room temperature (20°C) environment. Pre and post acclimation exercise tolerance trials were conducted, which involved cycling at 50% Wpeak for one hour. Blood sampling occurred before exercise, immediately after, two hours, and four hours after the exercise tolerance trials. Blood samples were analyzed for oxidative stress markers including lipid hydroperoxides, 8-isoprostanes, protein carbonyls, 3-nitrotyrosine, ferric-reducing ability of plasma, and Trolox-equivalent antioxidant capacity. Exercise-dependent increases were observed in lipid hydroperoxides, Trolox-equivalent antioxidant capacity, and ferric-reducing ability of plasma (p < 0.001). Considering exercise-induced elevations in markers of blood oxidative stress, there were no differences observed between environmental temperatures before or after the acclimation training period.

Hybrid and Traditional Cardiac Rehabilitation in a Rural Area: A RETROSPECTIVE STUDY.

PURPOSE: Cardiac rehabilitation is a prescribed exercise intervention that reduces cardiovascular mortality, secondary events, and hospitalizations. Hybrid cardiac rehabilitation (HBCR) is an alternative method that overcomes barriers to participation, such as travel distance and transportation issues. To date, comparisons of HBCR and traditional cardiac rehabilitation (TCR) are limited to randomized controlled trials, which may influence outcomes due to supervision associated with clinical research. Coincidental to the COVID-19 pandemic, we investigated HBCR effectiveness (peak metabolic equivalents [peak METs]), resting heart rate (RHR), resting systolic (SBP) and diastolic blood pressure (DBP), body mass index (BMI), and depression outcomes (Patient Health Questionnaire-9 [PHQ-9]). METHODS: Via retrospective analysis, TCR and HBCR were examined during the COVID-19 pandemic (October 1, 2020, and March 31, 2022). Key dependent variables were quantified at baseline (pre) and discharge (post). Completion was determined by participation in 18 monitored TCR exercise sessions and four monitored HBCR exercise sessions. RESULTS: Peak METs increased at post-TCR and HBCR ( P < .001); however, TCR resulted in greater improvements ( P = .034). The PHQ-9 scores were decreased in all groups ( P < .001), while post-SBP and BMI did not improve (SBP: P = .185, BMI: P = .355). Post-DBP and RHR increased (DBP: P = .003, RHR: P = .032), although associations between intervention and program completion were not observed ( P = .172). CONCLUSIONS: Peak METs and depression metric outcomes (PHQ-9) improved with TCR and HBCR. Improvements in exercise capacity were greater with TCR; however, HBCR did not produce inferior results by comparison, an outcome that may have been essential during the first 18 mo of the COVID-19 pandemic.

Carbohydrate Rinse Fails to Enhance Cycling Performance or Alter Metabolic and Autonomic Recovery in Recreational Cyclists.

The purpose of the study was to examine the effects of carbohydrate (CHO) mouth rinsing on autonomic and metabolic recovery as well as cycling performance. Ten male recreational cyclists (age = 30 ± 6 years, VO2peak = 54.5 ± 8.1 mL·kg-1·min-1) completed a randomized, double-blind, placebo-controlled, crossover designed study. A CHO or a placebo (PLA) rinse was administered every 12.5% of a work to completion trial (75%Wmax). Heart rate variability (lnRMSSD), the respiratory exchange ratio, and plasma epinephrine, norepinephrine, insulin, glucose, free fatty acids (FFA), and lactate were measured pre- and post-exercise. The CHO rinse did not improve time to completion of the test trial (CHO: 4108 ± 307 s, PLA: 4176 ± 374 s, p = 0.545). Further, the CHO rinse did not impact autonomic recovery, as measured by lnRMSSD (p = 0.787) and epinephrine (p = 0.132). Metabolic biomarkers were also unaffected by the CHO rinse, with no differences observed in responses of FFA (p = 0.064), lactate (p = 0.302), glucose (p = 0.113) or insulin (p = 0.408). Therefore, the CHO mouth rinse does not reduce the acute sympathetic response following strenuous exercise and does not result in improvements in cycling time to completion.

Cardiovascular and Blood Oxidative Stress Responses to Exercise and Acute Woodsmoke Exposure in Recreationally Active Individuals.

INTRODUCTION: Those who work and recreate outdoors experience woodsmoke exposure during fire season. Exercise during woodsmoke exposure harms the cardiovascular system, but the acute physiologic and biochemical responses are understudied. The purpose of this pilot laboratory-based study was to examine the effect of exercise during woodsmoke exposure on acute indicators of cardiovascular function, including heart rate variability (HRV), pulse wave velocity (PWV), blood pressure (BP), augmentation index (AIx), and blood oxidative stress. METHODS: Ten participants performed 2 moderate-intensity exercise (70% V˙O2 max) trials (clean air 0 µg·m-3, woodsmoke 250 µg·m-3) in a crossover design. HRV, PWV, BP, AIx, and blood oxidative stress were measured before, after, and 90 min after exercise for each trial. Blood oxidative stress was quantified through lipid damage (LOOH, 8-ISO), protein damage (3-NT, PC), and antioxidant capacity (TEAC). RESULTS: A 45-min woodsmoke exposure combined with moderate-intensity exercise did not result in a statistically significant difference in HRV, PWV, BP, AIx, or oxidative stress (P>0.05). CONCLUSIONS: Despite the known deleterious effects of smoke inhalation, moderate-intensity aerobic exercise while exposed to woodsmoke particulate matter (250 µg·m-3) did not result in a statistically significant difference in HRV, PWV, or blood oxidative stress in this methodologic context. Although findings do not negate the negative impact of woodsmoke inhalation, additional research approaches are needed to better understand the acute effects of smoke exposure on the cardiovascular system.

Alterations in Metabolic and Cardiovascular Risk Factors During Critical Training in Wildland Firefighters.

OBJECTIVE: To identify physiologic stressors related to cardiovascular disease via changes in metabolic, inflammatory, and oxidative stress biomarkers during 2 weeks of preseason training in wildland firefighters (WLFFs). METHODS: Participants were recruited from a local hotshot crew and monitored during preseason training. Fitness was assessed via the Bureau of Land Management fitness challenge. Venipuncture blood was collected on days 1, 4, 8, and 11 and analyzed for changes in a lipid and glucose panel, C-reactive protein, and oxidative stress markers 8-isoprostane (8ISO), 3-nitrotyrosine (3NT), lipid hydroperoxides (LOOH), and protein carbonyls. RESULTS: The high physical demands of training resulted in significant (P < 0.05) reductions in total cholesterol, glucose, and hemoglobin A1c. A main effect for time was observed in 8ISO, 3NT, and LOOH. CONCLUSIONS: Alterations in metabolic and oxidative stress markers suggest an acute, high-intensity physical stress during WLFF preseason training.

Muscle Damage and Overreaching During Wildland Firefighter Critical Training.

OBJECTIVE: To document the effects of wildland firefighter (WLFF) critical training (CT) on physiologic markers of muscle damage and acute overreaching. METHODS: Eighteen male and three female WLFFs were studied during an 11-day CT. Upper-body (US), lower-body (LS) muscle soreness and body weight (BW) were collected daily. Blood was collected on days 1, 4, 8, and 11 to measure creatine kinase (CK), lactate dehydrogenase (LDH), cortisol, and testosterone. Skinfolds were taken on days 1 and 11 to estimate body fat (BF) and lean body weight (LBW). RESULTS: CT resulted in a significant depression in BF and elevation in LBW, while main effects of time were seen in US, LS, CK, LDH, cortisol, and testosterone/cortisol ratio (P < 0.05). CONCLUSION: These data suggest WLFFs undergo significant physiological stressors resulting in muscle soreness, damage, and possible overreaching during CT.

Blood oxidative stress and post-exercise recovery are unaffected byhypobaric and hypoxic environments.

Hypobaria and hypoxia exert independent effects on oxidative stress during exercise, while combined effectson the post-exercise recovery period remain unclear.Accordingly, this study examined the recovery period during lab-simulated hypoxic and hypobaric conditions following exercise-induced oxidative stress. Participants (n=13) performed 60-minutes of cycling (70% watts max) in a normobaric normoxic environment followed by a four-hour recovery under three conditions; 1000m normobaric normoxia (NN, 675mmHg), 4400m normobaric hypoxia (NH, 675mmHg), or 4400m hypobaric hypoxia (HH, 440mmHg). Blood samples collected at Pre, Post, 2-Hours (2-HR), and 4-Hours (4-HR) post-exercise were analyzed fora potential increase in biochemical modifications of proteins(protein carbonyls, PC; 3-nitrotyrosines, 3NT) lipids (lipid hydroperoxides, LOOH; 8-isoprostanes, 8-ISO), and antioxidant capacity (FRAP, TEAC). Gene transcripts (EPAS, HMOX1, SOD2, NFE2L2) were quantified by qRT-PCR from muscle biopsies taken Pre and Post exercise. Hypoxia and hypobaria had no effect throughout recovery. Post-exercise TEAC (p=0.041), FRAP (p=0.013), and 8-ISO (p=0.044) increased, while PC (p=0.002) and 3-NT (p=0.032) were decreased. LOOH was lower in Post (p=0.018) NH trial samples. Exercise-dependent increases occurred in NFE2L2 (p=0.003), HMXO1 (p<0.001), SOD2 (p=0.046), and EPAS (p=0.038). Exercise recovery under conditions of NH and HH did not impact blood oxidative stress or redox-sensitive gene transcripts.

Pre-Anticipatory Anxiety and Autonomic Nervous System Response to Two Unique Fitness Competition Workouts.

To evaluate the feasibility of on-site collection of subjective anxiety, autonomic nervous system activity, and salivary catecholamines surrounding high-intensity functional training (HIFT) competition, ten experienced HIFT competitors completed baseline assessments of anxiety and heart rate variability (HRV). Then, in two consecutive weeks (Workout 1 and 2) within the competition, HRV was recorded and examined in 5-min segments prior to exercise (PRE) and across a 30-min period after competitors completed their choice of the prescribed or scaled each workout. Subjective anxiety ratings and saliva samples were collected at PRE and immediately-(IP), 30-min (30P), and 60-min post-exercise (60P). Saliva samples were analyzed for concentrations of epinephrine and norepinephrine. Generalized linear mixed models with repeated measures revealed significant (p < 0.05) differences between workouts for all measures. Compared to Workout 1, anxiety (~50%), epinephrine (173-340%), norepinephrine (29-234%) were greater in Workout 2 and various HRV-derived indices were more depressed. Additionally, some HRV-derived indices appeared to be modulated (p < 0.05) by competitive level and sex at PRE and throughout the 30-min recovery period. These data suggest that autonomic activity may differ between the competitive and laboratory settings, and that the response may be further modulated by the workout's design, the athlete's sex, and competitive level.