Impact of Astaxanthin Supplementation on Postprandial Oxidative Stress

Astaxanthin is a naturally occurring carotenoid found in salmon and microalgae that has antioxidative properties. Previous research shows dietary supplementation may result in increased endogenous antioxidant status and reduced markers of oxidative stress (OS). Research suggests OS causes increased risk for cardiometabolic and other chronic diseases, making it important to find interventions that can decrease occurrence of OS. While astaxanthin has been shown to be antioxidative, most studies observing the impact of astaxanthin has on OS has involved rodent models, therefore human trials are needed. PURPOSE: The purpose of this study was to assess whether four weeks of astaxanthin supplementation (6mg/day) can decrease blood markers of oxidative stress following the consumption of a high fat meal in healthy, young men. METHODS: Participants (n=13) were healthy, young men (mean ±SD; Age: 23.7 ±2.7 yrs; Weight: 79.8 ±12.6 kg; Height: 171.7 ±5.9 cm) that completed a randomized, double blinded crossover counterbalanced study. All participants completed 4 weeks of 6 mg of astaxanthin supplementation in addition to 4 weeks of placebo supplementation with a one-week washout period between treatments. After each supplementation period, participants consumed a high fat milkshake (milkshake; 1g fat/kg body weight, 1g carbohydrate/kg body weight, 0.25g protein/kg body weight) to induce postprandial OS. Blood samples were taken immediately before, as well as two, and four hours post milkshake consumption. The following were analyzed from each blood sample: triglycerides (TAG), glutathione (GSH), hydrogen peroxide (H2O2), malondialdehyde (MDA), and advanced oxidation protein products (AOPP). RESULTS: Participant compliance on average was 98%. Regarding AOPP, there was no treatment x timepoint interaction or a significant main effect for treatment, while there was a main effect for time (F = 17.14, p \u3c 0.01) with significantly higher levels of AOPP at two and four hours postprandial compared to pre ingestion (p \u3c 0.01). In regard to MDA, there was no treatment x timepoint interaction or a significant main effect for treatment but a main effect for time was noted (F= 24.66, p \u3c 0.01) with significantly higher (p \u3c 0.01) MDA levels 2 and 4 hours post ingestion when compared to pre ingestion levels. In terms of GSH, while there was no treatment x timepoint interaction or main effect for time, the main effect for treatment did approach significance (F = 3.67, p = 0.06). There was no treatment x timepoint interaction for TAG nor a main effect for treatment, while there was a significant increase in TAG levels over time noted by a main effect (F = 15.80, p \u3c 0.01) with 2 and 4 hours post ingestion being significantly higher than pre ingestion TAG levels (p \u3c 0.01). Furthermore, with H2O2, a treatment x timepoint interaction (F = 5.94, p \u3c 0.01) was noted. H2O2 levels were significantly lower (p \u3c 0.05) 2 and 4 hours post ingestion following astaxanthin supplementation when compared to the placebo treatment. CONCLUSION: The high fat meal induced significant OS, reflected by increased levels of MDA, AOPP, and H2O2.Despite postprandial hyperlipidemia, astaxanthin was able to significantly decrease H2O2, suggesting astaxanthin is a desirable exogenous antioxidant for mitigating OS

Call for Advanced Training and Diet Programs Due to High Metabolic Demands of Firefighting

Firefighters (FF) require high levels of muscular strength and cardiovascular fitness in order to meet the demands of firefighting. The National Fire Protection Association reported FF in the US are not meeting health and fitness recommendations, which results in poor simulated and on-duty occupational performance. PURPOSE: to examine the demands and stress placed on FF during a series of simulated FF specific physical tasks and identify potential strategies to improve FF specific performance variables. METHODS: Twenty apparently healthy male professional structural FF completed a battery of nine FF specific exercises/movements during a simulated fire ground test (FGT). The exercise included the following: dry hose carry, charged hose carry, low-room search, chainsaw roof walk, forced entry task, ladder carry, stair climb with hose pack, 10 full extension, and victim carry. A familiarization trial was completed prior to testing. Lactate, time to completion, air tank depletion (measured in PSI) and heart rate were recorded. RESULTS: Lactate levels were significantly higher during post-testing compared to resting levels (p \u3c 0.001). Lactate levels were taken before and two-, four-, six, and eight-minutes after the FGT (1.4 ±0.5 mmol/L, 13.2 ±1.7 mmol/L, 13.3 ±2.2 mmol/L, 12.8 ±1.6 mmol/L, 12.2 ±1.9 mmol/L, respectively). Additionally, heart rate (bpm) at timepoints two and three were significantly higher compared to timepoint one (p \u3c 0.001). Heart rate increased significantly from pre FGT 91.2 ±12.4 bpm to 179.2 ±9.5 bpm during the FGT, which was higher than 95% age-predicted max heart rate. In terms of air tank depletion, the FGT resulted in a significant depletion in tank (p \u3c 0.001). A 45-minute air tank depleted approximately 51% within seven minutes. The average FGT time-to-completion was 7.5-minutes. CONCLUSION: Firefighting requires high levels of physical fitness to carry out the job specific tasks. Standardized resistance training programs and dietary interventions are warranted to identify optimal strategies to improve FF specific performance during simulated testing and on-duty tasks. Tactical resistance programming and diet interventions may reduce the impact of physiological and psychological stressors while improving FF ability to meet metabolic and job-specific demands

Aerobic fitness impacts sympathoadrenal axis responses to concurrent challenges

The combination of mental and physical challenges can elicit exacerbated cardiorespiratory (CR) and catecholamine responses above that of a single challenge alone. Purpose This study examined the effects of a combination of acute mental challenges and physical stress on cardiorespiratory and catecholamine responses. Method Eight below-average fitness (LF VO2max = 36.58 +/- 3.36 ml(-1) kg(-1) min(-1)) and eight above-average fitness (HF VO2max = 51.18 +/- 2.09 ml(-1) kg(-1) min(-1)) participants completed an exercise-alone condition (EAC) session consisting of moderate-intensity cycling at 60% VO2max for 37 min, and a dual-challenge condition (DCC) that included concurrent participation in mental challenges while cycling. Result The DCC resulted in increases in perceived workload, CR, epinephrine, and norepinephrine responses overall. HF participants had greater absolute CR and catecholamine responses compared to LF participants and quicker HR recovery after the dual challenge. Conclusion These findings demonstrate that cardiorespiratory fitness does impact the effect of concurrent stressors on CR and catecholamine responses

The metabolic and physiological demands of a simulated fire ground test versus a live-fire training evolution in professional firefighters

International Journal of Exercise Science 16(7): 230-241, 2023. Objective: This study examined the similarities in metabolic and physiological demands of a fire ground test (FGT) and a live fire training evolution. Methods: Twenty-seven firefighters completed either a FGT (n = 13) or a live fire training evolution (n = 14). Salivary samples were collected pre, immediately post, and 30-minutes post FGT and live fire training evolution, and analyzed for cortisol, uric acid, and interleukin-1β (IL-1β). Heart rate (HR) was measured pre- and post-task. Results: Both tasks resulted in significant elevations in cortisol, IL-1β, and HR. Conclusions: Both the FGT and live fire training evolution appear to result in similar metabolic and physiological demands. Further work may expand upon the additional elements (i.e., added heat) of the live fire training evolution. Fire departments may consider incorporating a variety of high intensity training to prepare personnel for these occupational demands

Slow Breathing Reduces Markers of Stress in Response to a Virtual-Reality Active Shooter Training Drill

Law enforcement officers are expected to respond to potential life-threatening scenarios in high stress environments. Acute participation in virtual reality (VR) active shooter scenarios has been shown to increase markers of stress. Tactical occupations (i.e., military, law enforcement personnel) are trained to use slow breathing methods to aid in stress reduction, but there is no known evidence supporting the effectiveness of slow breathing in relation to a VR-active shooter training drill (VR-ASD). PURPOSE: To determine the effects of slow breathing on markers of stress in response to a VR-ASD. METHODS: A parallel between subjects design was used, during which, eighty-one (n=81) subjects performed five minutes of either slow breathing method 1 (SB1), slow breathing method 2 (SB2), or no modified breathing [normal breathing (NB)] immediately pre and post VR-ASD. SB1 (i.e., box breathing) involved a four second inhalation, two second pause, four second exhalation, and a two second pause. SB2 involved a four second inhalation, followed by a two second exhalation. The VR-ASD (~1 minute) included a single gunman and simulated victims. Subjects were fitted with a VR headset and equipped with a Glock 17 training pistol. Salivary samples and heart rate (HR) were collected thirty minutes pre, five minutes pre, five minutes post, and thirty minutes post VR-ASD. Saliva was analyzed for stress markers: α-amylase (AA) and secretory immunoglobulin-A (Sig-A). AA and SIgA were analyzed via 3x4 (treatment x timepoint) factorial ANOVAs. HR was analyzed via 2x4 factorial ANOVA. RESULTS: Both methods of slow breathing (SB1 and SB2) resulted in significantly lower AA concentrations at five (p \u3c 0.001), and thirty-minutes post VR-ASD (SB1: p= 0.008; SB2: p \u3c 0.001) compared to NB. In the NB condition, AA concentrations were significantly elevated five minutes post VR-ASD (p \u3c 0.001) compared to all other timepoints but did not change across time in SB1 or SB2 (p \u3e .05). A significant increase in SIgA concentrations was noted five minutes post VR-ASD compared to all the other time points (p \u3c 0.001), and significantly higher SIgA concentrations were found in the NB compared to SB1 and SB2 (p\u3c0.001). Finally, slow breathing resulted in a significant decrease in HR from pre to post VR-ASD (p \u3c 0.05). CONCLUSION: The VR-ASD resulted in a significant increase in stress markers AA and SIgA. Slow breathing (both SB1 and SB2) prevented a significant increase in AA concentrations and resulted in lower concentrations post VR-ASD. Future studies should investigate the effects of longitudinal participation in slow breathing methods on markers of stress in response to a VR-ASD

Impact of Menstrual Phases on Stress Markers: A Pilot Study

PURPOSE: Previous research has shown that different phases of the menstrual cycle may impact biometrics such as markers of stress and inflammation [e.g., cortisol (CORT), interleukin-6] as well as body composition. However, there is scarce literature regarding markers of stress and oxidative stress such as salivary a-amylase (sAA), immunoglobin-A (SIgA) and uric acid (UA), in relation to the four different menstrual phases. The purpose of this study was to examine the impact of menstrual phases on sAA, CORT, UA and SIgA. METHODS: 21 pre-menopausal women with regular menstrual cycles (n=9) oral contraceptive users (OC) and (n=12) non-oral contraceptive users (non-OC) recorded baseline cycle dates using the Flo Period Tracker appä. Participants began experimental testing after recording baseline dates, consisting of four total sessions with one session occurring during the 1) menses, 2) late follicular, 3) ovulatory and 4) late luteal phase. Salivary markers: CORT, sAA, UA, and SIgA, along with diastolic and systolic blood pressure (BP), total body water (TBW) and body fat percentage (BF%) were recorded during each phase. BF% and TBW were determined via InBody bioelectric-impedance analyzerä. 500uL of saliva was collected, with samples immediately frozen at -80°C until analysis. Saliva samples were centrifuged at 4°C for a duration of 15 minutes at 1500g prior to analysis and duplicated for CORT, sAA, UA and SIgA concentrations. Statistical procedures were conducted via SAS v 9.4 (Cary, NC). One way repeated measures analysis of variance was used to evaluate outcome measures as well as changes in salivary markers and body composition measurements across different menstrual cycle phases. Fisher’s Least Significant Difference test was used to compare means in the instance of a significant main effect (p \u3c 0.05). Partial eta squared (hp2) was run to determine effect size. RESULTS: sAA concentrations were significantly lower during the follicular phase compared menstruation phase (p = 0.006, ηp2 = 0.14). The main effect for SIgA approached significance (p = 0.05). There were no changes in CORT, UA, BF%, TBW or diastolic and systolic blood pressure. CONCLUSION: These findings suggest the menstrual cycle influences sAA concentrations in both OC users and non-OC users. More research needs to be conducted with a larger sample size in order to determine significance of SIgA in relation to menstrual phases

Astaxanthin Reduces Heart Rate and Carbohydrate Oxidation Rates During Exercise in Overweight Individuals

International Journal of Exercise Science 16(2): 252-266, 2023. Astaxanthin (AX) is an antioxidant which may spare endogenous carbohydrates and improve fat oxidation rates, thus improving metabolic flexibility. To date, no studies have attempted to examine the impact of AX in an overweight cohort, whom often suffer from metabolic inflexibility. Nineteen subjects (mean ± SD: age: 27.5 ± 6.3 years; height: 169.7 ± 9.0 cm; body mass: 96.4 ± 17.9 kg; BF%: 37.9 ± 7.0%; BMI: 33.4 ± 5.6 kg/m2; VO2peak: 25.9 ± 6.7 ml·kg−1·min−1) were recruited and supplemented with either 12 mg of AX or placebo (PLA) for 4 weeks. Subjects completed a graded exercise test on a cycling ergometer to examine changes in substrate oxidation rates. A total of 5 stages, each lasting 5 min and resistance increased 15 W each stage, were completed to examine changes in levels of glucose and lactate, fat and carbohydrate (CHO) oxidation rates, heart rate, and rating of perceived exertion (RPE). Although there were no changes found in rates of fat oxidation, blood lactate or glucose, or RPE (all p \u3e 0.05), a significant decrease was observed in CHO oxidation from pre to post supplementation in the AX group only. Further, the AX group demonstrated a 7% decrease in heart rate across the graded exercise test. These findings suggest that 4 weeks of AX supplementation may offer some cardiometabolic benefits to overweight individuals, and be a favorable supplement for these individuals beginning an exercise program

Predictors of Cardiometabolic Disease Risk Factors in Professional Firefighters

The leading cause of mortality (~50% of deaths) among on-duty firefighters is sudden cardiac death. Firefighters with adequate cardiorespiratory fitness levels (among other muscular fitness metrics) and lower body fat percentage (BF%) are likely to better combat on-duty cardiac events and cardiovascular disease (CVD) risk. Individuals with higher VO2max values may be at lower risk noted by lower oxidative stress and inflammatory biomarkers, which may be more ideal predictors of CVD risk compared to traditional biomarkers (i.e., blood glucose and lipids) among the fire community; however, more research is needed to elucidate. PURPOSE: This study examined the relationship between fitness metrics, body fat percentage, and traditional and non-traditional biomarkers among professional firefighters. METHODS: Ninety-eight professional, male firefighters (age = 36.26 ± 9.08 yrs; height = 179.53 ± 7.06 cm; waist circumference = 37.99 ± 4.13 cm; BF% = 24.39 ± 5.21; years of experience = 11.81 ± 8.00 yrs) from a local fire department were studied VO2max was estimated from total treadmill exercise time using the Foster equation.. Fitness metrics including muscular strength, endurance, and power variables were also measured. Fasted blood samples were analyzed for concentrations of lipids, glucose, insulin resistance (HOMA-IR), advanced oxidation protein products (AOPP), and ultra-sensitive C-reactive protein (CRP). To assess the relationship between fitness metrics and AOPP, CRP, and HOMA-IR, ordinary least square regression analyses were used. RESULTS: VO2max values were inversely (p \u3c 0.05) related to AOPP, HOMA-IR, and CRP. Waist circumference was positively correlated to AOPP concentrations and HOMA-IR, while increased BF% was significantly related to increased CRP concentrations. CONCLUSION: High VO2max values were significantly related to lower AOPP, CRP, and HOMA-IR. Additionally, high waist circumference and BF% values were related to increases in oxidative stress, inflammation, and insulin resistance. Firefighters are encouraged to maintain high cardiorespiratory fitness (VO2max) and lower BF% to reduce CVD and, ultimately, on-duty sudden cardiac death risk

Firefighters Versus Law Enforcement Officers: A Comparison Of Cardiovascular Disease Risk

Firefighters (FF) and law enforcement officers (LEO) have heightened cardiovascular disease (CVD) risk due to the stressful nature of their occupations. Data suggest that 45% of on-duty FF fatalities are related to CVD, while LEO have a 1.7 times higher CVD prevalence compared to the general public. To our knowledge, studies comparing FF to LEO, in terms of CVD risk factors, have not been published. This information is necessary to better understand differences in occupational disease risk, as well as to help bridge the gap between stress and CVD markers. PURPOSE: To compare CVD risk biomarkers, fitness, and body composition between career FF and LEO. METHODS: Ninety-eight career, structural male FF (age = 35.1±9.6 yrs; weight = 94.3±15.4 kg; height = 178.4±13.2 cm) and seventy-three career male and female LEO (age = 41.4±9.0 yrs; weight = 92.3±16.8 kg; height = 179.6±8.1 cm) from local fire and police departments were studied. Participants completed a maximal cardiopulmonary exercise test (CPXT), where VO2max was estimated from the Foster equation. Fasted blood samples were collected to assess biomarkers of CVD risk: advanced oxidation protein products (AOPP) and cortisol. Dual-energy X-ray absorptiometry was used to assess body composition and waist and hip measures were taken. Shapiro-Wilk Test was used to assess normality. Independent sample T-tests or non-parametric Mann-Whitney U tests (if normality was violated) were used to assess differences in CVD risk biomarkers, fitness, and body composition between the FF and LEO. Effect sizes were calculated as Cohen’s d (i.e., small [0.2-0.5], medium [0.5-0.8], large [\u3e0.8]). RESULTS: Firefighters had higher (p\u3c0.05) CPXT exercise times (FF: 10.9±1.6 min; LEO: 10.3±2.0 min; d=0.366) compared to LEO. While not statistically significant (p=0.64), FF had higher VO2max values (FF: 38.2±6.6 ml/kg/min; LEO: 36.2±6.2 ml/kg/min; d=0.306). Firefighters also had higher (p\u3c0.05) AOPP (FF: 134.8±90.1 mM; LEO: 106.8±67.6 mM; d=0.342), blood cortisol (FF: 14.2±5.0 mg/dL; LEO: 12.5±5.6 mg/dL; d=0.325), and waist-to-hip ratios (FF: 0.95±0.06; LEO: 0.89±0.08; d=0.792). CONCLUSION: These findings suggest that while FF demonstrated greater CPXT time-to-exhaustion they also expressed greater levels of stress and risk for CVD compared to LEO