Menthol alleviates post-race elevations in muscle soreness and metabolic and respiratory stress during running

PURPOSE

We evaluated (1) whether participating in middle- and long-distance running races augments muscle soreness, oxygen cost, respiration, and exercise exertion during subsequent running, and (2) if post-race menthol application alleviates these responses in long-distance runners.

METHODS

Eleven long-distance runners completed a 1500-m race on day 1 and a 3000-m race on day 2. On day 3 (post-race day), either a 4% menthol solution (Post-race menthol) or a placebo solution (Post-race placebo) serving as a vehicle control, was applied to their lower leg skin, and their perceptual and physiological responses were evaluated. The identical assessment with the placebo solution was also conducted without race participation (No-race placebo).

RESULTS

The integrated muscle soreness index increased in the Post-race placebo compared to the No-race placebo (P < 0.001), but this response was absent in the Post-race menthol (P = 0.058). Oxygen uptake during treadmill running tended to be higher (4.3%) in the Post-race placebo vs. No-race placebo (P = 0.074). Oxygen uptake was 5.4% lower in the Post-race menthol compared to the Post-race placebo (P = 0.018). Minute ventilation during treadmill running was 6.7-7.6% higher in the Post-race placebo compared to No-race placebo, whereas it was 6.6-9.0% lower in the Post-race menthol vs. Post-race placebo (all P ≤ 0.001). The rate of perceived exertion was 7.0% lower in the Post-race menthol vs. Post-race placebo (P = 0.007).

CONCLUSIONS

Middle- and long-distance races can subsequently elevate muscle soreness and induce respiratory and metabolic stress, but post-race menthol application to the lower legs can mitigate these responses and reduce exercise exertion in long-distance runners.

GH and IGF-1 in skin interstitial fluid and blood are associated with heat loss responses in exercising young adults

PURPOSE

Sweat glands and cutaneous vessels possess growth hormone (GH) and insulin-like growth factor 1 (IGF-1) receptors. Here, we assessed if exercise increases GH and IGF-1 in skin interstitial fluid, and whether baseline and exercise-induced increases in GH and IGF-1 concentrations in skin interstitial fluid/blood are associated with heat loss responses of sweating and cutaneous vasodilation.

METHODS

Sixteen young adults (7 women) performed a 50-min moderate-intensity exercise bout (50% VO2peak) during which skin dialysate and blood samples were collected. In a sub-study (n = 7, 4 women), we administered varying concentrations of GH (0.025-4000 ng/mL) and IGF-1 (0.000256-100 µg/mL) into skin interstitial fluid via intradermal microdialysis. Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC) were measured continuously for both studies.

RESULTS

Exercise increased sweating and CVC (both P < 0.001), paralleled by increases of serum GH and skin dialysate GH and IGF-1 (all P ≤ 0.041) without changes in serum IGF-1. Sweating was positively correlated with baseline dialysate and serum GH levels, as well as exercise-induced increases in serum GH and IGF-1 (all P ≤ 0.044). Increases in CVC were not correlated with any GH and IGF-1 variables. Exogenous administration of GH and IGF-1 did not modulate resting sweat rate and CVC.

CONCLUSION

(1) Exercise increases GH and IGF-1 levels in the skin interstitial fluid, (2) exercise-induced sweating is associated with baseline GH in skin interstitial fluid and blood, as well as exercise-induced increases in blood GH and IGF-1, and (3) cutaneous vasodilation during exercise is not associated with GH and IGF-1 in skin interstitial fluid and blood.

Impact of curcumin supplementation on exercise performance and muscle damage after a soccer match: a double-blind placebo-controlled cross-over study

PURPOSE

Curcumin ingestion can mitigate muscle damage, soreness, and inflammation following a laboratory-based eccentric exercise. Similar effects were observed in recent field-based studies wherein responses were evaluated after a soccer match. However, various potential confounding factors, such as matching opponent skill levels and daily training conditions, may have influenced the outcomes. In the present study, we investigated whether curcumin intake ameliorates changes in muscle damage markers following a soccer match while controlling for the potential confounding factors.

METHODS

Fifteen collegiate athletes were tested in a randomized, double-blind, cross-over manner. They were recruited from the same college soccer team and thus followed the same daily training regimen and competition levels. Furthermore, athletes positioning during matches were counterbalanced. They consumed either 180 mg/day of curcumin or a placebo starting 1 h before the match and continuing for 2 days after a match (two 45-min plays and a 15-min half-time). Muscle soreness, jump performance (including countermovement jump and rebound jump index), and inflammatory and muscle damage markers (high-sensitive C-reactive protein, serum creatine kinase activity, and urinary N-terminal fragment of titin concentration) were evaluated before and after the match. The washout period between matches was set at 1 week.

RESULTS

After the match, all markers showed similarity between the placebo and curcumin conditions (all P > 0.208).

CONCLUSION

These findings indicate that ingesting 180 mg/day of curcumin may not expedite recovery from muscle damage elicited by soccer matches in collegiate soccer players.

Comparison of Bioelectrical Impedance Indices for Skeletal Muscle Mass and Intracellular Water Measurements of Physically Active Young Men and Athletes

BACKGROUND

Bioelectrical impedance analysis (BIA) is a minimally invasive, safe, easy, and quick technology used to determine body composition.

OBJECTIVES

We compared the relationship among impedance indices obtained using single-frequency BIA, multi-frequency BIA, bioelectrical impedance spectroscopy (BIS), and skeletal muscle mass (SMM) of physically active young men and athletes using the creatine (methyl-d3) dilution method. We also compared the SMM and intracellular water (ICW) of athletes and active young men measured using a reference stable isotope dilution and BIS method, respectively.

METHODS

We analyzed data from 28 men (mean age, 20 ± 2 y) who exercised regularly. Single-frequency BIA at 5 kHz and 50 kHz (R5 and R50), multi-frequency BIA (R250-5), and BIS (RICW) methods of determining the SMM were compared. The deuterium and sodium bromide dilution methods of obtaining the total body water, ICW, and extracellular water measurements were also used, and the results were compared to those acquired using bioimpedance methods.

RESULTS

The correlation coefficients between SMM and L2/R5, L2/R50, L2/R250-5, and L2/RICW were 0.738, 0.762, 0.790, and 0.790, respectively (P < 0.01). The correlation coefficients between ICW and L2/R5, L2/R50, L2/R250-5, and L2/RICW were 0.660, 0.687, 0.758, and 0.730, respectively (P < 0.001). However, the correlation coefficients of L2/R50, L2/R250-5, and L2/RICW for SMM and ICW were not significantly different.

CONCLUSIONS

Our findings suggest that single-frequency BIA at L2/R50, multi-frequency BIA, and BIS are valid for assessing the SMM of athletes and active young men. Additionally, we confirmed that the SMM and ICW were correlated with single-frequency BIA, multi-frequency BIA, and BIS. Bioimpedance technologies may be dependable and practical means for assessing SMM and hydration compartment status of active young adult males; however, cross-validation is needed.

Galanin receptors modulate cutaneous vasodilation elicited by whole-body and local heating but not thermal sweating in young adults

Galanin receptor subtypes GAL₁, GAL₂, and GAL₃ are involved in several biological functions. We hypothesized that 1) GAL₃ receptor activation contributes to sweating but limits cutaneous vasodilation induced by whole-body and local heating without a contribution of GAL₂; and 2) GAL₁ receptor activation attenuates both sweating and cutaneous vasodilation during whole-body heating. Young adults underwent whole-body (n = 12, 6 females) and local (n = 10, 4 females) heating. Forearm sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC; ratio of laser-Doppler blood flow to mean arterial pressure) were assessed during whole-body heating (water-perfusion suit circulated with warm (35 °C) water), while CVC was also assessed by local forearm heating (33 °C-39 °C and elevated to 42 °C thereafter; each level of heating maintained for ∼30 min). Sweat rate and CVC were evaluated at four intradermal microdialysis forearm sites treated with either 1) 5% dimethyl sulfoxide (control), 2) M40, a non-selective GAL₁ and GAL₂ receptor antagonist, 3) M871 to selectively antagonize GAL₂ receptor, or 4) SNAP398299 to selectively antagonize GAL₃ receptor. Sweating was not modulated by any GAL receptor antagonist (P > 0.169), whereas only M40 reduced CVC (P ≤ 0.003) relative to control during whole-body heating. Relative to control, SNAP398299 augmented the initial and sustained increase in CVC during local heating to 39 °C, and the transient increase at 42 °C (P ≤ 0.028). We confirmed that while none of the galanin receptors modulate sweating during whole-body heating, GAL₁ receptors mediate cutaneous vasodilation. Further, GAL₃ receptors blunt cutaneous vasodilation during local heating.

Serum, interstitial, and sweat ATP in humans exposed to heat stress: insights into roles of ATP in the heat loss responses

Hyperthermia increases intravascular ATP and is associated with greater hyperthermia-induced cutaneous vasodilation. Hyperthermia may also increase skin interstitial fluid ATP thereby activating cutaneous vascular smooth muscle cells and sweat glands. We evaluated the hypothesis that whole-body heating would increase skin interstitial fluid ATP, and this response would be associated with an increase in cutaneous vasodilation and sweating. Nineteen (8 females) young adults underwent whole-body heating using a water-perfusion suit to increase core temperature by ≥1°C during which time cutaneous vascular conductance (CVC, ratio of laser-Doppler blood flow to mean arterial pressure) and sweat rate (ventilated capsule technique) were measured at four forearm skin sites to minimize between-site variations. Dialysate from the skin sites were collected via intradermal microdialysis. Heating increased serum ATP, CVC, and sweat rate (all P ≤ 0.031). However, heating did not modulate dialysate ATP (median, baseline vs. end-heating: 2.38 vs. 2.70 nmol/ml) (P = 0.068), though the effect size was moderate (Cohen's d = 0.566). While the heating-induced increase in CVC was not correlated with changes in serum ATP (r = 0.439, P = 0.060), we observed a negative correlation (r_s = -0.555, P = 0.017) between dialysate ATP and CVC. We did not observe a significant correlation between the heating-induced sweating and serum, dialysate, or sweat ATP (r_s = 0.091 to -0.322, all P ≥ 0.222). Altogether, we showed that passive heating increases ATP in blood and possibly skin interstitial fluid, with the latter potentially blunting cutaneous vasodilation. However, ATP does not appear to modulate sweating. This article is protected by copyright. All rights reserved.

Thermal stress, hydration, and salivary and respiratory stress markers in curling players performing a match in the cold

Curling is a target-based team sport played in a cold environment. The type of stress curling players face during a curling match remains to be determined. In the present study, 16 Japanese curling players performed a practice curling match (6 ends lasting 90 min), wherein the following parameters were documented: core and skin temperatures, heart rate, thermal sensation and comfort, urine specific gravity, body fluid loss, salivary cortisol, α-amylase activity, salivary secretory immunoglobulin A (SIgA) levels, and fractionated exhaled nitric oxide (FeNO, a respiratory stress marker) levels. Pre-match resting core temperature was 37.24 ± 0.31 °C, which increased up to 37.73 ± 0.41 °C during the match (P<0.001). Facial skin temperatures decreased after the match (all P≤0.015), whereas finger skin temperatures remained unchanged (P≥0.375). Thermal discomfort increased following the match but thermal sensation remained unchanged. Following the match, players lost 0.29 ± 0.15 L body fluid (sweat, respiratory evaporation, and urine), which was nearly compensated by fluid ingestion of 0.22 ± 0.13 L (P=0.119). Nevertheless, urine specific gravity increased from 1.021 ± 0.010 to 1.024 ± 0.008 after the match (P=0.012), with 31% and 50% players being dehydrated at pre- and post-match, respectively. Salivary cortisol decreased (P<0.001) after the match without changes in salivary SIgA, α-amylase activity, and FeNO (all P≥0.113). Therefore, during a curling match, the core temperature and thermal discomfort increase, whereas the face skin temperature decreases. Additionally, players may undergo dehydration before the match, which could be exacerbated after the match.

Skeletal muscle mass can be estimated by creatine (methyl-d3) dilution and is correlated with fat-free mass in active young males

BACKGROUND

Assessing whole-body skeletal muscle mass (SMM) and fat-free mass (FFM) is essential for the adequate nutritional management and training evaluation of athletes and trained individuals. This study aimed to determine the relationship between SMM assessed using the creatine (methyl-d₃) dilution (D₃-creatine) method and SMM estimated by whole-body magnetic resonance imaging (MRI) in healthy young men undergoing exercise training. Additionally, we examined the association between FFM measured using the four-component (4C) method (FFM_4C) and the total body protein value estimated using 4C (TBpro_4C).

METHODS AND RESULTS

We analyzed the data of 29 males (mean age, 19.9 ± 1.8 years) who exercised regularly. SMM measurements were obtained using the D₃-creatine method (SMM_D3-creatine) and MRI (SMM_MRI). The SMM_D3-creatine adjusted to 4.3 g/SMM kg was significantly higher than SMM_MRI (p < 0.01). The fit of the creatine pool size compared with SMM_MRI was 5.0 g/SMM_MRI kg. SMM_MRI was significantly correlated with both SMM_D3-creatine adjusted to 4.3 g/kg and 5.1 g/kg. TBpro_4C was significantly lower than SMM_MRI (p < 0.01). Contrastingly, FFM_4C was significantly higher than SMM_MRI (p < 0.01).

CONCLUSIONS

SMM_D3-creatine adjusted to 4.3 g/SMM kg-a previously reported value-may differ for athletes and active young males. We believe that a value of 5.0-5.1 g/SMM kg better estimates the total muscle mass in this population. Traditional FFM estimation highly correlates with SMM_MRI in well-trained young males, and the relationships appear strong enough for total body protein or SMM to be estimated through the FFM value.

Preexercise High-Fat Meal Following Carbohydrate Loading Attenuates Glycogen Utilization During Endurance Exercise in Male Recreational Runners

ABSTRACT

Iwayama, K, Tanabe, Y, Yajima, K, Tanji, F, Onishi, T, and Takahashi, H. Preexercise high-fat meal following carbohydrate loading attenuates glycogen utilization during endurance exercise in male recreational runners. J Strength Cond Res 37(3): 661-668, 2023-This study aimed to investigate whether one preexercise high-fat meal can increase glycogen conservation during endurance exercise, as compared with one preexercise high-carbohydrate meal. Ten young male recreational runners (22.0 ± 0.6 years; 171.3 ± 0.9 cm; 58.3 ± 1.9 kg; maximal oxygen uptake [V̇ o2 max], 62.0 ± 1.6 ml·kg -1 ·min -1 ) completed 2 exercise trials after high-carbohydrate loading: eating a high-carbohydrate (CHO; 7% protein, 13% fat, 80% carbohydrate) meal or eating a high-fat (FAT; 7% protein, 42% fat, 52% carbohydrate) meal 3.5 hours before exercise. The order of the 2 trials was randomized, and the interval between trials was at least 1 week. The experimental exercise consisted of running on a treadmill for 60 minutes at 95% of each subject's lactate threshold. Muscle and liver glycogen content were assessed using noninvasive carbon magnetic resonance spectroscopy before the experimental meal as well as before and after exercise; respiratory gases were measured continuously during exercise. The respiratory exchange ratio during exercise was statistically lower in the FAT trial than in the CHO trial ( p < 0.01). In addition, muscle ( p < 0.05) and liver ( p < 0.05) glycogen utilization during exercise was less in the FAT trial than in the CHO trial. Therefore, one high-fat meal following carbohydrate loading reduced muscle and liver glycogen use during the 60-minute exercise. These results suggest that this dietary approach may be applied as a strategy to optimize energy utilization during endurance exercise.

Perilla seed oil improves bone health by inhibiting bone resorption in healthy Japanese adults: A 12-month, randomized, double-blind, placebo-controlled trial

Accumulating evidence suggests the beneficial effect of omega-3 polyunsaturated fatty acids (PUFAs) on bone mineral density (BMD). However, the effects of perilla (Perilla frutescens) seed oil (PO), a rich source of α-linoleic acid (LNA), on human bone have not yet been elucidated. This randomized, double-blind, placebo-controlled trial investigated the effects of long-term PO intake on bone health in Japanese adults. After screening for eligibility, 52 participants (mean age 54.2 ± 6.4 years) were randomly assigned to placebo (n = 25) and PO (n = 27) groups, which received 7.0 ml of olive oil and PO daily, respectively. At baseline and 12-month, quantitative ultrasound of the right calcaneus was measured with an ultrasound bone densitometer and percentage of the Young Adult Mean (%YAM) was calculated. Serum levels of tartrate-resistant acid phosphatase 5b (TRACP-5b), and bone alkaline phosphatase (BALP) were evaluated. In addition, PUFA levels in the erythrocyte plasma membrane (RBC-PM), serum biological antioxidant potential (BAP), and diacron reactive oxygen metabolites (d-ROM) were evaluated. Compared with the placebo group, %YAM levels increased and serum TRACP-5b levels decreased significantly in the PO group at 12-month, while serum BALP levels remained unchanged. Moreover, RBC-PM LNA levels and BAP/d-ROM ratios increased significantly in the PO compared with the placebo group. These results suggest that long-term PO intake may improve age-related BMD decline by suppressing bone resorption and increasing LNA levels.

Perilla frutescens seed oil combined with Anredera cordifolia leaf powder attenuates age-related cognitive decline by reducing serum triglyceride and glucose levels in healthy elderly Japanese individuals: a possible supplement for brain health

We have shown that Anredera cordifolia extract improves learning and memory in a senescence-accelerated mouse model, and that α-linolenic acid (ALA)-rich Perilla frutescens seed oil (PO) improves brain function in healthy Japanese adults and elderly individuals. Herein, we present a 12-month, randomised, double-blind, parallel-armed intervention trial examining the effects of PO supplementation alone or in combination with A. cordifolia leaf powder on brain function in healthy elderly Japanese individuals. Participants were randomly divided into two groups: the PO group received 1.47 mL PO (0.88 g ALA) daily via soft gelatine capsules, and the POAC group received 1.47 mL PO and 1.12 g A. cordifolia leaf powder (1.46 mg vitexin and 1.12 mg adenosine) daily. After 12 months of intervention, the POAC group showed generally higher cognitive index scores than the PO group. The beneficial effects of combined supplementation on cognitive function were associated with increased ALA and eicosapentaenoic acid levels in red blood cell plasma membranes, increased serum biological antioxidant potential, and decreased serum triglyceride, glucose, and N-(epsilon)-carboxymethyl-lysine (CML), an advanced glycation end-product and biochemical marker of oxidative stress levels. The effects of combined supplementation on cognitive function also showed a significant negative correlation with serum CML levels after 12 months of intervention. Our findings suggest that combined long-term supplementation with PO and A. cordifolia more effectively ameliorates age-related cognitive decline than PO alone. These findings may serve as a basis for the development of new supplements for brain health. Clinical Trial Registry, UMIN000040863.

Perilla seed oil in combination with the nobiletin-rich ponkan powder enhances cognitive function in healthy elderly Japanese individuals: Possible supplement for brain health in the elderly

Perilla (Perilla frutescens) seed oil (PO), rich in α-linolenic acid (ALA), can improve cognitive function in healthy elderly Japanese people. Here, supplements containing either PO alone or PO with nobiletin-rich...

Intake of Docosahexaenoic Acid-Enriched Milk Beverage Prevents Age-Related Cognitive Decline and Decreases Serum Bone Resorption Marker Levels

The pathogenic mechanism of dementia is still unknown, and the fundamental treatment remains to be established. Thus, there is growing interest in preventing dementia through diet. One of the functional ingredients attracting attention is docosahexaenoic acid. We conducted a 12-month, randomized, double-blind, placebo-controlled clinical trial in healthy elderly Japanese individuals with a Mini-Mental State Examination score of 28 or higher at baseline using a docosahexaenoic acid-enriched milk beverage containing 297 mg docosahexaenoic acid and 137 mg eicosapentaenoic acid. Consumption of a docosahexaenoic acid-enriched milk beverage increased the fatty acid levels of docosahexaenoic acid and eicosapentaenoic acid in erythrocyte membranes, which was the primary outcome of this study. Moreover, intake of this beverage prevented age-related cognitive decline and decreased serum bone resorption marker levels. Our data demonstrate that, even at a low dose, long-term daily intake of docosahexaenoic acid prevents dementia and may show beneficial effect on bone health.

Diurnal variations in muscle and liver glycogen differ depending on the timing of exercise

It has been suggested that glycogen functions not only in carbohydrate energy storage, but also as molecular sensors capable of activating lipolysis. This study aimed to compare the variation in liver and muscle glycogen during the day due to different timing of exercise. Nine healthy young men participated in two trials in which they performed a single bout of exercise at 70% of their individual maximal oxygen uptake for 60 min in the post-absorptive (morning) or post-prandial (afternoon) state. Liver and muscles glycogen levels were measured using carbon magnetic resonance spectroscopy (13C MRS). Diurnal variations in liver and muscle glycogen compared to baseline levels were significantly different depending on the timing of exercise. The effect of the timing of exercise on glycogen fluctuation is known to be related to a variety of metabolic signals, and the results of this study will be useful for future research on energy metabolism.

Validation of skeletal muscle mass estimation equations in active young adults: A preliminary study

We analyzed the validity of the estimation equations for skeletal muscle mass (SMM) using mass of appendicular lean soft tissue (ALST), evaluated by dual-energy X-ray absorptiometry (DXA), in healthy young males undergoing training, and compared it with the results obtained using whole-body magnetic resonance imaging (MRI). We hypothesized that a novel variable, that is, trunk and trunk-to-appendicular ratio of lean soft tissues (trunk/ALST), would be useful in reducing estimation errors in athletes or physically active participants. We analyzed the data of 30 participants (mean age 19.9 ± 1.8 years). SMM was measured using whole-body MRI, while mass of trunk and ALST was assessed using DXA. Three previously utilized estimation equations were retrieved from the literature and used for comparison. The estimated SMM values using previous equations highly correlated with measured SMM, which was determined by MRI, but the mean estimated SMM values were significantly lower than the measured-SMM values. Stepwise regression analysis revealed that mass of ALST, trunk/ALST ratio, and percent body fat were significant predictors of SMM and were incorporated as the new suggested variables. This equation accounted for 90.3% of the variance in SMM. While the previous equations' estimated SMM correlated with measured-SMM in participants with trunk/ALST ratios ≤1.05, they underestimated SMMs in those with trunk/ALST ratios >1.05. The present study confirms that the previously used equations underestimate the actual SMM, particularly in participants with high trunk/ALST ratios (>1.05). The current equation may be used in healthy and active young males, including athletes, as a preliminary tool.

Anredera cordifolia extract enhances learning and memory in senescence-accelerated mouse-prone 8 (SAMP8) mice

Learning and memory impairment may result from age-related decline in synaptic plasticity-related proteins in the hippocampus. Therefore, exploration of functional foods capable of ameliorating memory and cognition decline is an interesting endeavor in neuroscience research. We report the effects of Anredera cordifolia (AC) extract on learning and memory deficits in a senescence-accelerated mouse-prone 8 (SAMP8) mouse model, which demonstrate age-related memory deficits and related pathological changes in the brain. After 8 weeks of oral administration of AC extract, the mice were trained in the Novel Object Recognition (NOR) task, and after 7 more weeks, in the Morris Water Maze (MWM) task. Following the completion of behavioral testing, the blood biochemistry parameters, the hippocampal levels of brain-derived neurotropic factor (BDNF), PSD95, and NR2A, and the p-cAMP-response element binding (p-CREB)/CREB ratio were measured. The AC-treated group spent more time exploring the novel objects in the NOR task, and showed faster acquisition and better retention in the MWM task than the negative control (CN) group. In addition, AC enhanced the levels of the aforementioned neuronal plasticity-related proteins, and did not affect the blood biochemistry parameters. Therefore, our data suggest that the AC extract may improve learning and memory without causing any noticeable side effects in the body.

Effects of 6-(Methylsulfinyl)hexyl Isothiocyanate Ingestion on Muscle Damage after Eccentric Exercise in Healthy Males: A Pilot Placebo-Controlled Double-Blind Crossover Study

An animal study demonstrated that 6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC), a major bioactive compound in Japanese pungent spice wasabi, has an action of inhibiting the activation of calpain-1 (a protease). Increases in calpain activity can cause continual strength loss after eccentric exercise. It remains to be determined in humans whether 6-MSITC intake would modulate calpain and/or muscle damage responses after eccentric exercise. We performed a randomized, double-blind, crossover design study wherein eight healthy young males were randomly assigned to ingest 9 mg/day of 6-MSITC or placebo from 1 day before exercise to 4 days after exercise (30 maximal isokinetic eccentric contractions of the elbow flexors using an isokinetic dynamometer). Calpain-1 concentration, inflammatory and muscle damage markers (creatine kinase activity, urinary titin concentration, muscle strength, range of motion, muscle soreness and transverse relaxation time) were assessed. Plasma calpain-1 concentration after eccentric exercise was similar between the placebo- and 6-MSITC-treated conditions. All muscle damage and inflammatory markers were not affected by 6-MSITC relative to those in the placebo-treated condition. Our results suggest that 6-MSITC has no effect on plasma calpain-1 concentration and muscle damage and inflammatory markers measured after eccentric exercise.

Urinary N-terminal fragment of titin: A surrogate marker of serum creatine kinase activity after exercise-induced severe muscle damage

We aimed to evaluate whether changes in the noninvasively assessed urinary N-terminal fragment of titin (U-titin) concentration may be associated with those of serum creatine kinase (CK) activity, transverse relaxation time (T₂), maximal voluntary contraction (MVC) torque, range of motion (ROM), and muscle soreness, following high-intensity eccentric exercise. Twenty-eight healthy young men performed 30 maximal isokinetic (120°/s) eccentric elbow flexor contractions using an isokinetic dynamometer. U-titin concentration, serum CK activity, T₂, MVC torque, ROM, and muscle soreness were measured before and after a maximum of 4 days. Both U-titin concentration and serum CK activity increased post-exercise in a similar manner, though the former elevated slightly earlier (p < 0.05). The peak values of log U-titin concentration following eccentric exercise were strongly correlated with those of log serum CK activity (r = 0.90, p < 0.05) and T₂ (r = 0.84, p < 0.05). There were moderate correlations between peak values of U-titin concentration and those of MVC torque (r = 0.69, p < 0.05) and ROM decline rate (r = 0.45, p < 0.05). These results suggest that in healthy young men, the non-invasive marker, U-titin, may be used as a serum CK surrogate following exercise-induced severe muscle damage.

Urinary N-Terminal Fragment of Titin Reflects Muscle Damage After a Soccer Match in Male Collegiate Soccer Players

ABSTRACT

Tanabe, Y, Shimizu, K, Kondo, E, Yasumatsu, M, Nakamura, D, Sagayama, H, and Takahashi, H. Urinary N-terminal fragment of titin reflects muscle damage after a soccer match in male collegiate soccer players. J Strength Cond Res 35(2): 360-365, 2021-Previous studies have demonstrated that noninvasive urinary N-terminal fragment of titin (U-titin) concentration highly correlates with serum creatine kinase (CK) activity, a classic invasive muscle damage marker. This finding indicates that U-titin could be used to estimate muscle damage. However, these results were achieved using a laboratory-based eccentric exercise model. Therefore, it remains unclear whether U-titin is useful for evaluating muscle damage occurring in field sports events. As a result, we evaluated whether U-titin concentration closely relates to serum CK activity after a soccer match. Seventeen collegiate soccer players (age: 20 ± 1 year; height: 172 ± 6 cm; body mass: 65 ± 5 kg; Yo-Yo intermittent recovery test level 2, 1,135 ± 196 m) completed a test match (2 halves of 45 minutes separated by 15 minutes of normal half-time). U-titin concentration, serum CK activity, countermovement jump performance, and muscle soreness were assessed 2 hours before the match and 30 minutes, 24 hours, and 48 hours after the match. U-titin concentrations and CK activity similarly increased at 24 hours and returned to the baseline value at 48 hours after the match. Moreover, the percentage of changes in U-titin concentration from baseline after the match significantly and positively correlated with serum CK activity (r = 0.82, p < 0.05). These results suggest that the noninvasive marker U-titin can be used to assess muscle damage conditions in field sports events, such as soccer matches.

Different degree of intervention in 6-month weight-loss support and arterial stiffness: Secondary analysis of a randomized controlled trial

BACKGROUND AND AIMS

Weight reduction by lifestyle modification (i.e., low-calorie diet and/or exercise) decreases arterial stiffness in overweight or obese individuals. We previously demonstrated that weight loss differs depending on the degree of intervention in weight-loss support in a randomized controlled trial (UMIN000001259). However, the effect of different degrees of intervention on arterial stiffness remains unclear.

METHODS AND RESULTS

A total of 188 middle-aged men and women with overweight or obesity (51 ± 7 years, BMI: 29.0 ± 3.2 kg/m²) participated in the 6-month trial wherein they were assigned to a low (LI, n = 63), moderate (MI, n = 62), or high intensive intervention (HI, n = 63) group. Initially, one motivational lecture on weight loss was provided to all three groups, whereas educational materials (textbooks, notebooks, and a pedometer) were provided to groups MI and HI. Additionally, the HI group participated in a series of group-based sessions. Body weight and arterial stiffness assessed by brachial-ankle pulse wave velocity (baPWV) were measured at 0, 3, and 6 months. Six-month weight loss was greater in the order of HI, MI, and LI groups. The interventions reduced baPWV in all groups, and the reduction was not significantly different among the groups (114.3 ± 16.3, 82.6 ± 15.2, and 98.8 ± 90.4 cm/s, respectively).

CONCLUSION

In overweight or obese individuals, different degrees of intervention in weight-loss support affect body weight; however, the extent to which arterial stiffness improves does not differ among support programs.

Effect of PM2.5 for hospitalization of cardiovascular diseases and medical expenses by age group: a nationwide study from the Japanese Registry Of All cardiac and vascular Diseases (JROAD)

Introduction

Although particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5) exposure influences cardiovascular events, there is limited knowledge how PM2.5 exposure is associated with cardiovascular hospitalization in Japan.

Purpose

We tested the hypothesis that PM2.5 exposure was related to the number of cardiovascular hospitalizations, hospitalization period, and medical expenses.

Methods

We included 835,405 subjects who were admitted to acute care hospitals in Japan. We classified PM2.5 exposure concentration into quintile groups (from low to high in the order of “PM-1” to “PM-5” group). Multilevel mixed-effects Poisson and linear regression analysis were used to estimate the association of PM2.5 exposure concentration with the cardiovascular hospitalization events, duration and medical expenses. We also analyzed those factors classified by age.

Results

PM-2, 3, 4, 5 group were positively related to the number of cardiovascular hospitalization events compared with PM-1 group (Table 1). PM-3, 4, 5 group were positively associated with a 0.018, 0.029, and 0.029 (all p&lt;0.001) of the difference of log cardiovascular hospitalization period compared with PM-1 group (p for trend &lt;0.001). These groups were also positively associated with a 0.016, 0.023, and 0.021 (all p&lt;0.001) of the difference of log medical expenses compared with PM-1 group (p for trend &lt;0.001). Analyzed by age group, hospitalization duration was longer (p&lt;0.05) and medical expenses was lower (p&lt;0.05) significantly in super-aging group (over 90 years old) than the group under 64 years old (Figure 1).

Conclusions

PM2.5 exposure concentration has harmful effect on not only cardiovascular events but cardiovascular hospitalization period and medical expenses due to big-data in Japan. Medical costs were kept low in comparison with their hospitalization period in subjects over 90 years old.

Figure 1

Funding Acknowledgement

Type of funding source: None

Low caffeine dose improves intermittent sprint performance in hot and humid environments

While the effects of caffeine have been evaluated in relation to endurance exercise, few studies have assessed the ergogenic effects of low caffeine doses on intermittent exercise performance in hot and humid environments. Thus, we aimed to determine the effects of low-dose caffeine supplementation on intermittent exercise performance under these conditions. Eight male soccer players (age, 19.9 ± 0.3 years; height, 173.7 ± 6.3 cm; body mass, 65.1 ± 5.5 kg; V˙O₂max, 50.0 ± 3.1 mL ⋅ kg^-1⋅ min^-1) participated in this double-blind, randomized, cross-over study. Caffeine was orally administered at 60 min before exercise (dosage, 3 mg ⋅ kg^-1). The participants completed a 90-min intermittent sprint cycling protocol under two conditions (after receiving caffeine and placebo) at 32 °C and at 70% relative humidity. A significant improvement in the total amount of work was observed in the caffeine condition compared to the placebo condition (155.0 ± 15.8 vs 150.8 ± 14.5 kJ, respectively; p < 0.05, d = 0.28). In contrast, the rectal temperature measured at the end of exercise showed no significant difference between the conditions (38.9 ± 0.4 °C and 38.7 ± 0.5 °C in the caffeine and placebo conditions, respectively; p > 0.05, d = 0.57). Other thermal responses, such as the mean skin temperature, heart rate, or sweat volume, were not significantly different between these conditions. These results suggested that a low caffeine dose improved the intermittent sprint performance and the reasons could be explained by the fact that a low caffeine dose ingestion did not affect the thermoregulatory responses compared to the placebo condition and, thus, did not attenuate its ergogenic effect on exercise in hot and humid environments.

Muscle Glycogen Content during Endurance Training under Low Energy Availability

PURPOSE

The present study investigated the effects of three consecutive days of endurance training under conditions of low energy availability (LEA) on the muscle glycogen content, muscle damage markers, endocrine regulation, and endurance capacity in male runners.

METHODS

Seven male long-distance runners (19.9 ± 1.1 yr, 175.6 ± 4.7 cm, 61.4 ± 5.3 kg, maximal oxygen uptake [V˙O2max]: 67.5 ± 4.3 mL·kg·min) completed two trials consisting of three consecutive days of endurance training under LEA (18.9 ± 1.9 kcal·kg FFM·d) or normal energy availability (NEA) (52.9 ± 5.0 kcal·kg FFM·d). The order of the two trials was randomized, with a 2-wk interval between trials. The endurance training consisted of 75 min of treadmill running at 70% of V˙O2max. Muscle glycogen content, respiratory gas variables, and blood and urine variables were measured in the morning for three consecutive days of training (days 1-3) and on the following morning after training (day 4). As an indication of endurance capacity, time to exhaustion at 19.0 ± 0.8 km·h to elicit 90% of V˙O2max was evaluated on day 4.

RESULTS

During the training period, body weight, fat-free mass, and skeletal muscle volume were significantly reduced in LEA (P = 0.02 for body weight and skeletal muscle volume, P = 0.01 for fat-free mass). Additionally, muscle glycogen content was significantly reduced in LEA (~30%, P < 0.001), with significantly lower values than those in NEA (P < 0.001). Time to exhaustion was not significantly different between the two trials (~20 min, P = 0.39).

CONCLUSIONS

Three consecutive days of endurance training under LEA decreased muscle glycogen content with lowered body weight. However, endurance capacity was not significantly impaired.

Docosahexaenoic Acid (DHA, C22:6, ω-3) Composition of Milk and Mammary Gland Tissues of Lactating Mother Rats Is Severely Affected by Lead (Pb) Exposure

Docosahexaenoic acid (DHA, C22:6, ω-3), an ω-3 polyunsaturated fatty acid (PUFA), is critical for brain growth, development, and cognitive ability. It is consumed by offspring via milk during lactation. However, the toxic heavy metal lead (Pb) readily passes into the mammary glands of mother animals and then to offspring through milk. Here, we investigated whether DHA composition of milk and mammary gland tissues is affected by Pb exposure. Mother rats were exposed to Pb via drinking water (0.1%). The fatty acid profile and levels of reduced glutathione (GSH), lipid peroxide (LPO), and pro-inflammatory TNF-α in milk and mammary tissues were measured. Levels of DHA and antioxidant GSH decreased (P < 0.05), while LPO and TNF-α levels increased (P < 0.05) both in milk and mammary tissues. Our results suggest that toxic Pb exposure can upset the level of milk DHA, which may affect brain growth and development, and hence cognitive ability in adulthood and later life.

Effect of low energy availability during three consecutive days of endurance training on iron metabolism in male long distance runners

We investigated the effect of low energy availability (LEA) during three consecutive days of endurance training on muscle glycogen content and iron metabolism. Six male long distance runners completed three consecutive days of endurance training under LEA or neutral energy availability (NEA) conditions. Energy availability was set at 20 kcal/kg fat-free mass (FFM)/day for LEA and 45 kcal/kg FFM/day for NEA. The subjects ran for 75 min at 70% of maximal oxygen uptake ( V ˙ O2max ) on days 1-3. Venous blood samples were collected following an overnight fast on days 1-4, immediately and 3 hr after exercise on day 3. The muscle glycogen content on days 1-4 was evaluated by carbon-magnetic resonance spectroscopy. In LEA condition, the body weight and muscle glycogen content on days 2-4, and the FFM on days 2 and 4 were significantly lower than those on day1 (p < .05 vs. day1), whereas no significant change was observed throughout the training period in NEA condition. On day 3, muscle glycogen content before exercise was negatively correlated with serum iron level (immediately after exercise, 3 hr after exercise), serum hepcidin level immediately after exercise, and plasma IL-6 level immediately after exercise (p < .05). Moreover, serum hepcidin level on day 4 was significantly higher in LEA condition than that in NEA condition (p < .05). In conclusion, three consecutive days of endurance training under LEA reduced the muscle glycogen content with concomitant increased serum hepcidin levels in male long distance runners.

Intake of Alpha-Linolenic Acid-Rich Perilla frutescens Leaf Powder Decreases Home Blood Pressure and Serum Oxidized Low-Density Lipoprotein in Japanese Adults

Oxidized low-density lipoprotein (Ox-LDL) is known to be highly atherogenic. Thus, decreasing the blood levels of Ox-LDL through dietary means is an important approach to reduce cardiovascular events in high-risk individuals. In this randomized placebo-controlled human interventional trial, we aimed to evaluate whether Perilla frutescens leaf powder (PLP) ameliorates Ox-LDL and home blood pressure, along with its biological antioxidant potential. Healthy Japanese volunteers aged 30-60 years (n = 60) were randomized to PLP and placebo groups. The PLP group consumed PLP dried using a microwave under reduced pressure, and the placebo group consumed pectin fiber daily for 6 months. Home blood pressure, serum biochemical parameters, and fatty acid profiles of erythrocyte plasma membranes were analyzed. Plasma Ox-LDL levels significantly decreased in the PLP group but not in the placebo group. Mean changes in the biological antioxidant potential and alpha-linolenic acid levels in the erythrocyte plasma membrane were significantly increased in the PLP group than in the placebo group. In subjects with prehypertension (systolic blood pressure [SBP] ³ 120 mmHg), the mean reduction in morning or nocturnal SBP was significantly greater in the PLP group than in the placebo group. Thus, PLP intake may be an effective intervention to prevent cardiovascular diseases.

Evaluation of fat-free mass hydration in athletes and non-athletes

PURPOSE

To evaluate the hydration of fat-free mass (FFM) in athletes and non-athletes.

METHODS

We analyzed the data of 128 healthy young adults (athletes: 61 men, 36 women; non-athletes: 19 men, 12 women) using the two-component (2C), 3C and 4C models. Under-water weighing or air-displacement plethysmography and deuterium dilution methods were used for estimating body density and total body water, respectively. The bone mineral content (BMC) was determined using whole-body scans by dual-energy X-ray absorptiometry.

RESULTS

There was no significant difference in FFM hydration between the athletes (men, 72.3 ± 1.3%; women, 71.8 ± 1.3%) and non-athletes (men, 72.1 ± 1.2%; women, 72.2% ± 1.0%) in the 3C model. The total mean FFM hydration (72.1% ± 1.3%) was similar to the corresponding value in the literature (~ 73%). The estimation error of the percentage fat by the 2C vs the 4C model was significantly and highly correlated with hydration (r = 0.96), BMC (r = - 0.70), and total body protein (r = - 0.86) in the 4C model FFM.

CONCLUSION

Although FFM hydration was similar in athletes and non-athletes, it would be underestimated or overestimated when the 2C model is used for evaluation, and the biological FFM hydration value deviates from the 73% value inter-individually. Despite that this inter-individual variation in FFM hydration is low in terms of between-individual standard deviation (1.3%), the BMC and total body protein differ greatly in athletes, and when it affects FFM hydration, it may also affect the percentage fat measurement in the 2C model. Thus, FFM hydration would not be affected by FFM, percent body fat, or the athletic status.

Effect of regional muscle damage and inflammation following eccentric exercise on electrical resistance and the body composition assessment using bioimpedance spectroscopy

We investigated the effect of muscle damage and inflammation on electrical resistance and the body composition assessment by using bioimpedance spectroscopy (BIS). Twenty-two subjects completed 30 repetitions of maximal eccentric contractions of the elbow flexors with one arm. Whole-body resistance of extracellular and intracellular components (Re and Ri, respectively) on the exercised and non-exercised sides were measured using BIS. Body composition was calculated from both sides of resistance at baseline and 96 h after exercise. Re decreased only on the exercised side at 96 h after exercise (P < 0.05). Fat-free and fat mass values estimated from resistance on the exercised side were altered by 3.1% and - 15.6%, respectively, at 96 h after exercise (P < 0.05); those estimated from the non-exercised side were unaltered. Eccentric exercise-induced muscle damage and inflammation reduce Re and induce non-negligible estimation error in the body composition assessment using BIS.

Curcumin supplementation attenuates the decrease in endothelial function following eccentric exercise

[Purpose]

Eccentric exercise induces a decrease in vascular endothelial function. Curcumin, a major component of turmeric, has potent antioxidant and anti-inflammatory properties that are associated with vascular protective effects. The present study examined the effect of acute supplementation of curcumin on eccentric exercise-induced endothelial dysfunction in healthy young men.

[Methods]

Fourteen healthy sedentary young men (range, 21–29 years) were assigned to either the curcumin (n = 6) or placebo (n = 8) group. All subjects consumed either curcumin or placebo before exercise, and eccentric exercise of the elbow flexors was performed with their nondominant arm. Before and 60 min after exercise, brachial artery flow-mediated dilation (FMD), as an indicator of endothelial function, was measured in the non-exercised arm.

[Results]

Brachial artery FMD significantly decreased following eccentric exercise (p < 0.05) in the placebo group, but acute supplementation with curcumin before exercise nullified this change. The change in FMD before and after eccentric exercise between the placebo and curcumin groups was significantly different (p < 0.05).

[Conclusion]

The present study found that acute curcumin supplementation could attenuate the decrease in endothelial function, as measured by FMD, following eccentric exercise in healthy young men.

Effective Timing of Curcumin Ingestion to Attenuate Eccentric Exercise-Induced Muscle Soreness in Men

Curcumin is known to have potent anti-inflammatory effects. We have reported that acute curcumin ingestion attenuates eccentric exercise-induced muscle damage. This study aimed to examine the effect of curcumin ingestion timing (before or after exercise) on the changes in muscle damage markers after eccentric exercise. In this randomized, single-blind, parallel design study, 24 healthy young men performed 30 maximal isokinetic (120º/s) eccentric contractions of the elbow flexors using an isokinetic dynamometer. Subjects were randomly assigned to ingest 180 mg/d of oral curcumin either 7 d before (PRE) or 4 d after exercise (POST) or 180 mg/d of oral placebo 4 d after exercise (CON). The maximal voluntary contraction (MVC) torque of the elbow flexors, elbow joint range of motion (ROM), muscle soreness, and serum creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Changes in these variables were compared over time. In the POST group, ROM were higher at 3-4 d and muscle soreness was lower at 3 d after exercise compared with the CON group (p<0.05). However, in the PRE group, there were no significant differences compared with the CON group in changes in ROM and muscle soreness. Meanwhile, there were no significant differences among the groups in terms of changes in MVC torque and serum CK activity. Our results suggest that curcumin ingestion after exercise had a more beneficial effect in attenuating muscle soreness.

Endotracheal Expandable Metallic Stent Placement in Dogs

Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. The stents were constructed of 0.45, 0.40, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface.

Treatment of Tuberculous Bronchial Stenosis with Expandable Metallic Stents

Gianturco expandable metallic stents were placed in 5 patients with dyspnea on exercise due to tuberculous bronchial stenosis. The stents were placed after dilatation with a 10-mm diameter high pressure balloon catheter. In all 5 patients, obstructive changes disappeared following the procedure, and dyspnea on exercise improved markedly. No complications related to the procedure were encountered. At follow-up during a period of up to 38 months, 2 patients showed bronchial restenosis at 11 and 17 months, respectively, after stent placement. Restenosis by granulomatous tissue was successfully treated by laser ablation. One patient showed slight one-day hemoptysis 26 months after stent placement.