High-intensity intermittent inspiratory and abdominal muscle combined training in respiratory, swallowing and systemic muscles of healthy adults.

BACKGROUND: Low-intensity continuous inspiratory muscle training improves its strength. The abdominal muscles are the main expiratory muscles, and their training may improve expiratory muscle strength. Respiratory muscle strength regulates coughing effectiveness, which is critical for pneumonia management. In older people, risk factors for the development of pneumonia were respiratory muscle weakness and swallowing impairment. Currently, the impact of high-intensity intermittent inspiratory and abdominal muscle combined training on the respiratory, swallowing, and systemic muscles is unclear. OBJECTIVE: We aimed to explore the effects of high-intensity inspiratory muscle training combined with or without abdominal muscle training on respiratory muscle strength as well as the strength, mass, and performance of swallowing and systemic muscles. METHODS: Twenty-eight healthy adults were divided into two groups. Participants performed high-intensity intermittent inspiratory muscle single or its combination with abdominal muscle training for 4 weeks. Respiratory muscle strength, swallowing muscle strength and mass, systemic muscle strength, mass and performance were measured at baseline, Week 2 and Week 4. RESULTS: Both groups showed greater maximal respiratory pressures at Week 2 and Week 4 than baseline. Both groups showed improved tongue pressure and geniohyoid muscle thickness at Week 4. In addition, the combined training group improved body trunk muscle mass, handgrip strength and five-time chair stand test, whereas the single training group did not. CONCLUSION: This study revealed that high-intensity inspiratory muscle training improved inspiratory muscle strength and swallowing muscle strength and mass. Moreover, inspiratory and abdominal muscle combined training showed an additional benefit of improving systemic muscle strength, mass and performance. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000046724; https://upload.umin.ac.jp/cgi-open-bin/ctr/index.cgi?ctrno=UMIN000046724.

Factors associated with quality of life in patients receiving lung transplantation: a cross-sectional study.

BACKGROUND: With improved prognosis after lung transplantation (LTx), improving health-related quality of life (HRQL) in patients who have undergone LTx is a key goal. Although HRQL is improved significantly after transplantation, it is poorer than that in ordinary healthy people. However, the factors associated with poor HRQL remain unclear. This cross-sectional study aimed to identify the factors associated with poor HRQL in patients who have undergone LTx. METHODS: Between December 2018 and May 2022, 80 patients who had undergone LTx completed St. George's Respiratory Questionnaire (SGRQ) as a disease-specific quality of life measure, the Short Form-12 (SF-12) as a generic quality of life measure, and modified Medical Research Council (mMRC) scale of dyspnea. The groups were assigned according to the median SGRQ-total score and the Japanese population standard for SF-12, and those with good HRQL were compared with those with poor HRQL. Independent factors were evaluated using multivariate analysis. RESULTS: With regard to the SGRQ, there were significant differences in the forced expiratory volume in 1 s (FEV1) (P = 0.041), use of bronchodilators (P = 0.026), 6-min walk distance (6MWD) (P < 0.001), and Mmrc (P < 0.001) between better and poorer HRQL. For the SF-12 physical component summary score (PCS), age (P = 0.017), sex (P = 0.011), FEV1 (P < 0.001), forced vital capacity (FVC) (P < 0.001), diagnosis (P = 0.011), handgrip force (P = 0.003), 6MWD (P < 0.001), and Mmrc (P < 0.001) varied. Multivariate analyses revealed that Mmrc was the only independent factor in the SGRQ (P < 0.001, odds ratio [OR] = 6.65, 95% confidence interval [CI]: 2.49-17.74) and SF-12 PCS (P = 0.001, OR = 0.185, 95% CI: 0.07-0.52). There were significant correlations between the SGRQ-Total score and SF-12 PCS (correlation coefficient = -0.612, P < 0.001). CONCLUSIONS: Dyspnea may be an independent factor of poor disease-specific and generic HRQL in LTx patients. The management of dyspnea may improve the HRQL in patients who have undergone LTx.

A Systematic Review of Reported Methods of Stimulating Swallowing Function and their Classification.

Recent advances in dysphagia treatment have given us many methods of stimulating swallowing function, but no attempt has been made to systematically classify them all. In this review, we provide an exhaustive description of all the techniques and stimulatory substances that stimulate swallowing that have so far been reported in the scientific literature, irrespective of their level of evidence, and we have tried to classify them with the objective of encouraging the future development of research in this direction. The Preferred Reporting Items for Systematic Reviews and Meta-analysis were followed for retrieval of relevant research. A total of 237 records were screened for this literature review. One record was excluded for being published in a language other than English, and 59 articles were excluded for having no original data. Of the 177 records that were assessed for eligibility in this review, 31 were excluded for reasons related to other inclusion and exclusion criteria. Finally, 146 records were classified. We found stimuli related to swallowing published in the literature could be divided into physical and chemical stimuli. Each stimulus had both peripheral and central stimuli when we assessed the main site of action. Physical stimuli included electric, magnetic and thermal stimulations and acupuncture. Chemical stimuli included spices activating transient receptor potential channels, several categories of medications, taste and flavor, and olfactory stimulants. Medications modifying substance P and the dopaminergic system are thought to be peripheral and central stimuli, respectively. This classification may pave the way to discover means to improve swallowing.

Appendicular Skeletal Muscle Mass Correlates with Patient-Reported Outcomes and Physical Performance in Patients with Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF), an incurable lung disease of unknown cause, often presents with losses of skeletal muscle mass. IPF requires comprehensive care, but it has not been investigated which skeletal muscle mass index reflects holistic management factors: pulmonary function, patient-reported outcomes (PROs), and physical performance. We compared three representative indices of skeletal muscle mass with holistic management factors in IPF patients. Twenty-seven mild to severe IPF patients (21 male) with the mean age of 76.1 ± 5.9 years were enrolled. The three indices were appendicular skeletal muscle mass index (ASMI), cross-sectional area of pectoralis major (PMCSA), and cross-sectional area of erector spinae muscles (ESMCSA). ASMI is considered as a gold standard for sarcopenia assessment, while PMCSA and ESMCSA are frequently used in IPF. As PROs, we assessed breathlessness with the modified Medical Research Council dyspnea scale (mMRC), symptoms with the chronic obstructive pulmonary disease assessment test (CAT), and health-related quality of life with St. George's Respiratory Questionnaire (SGRQ). For physical performance, peripheral muscle strength and 6-min walk distance (6MWD) were investigated. In this cross-sectional study, ASMI showed the greatest number of significantly correlated indices, such as pulmonary function, peripheral muscle strength, 6MWD, mMRC, and SGRQ. PMCSA showed the next greatest number of correlations, with peripheral muscle strength, 6MWD, and mMRC, whereas ESMCSA showed no significant correlations with any index. Thus, ASMI correlated with both PROs and physical performance, and PMCSA correlated mainly with physical performance. In conclusion, assessing ASMI is helpful for the comprehensive care of patients with IPF.

Molecular and Neural Mechanism of Dysphagia Due to Cancer.

Cancer is one of the most common causes of death worldwide. Along with the advances in diagnostic technology achieved through industry-academia partnerships, the survival rate of cancer patients has improved dramatically through treatments that include surgery, radiation therapy, and pharmacotherapy. This has increased the population of cancer "survivors" and made cancer survivorship an important part of life for patients. The senses of taste and smell during swallowing and cachexia play important roles in dysphagia associated with nutritional disorders in cancer patients. Cancerous lesions in the brain can cause dysphagia. Taste and smell disorders that contribute to swallowing can worsen or develop because of pharmacotherapy or radiation therapy; metabolic or central nervous system damage due to cachexia, sarcopenia, or inflammation can also cause dysphagia. As the causes of eating disorders in cancer patients are complex and involve multiple factors, cancer patients require a multifaceted and long-term approach by the medical care team.

Role of O-C2 angle in the development of dysphagia in patients with halo-vest fixation.

BACKGROUND: Dysphagia is one of the most serious complications in patients treated with a halo-vest brace. However, the cause of dysphagia development by halo-vest fixation is not yet clear. We therefore investigated the incidence of dysphagia and cervical alignment as well as clinical data from medical charts in patients treated with a halo-vest brace. METHODS: We retrospectively reviewed clinical data from the medical charts of 49 patients who had undergone halo-vest fixation. Occipito (O)-C2 angle, C2-C6 angle, and pharyngeal inlet angle were assessed by lateral plain X-rays of the cervical spine. The impacts of these parameters on incidence and severity of dysphagia were analyzed. RESULTS: Thirteen patients (32%) suffered from dysphagia during halo-vest fixation, and age and length of intensive care unit (ICU) stay were greater in the dysphagia group (p = 0.044 and 0.013, respectively) than in those who did not develop dysphagia. O-C2 angle was smaller in the dysphagia group (p = 0.016). After multivariate logistic analysis, body mass index, ICU stay, and O-C2 angle remained as independent risk factors related to incidence of dysphagia. Spearman rank correlation showed a negative correlation between ICU stay and Food Intake Level Scale (FILS) (p = 0.026), and a positive correlation between O-C2 angle and FILS (p = 0.008). CONCLUSION: This study suggested that O-C2 angle is related to both incidence and severity of dysphagia due to halo-vest fixation.

Improvement of Pulmonary Function after Comprehensive Obesity Rehabilitation Program in Obese Patients.

Obesity is a major risk factor of cardiovascular, osteoarthritis, metabolic and pulmonary disorders, and exercise is an efficient method for treating obesity. However, obese patients often complain of dyspnea on exertion, which makes it difficult to continue exercise program. Obesity is also known to have an adverse effect on pulmonary function. The purpose of this study was to examine the effects of a comprehensive obesity rehabilitation (COR) program on pulmonary function in Japanese patients with morbid obesity. We enrolled 29 Japanese obese patients (14 males and 15 females) with BMI > 29 and an average age of 42.2 ± 11.7 years, who underwent the COR program for 1-3 months. Our COR program included a calorie-restricted diet, nutritional counseling, exercise training, and health education. We focused on the changes in pulmonary function, anticipating that changes in ventilation volume may contribute to improving exercise tolerance. After the intervention, all the subjects had lost weight, with a mean value of 12.0 kg (P < 0.001). We found that the lung volume compartment was significantly increased after our COR program, and that there is a strong positive correlation between a change in expiratory reserve volume and the weight loss (r = 0.74, P < 0.01). Through the COR program, body fat mass was significantly reduced, while the skeletal muscle mass remained more or less unchanged, which is advantageous for improvement in exercise tolerance. In conclusion, our COR program is helpful to improve the pulmonary function of patients with obesity.

Chronic inflammation, lymphangiogenesis, and effect of an anti-VEGFR therapy in a mouse model and in human patients with aspiration pneumonia.

Chronic inflammation induces lymphangiogenesis and blood vessel remodelling. Since aged pneumonia patients often have repeated episodes of aspiration pneumonia, the pathogenesis may involve chronic inflammation. For lymphangiogenesis, VEGFR-3 and its ligand VEGF-C are key factors. No previous studies have examined chronic inflammation or vascular changes in aspiration pneumonia or its mouse models. In lung inflammation, little is known about the effect of blocking VEGFR-3 on lung lymphangiogenesis and, moreover, its effect on the disease condition. This study aimed to establish a mouse model of aspiration pneumonia, examine the presence of chronic inflammation and vascular changes in the model and in patients, and evaluate the effect of inhibiting VEGFR-3 on the lymphangiogenesis and disease condition in this model. To induce aspiration pneumonia, we repeated inoculation of pepsin at low pH and LPS into mice for 21-28 days, durations in which bronchioalveolar lavage and plasma leakage in the lung suggested the presence of exaggerated inflammation. Conventional and immunohistochemical analysis of tracheal whole mounts suggested the presence of chronic inflammation, lymphangiogenesis, and blood vessel remodelling in the model. Quantitative RT-PCR of the trachea and lung suggested the involvement of lymphangiogenic factor VEGF-C, VEGFR-3, and pro-inflammatory cytokines. In the lung, the aspiration model showed the presence of chronic inflammation and exaggerated lymphangiogenesis. Treatment with the VEGFR inhibitor axitinib or the VEGFR-3 specific inhibitor SAR131675 impaired lymphangiogenesis in the lung and improved oxygen saturation in the aspiration model. Since the lung is the main site of aspiration pneumonia, the changes were intensive in the lung and mild in the trachea. Human lung samples also showed the presence of chronic inflammation and exaggerated lymphangiogenesis, suggesting the relevance of the model to the disease. These results suggest lymphatics in the lung as a new target of analysis and therapy in aspiration pneumonia.

The wish to die among palliative home care clients in Ontario, Canada: A cross-sectional study.

BACKGROUND: In the pursuit to provide the highest quality of person centered palliative care, client preferences, needs, and wishes surrounding end of life should be used to inform the plan of care. During a clinical assessment for care services, clients may voluntarily express a 'wish to die' either directly to the clinician or it may be indirectly reported second-hand to the clinician through an informal caregiver or family member. This is the first study using data gathered from the interRAI Palliative Care Assessment instrument (interRAI PC) to examine socio-demographic, clinical, and psycho-social factors of palliative home care clients with the voluntary expression of a 'wish to die now'. Factors associated with the risk for depression within this group were also identified. Awareness and understanding of clients who express the 'wish to die' is needed to better tailor a person-centered approach to end-of-life care. METHODS: This cross-sectional study included assessment records gathered from 4,840 palliative home care clients collected as part of pilot implementation of the interRAI PC assessment instrument in Ontario, Canada from 2006 through 2011. RESULTS: During the clinical assessment, 308 palliative home care clients (6.7%) had voluntarily expressed a 'wish to die now'. Independent factors emerging from multivariate logistic regression analyses predicting the expression of a 'wish to die' included not being married/widowed, a shorter estimated prognosis, depressive symptoms, functional impairment, too much sleep (excessive amount), feeling completion regarding financial/legal matters, and struggling with the meaning of life. Among persons who expressed a 'wish to die now', those who exhibited depressive symptoms (23.8%, n = 64) were also more likely to exhibit cognitive impairment, have decline in cognition in the last 90 days, exhibit weight loss, have informal caregivers exhibiting distress, 'not have a consistent positive outlook on life' and report 'struggling with the meaning of life'. CONCLUSION: When clients voluntary express a wish to die clinicians should take notice and initiate follow-up to better understand the context of this meaning for the individual. Clients who expressed a 'wish to die' did not all experience pain, depression, and psychological distress suggesting an individualized approach to care management be taken.

[Perioperative Management and Minimally Invasive Pulmonary Resection-early Stage Rehabilitation, Postoperative Early Ambulation].

In chest surgery, minimal invasiveness is an important topic. Video-assisted thoracic surgery and a less radical resection may be effective for decreasing postoperative complications or postoperative mortality rates. Respiratory rehabilitation is useful for preventing postoperative complications, and it is used pre- and postoperatively for patients with lung cancer and chronic obstructive pulmonary disease (COPD) in most hospitals. Although it is well adapted to patients with a lower forced expiratory volume in 1 second, higher stages of COPD, severe emphysematous changes on computed tomography, and performance status ≥2, there are no definitive criteria for rehabilitation. Before initiating respiratory rehabilitation for patients, it is important to evaluate their risk factors, such as sputum production, articular disturbances, or activities. There are many kinds of rehabilitation, but preoperative respiratory rehabilitation is especially effective in inoperable cases to improve respiratory function, to change their status to operable, and to decrease periods of chest-tube drainage or hospital admission. It should be used for minimally invasive chest surgery from now on.

Comprehensive Geriatric Assessment in the era of telemedicine.

The aging global population poses significant medical and social challenges, necessitating efforts to promote healthy aging. Comprehensive Geriatric Assessment (CGA) is a multidimensional diagnostic approach for older adults that aims to improve overall health. Remote CGA, facilitated by technological advancements, offers convenience and other potential advantages. It enables early disease detection, monitors chronic disease progression, delivers personalized care, and optimizes healthcare resources for better health outcomes in older individuals. However, remote CGA also has limitations, including technological requirements, data security, and the need for comprehensive evaluation and simplicity. Collaborative efforts are essential to developing a digital home-based CGA platform that addresses accessibility issues and tailors the assessment process to meet the needs of older adults. Continuous optimization of remote CGA can become a pivotal tool for advancing geriatric care and ensuring the well-being of the aging population. Geriatr Gerontol Int 2024; 24: 67-73.

Differences in kinetic factors affecting gait speed between lesion sides in patients with stroke.

The differences in kinetic mechanisms of decreased gait speed across brain lesion sides have not been elucidated, including the arrangement of motor modules reflected by kinetic interjoint coordination. The purpose of this study was to elucidate the differences in the kinetic factors of slow gait speed in patients with stroke on the lesion sides. A three-dimensional motion analysis system was employed to assess joint moment in the lower limb and representative gait parameters in 32 patients with right hemisphere brain damage (RHD) and 38 patients with left hemisphere brain damage (LHD) following stroke as well as 20 healthy controls. Motor module composition and timing were determined using principal component analysis based on the three joint moments in the lower limb in the stance phase, which were the variances accounted for principal components (PCs) and the peak timing in the time series of PCs. A stepwise multiple linear regression analysis was performed to identify the most significant joint moment and PC-associated parameter in explaining gait speed. A negligible difference was observed in age, weight, height, and gait speed among patients with RHD and LHD and controls. The following factors contributed to gait speed: in patients with RHD, larger ankle plantarflexion moment on the paretic (p = 0.001) and nonparetic (p = 0.002) sides and ankle dorsiflexion moment on the nonparetic side (p = 0.004); in patients with LHD, larger ankle plantarflexion moment (p < 0.001) and delayed peak timing of the first PC (p = 0.012) on the paretic side as well as ankle dorsiflexion moment on the nonparetic side (p < 0.001); in the controls, delayed peak timing of the first PC (p = 0.002) on the right side and larger ankle dorsiflexion moment (p = 0.001) as well as larger hip flexion moment on the left side (p = 0.023). The findings suggest that the kinetic mechanisms of gait speed may differ among patients with RHD following patients with stroke with LHD, and controls.

Effects of body postures on respiratory muscle force and coughing in healthy people.

The respiratory muscle force determines the intensity of cough force. A greater cough force for cleaning the airways is essential for preventing and managing pneumonia. Body posture can affect the onset of aspiration pneumonia. However, the effects of body posture on the respiratory muscle and cough forces remain unclear. Thus, we aimed to explore the influence of the four body postures on respiratory muscle force, cough pressure, subjective ease of coughing, and pulmonary function in healthy individuals. Twenty healthy individuals were included in this study. Body postures were 0-degree supine, 30- and 60-degree semi-recumbent, and 90-degree sitting. The maximal inspiratory and expiratory pressures, maximal cough pressure, subjective ease of coughing, and pulmonary function, including peak expiratory flow, were evaluated. We set the measured values in the supine posture to 100% and showed the relative values. The 60-degree posture showed stronger inspiratory (125.1 ± 3.9%, mean ± standard error [SE]) and expiratory (116.4 ± 3.0%) muscle force, cough pressure, more subjective ease of coughing, and greater peak expiratory flow (113.4 ± 3.0%) than the supine posture. The sitting posture also showed greater inspiratory muscle force and peak expiratory flow than the supine posture. The correlation coefficient for the 60-degree posture showed that the maximal inspiratory pressure was moderately correlated with the maximal expiratory pressure (r = 0.512), cough pressure (r = 0.495), and peak expiratory flow (r = 0.558). The above findings suggest the advantage of keeping a 60-degree posture and avoiding the supine posture to generate a greater cough force in the prevention and management of pneumonia.

Gait classification of knee osteoarthritis patients using shoe-embedded internal measurement units sensor.

BACKGROUND: Knee osteoarthritis negatively affects the gait of patients, especially that of elderly people. However, the assessment of wearable sensors in knee osteoarthritis patients has been under-researched. During clinical assessments, patients may change their gait patterns under the placebo effect, whereas wearable sensors can be used in any environment. METHODS: Sixty patients with knee osteoarthritis and 20 control subjects were included in the study. Wearing shoes with an IMU sensor embedded in the insoles, the participants were required to walk along a walkway. The sensor data were collected during the gait. To discriminate between healthy and knee osteoarthritis patients and to classify different subgroups of knee osteoarthritis patients (patients scheduled for surgery vs. patients not scheduled for surgery; bilateral knee osteoarthritis diagnosis vs. unilateral knee osteoarthritis diagnosis), we used a machine learning approach called the support vector machine. A total of 88 features were extracted and used for classification. FINDINGS: The patients vs. healthy participants were classified with 71% accuracy, 85% sensitivity, and 56% specificity. The "patients scheduled for surgery" vs. "patients not scheduled for surgery" were classified with 83% accuracy, 83% sensitivity, and 81% specificity. The bilateral knee osteoarthritis diagnosis vs. unilateral knee osteoarthritis diagnosis was classified with 81% accuracy, 75% sensitivity, and 79% specificity. INTERPRETATION: Gait analysis using wearable sensors and machine learning can discriminate between healthy and knee osteoarthritis patients and classify different subgroups with reasonable accuracy, sensitivity, and specificity. The proposed approach requires no complex gait factors and is not limited to controlled laboratory settings.

Impact of Controlling Nutritional Status Score on Mortality in Elderly Patients with Idiopathic Pulmonary Fibrosis.

Background: There are only a few reports on the nutritional status and mortality of patients with idiopathic pulmonary fibrosis (IPF). As such, this study aims to investigate the relationship between controlling nutritional status (CONUT) and the mortality of elderly patients with IPF. Methods: A total of 170 IPF patients aged ≥65 years old who visited the rehabilitation department of our hospital between July 2014 and July 2021 (mean age: 75.7 ± 6.3 years, sex (male/female): 138/32, %FVC: 78.3 ± 18.3%) were retrospectively analyzed. The Kaplan-Meier method and log-rank test were applied. Furthermore, using a Cox proportional hazards model with multivariate analysis, we analyzed the relationship between all-cause mortality and baseline characteristics including CONUT. Results: Based on the CONUT score, the normal group included 101 cases, the mild group included 58 cases, the moderate group included 11 cases, and the severe group had 0 cases. There were 49 cases of all-cause mortality events, suggesting that the mortality of the moderate group was significantly poorer than that of the normal and mild groups (p < 0.05). Furthermore, multivariate analysis identified GAP stage (HR: 5.972, 95%CI: 2.901~12.291, p < 0.0001), mMRC scale (HR: 0.615, 95%CI: 0.389~0.971, p = 0.009), and CONUT (HR: 2.012, 95%CI: 1.192~3.395, p = 0.037) as factors significantly influencing mortality. Conclusions: Severe malnutrition was not observed in elderly patients with IPF. Moderate malnutrition was associated with a significantly higher risk of all-cause mortality, suggesting that CONUT is an important indicator for predicting mortality.

Correlation between pulmonary function and brain volume in healthy elderly subjects.

INTRODUCTION: Cigarette smoking decreases brain regional gray matter volume and is related to chronic obstructive lung disease (COPD). COPD leads to decreased pulmonary function, which is represented by forced expiratory volume in one second percentage (FEV1.0 %); however, it is unclear if decreased pulmonary function is directly related to brain gray matter volume decline. Because there is a link between COPD and cognitive decline, revealing a direct relationship between pulmonary function and brain structure is important to better understand how pulmonary function affects brain structure and cognitive function. Therefore, the purpose of this study was to analyze whether there were significant correlations between FEV1.0 % and brain regional gray and white matter volumes using brain magnetic resonance (MR) image data from 109 community-dwelling healthy elderly individuals. METHODS: Brain MR images were processed with voxel-based morphometry using a custom template by applying diffeomorphic anatomical registration using the exponentiated lie algebra procedure. RESULTS: We found a significant positive correlation between the regional white matter volume of the cerebellum and FEV1.0 % after adjusting for age, sex, and intracranial volume. CONCLUSION: Our results suggest that elderly individuals who have a lower FEV1.0 % have decreased regional white matter volume in the cerebellum. Therefore, preventing decreased pulmonary function is important for cerebellar white matter volume in the healthy elderly population.

[Rehabilitation for Amyotrophic Lateral Sclerosis and ALS clinic].

The dysfunctions of amyotrophic lateral sclerosis (ALS) are highly variable. Rehabilitation medicine for movement disorders differs in accordance with the degree of severity. Exercise therapy should be performed while the disease is mild, with compensatory training increasing as the severity increases. Exercise therapy with a Hybrid Assistive Limb®(HAL®) is generally thought to preserve lower extremity function compared to those without HAL®. The mechanism may be effective on disused muscle fibers. ALS clinic may improve the prognosis of ALS patients.

Importance of Skeletal Muscle and Interdisciplinary Team Approach in Managing Pneumonia in Older People.

Pneumonia is the most frequent lower respiratory tract disease and a major cause of morbidity and mortality globally [...].

L-menthol administration facilitates breathing comfort during exhaustive endurance running and improves running capacity in well-trained runners: A randomized crossover study.

ABSTRACTThis study aimed to clarify the contribution of L-menthol administration to endurande exercise capacity. Thirteen male runners (age, 35.8 ± 7.8 years; peak oxygen uptake, 62.7 ± 6.8 mL kg-1 min-1) ran on treadmills at fixed intensities of their anaerobic thresholds to exhaustion. All participants underwent three trials-water ingestion (W-IG), L-menthol mouth rinsing (M-MR), and L-menthol ingestion (M-IG)- in a random order every 5 min while running. Breathing comfort (BC) was measured immediately after fluid intake. Dyspnea threshold against external inspiratory resistance was examined before and after the running test. The running time with M-IG (1683.9 ± 520.3 s) was longer than that with W-IG (1410.2 ± 465.9 s, effect size [ES] = 0.55). BC with M-IG (2.00 ± 0.74) was higher than that with W-IG (0.42 ± 0.79) at exhaustion (ES > 2.00). The dyspnea threshold after running decreased to 19.2 ± 7.6 cm H2O L-1 s-1 with W-IG, whereas that with M-MR (26.2 ± 6.5 cm H2O L-1 s-1) and M-IG (29.2 ± 2.8 cm H2O L-1 s-1) remained high (p for interaction < 0.001). M-IG facilitated BC during running, improved endurance capacity, and prevented decreases in the dyspnea threshold against external inspiratory resistance after exhaustive running.HighlightsL-menthol ingestion facilitated breathing comfort during high intensity endurance running and improved exhaustive endurance running capacity.Even after exhaustion, L-menthol solution relieved dyspnea sensitivity against external inspiratory resistance.L-menthol ingestion might help athletes improve their endurance running capacity.