Prevalence of depressive symptoms and related risk factors in Japanese patients with pulmonary nontuberculous mycobacteriosis.

The objective of this study was to administer commonly used tools, the Center for Epidemiological Studies Depression Scale (CES-D) and the Hospital Anxiety and Depression Scale - Depression subscale (HADS-D), to screen for depressive symptoms in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). In addition, we sought to identify whether differences existed in the prevalence of depressive symptoms as assessed by CES-D and HADS-D, and by various predictors of depression. The presence of depressive symptoms in 95 patients with NTM-PD was assessed using the CES-D and HADS-D. Data regarding age, body mass index, pulmonary function, dyspnea, cough, and exercise capacity were obtained to examine their independent contribution as predictors of depressive symptoms. The prevalence of depressive symptoms was 37.9% based on CES-D and 26.3% based on HADS-D. The prevalence of depressive symptoms based on CES-D and HADS-D revealed significant differences between the two instruments. Analysis suggested that the presence of cough is a significant predictor of depressive symptoms as assessed by both CES-D and HADS-D. Countermeasures are necessary because some patients with NTM-PD disease have depressive symptoms. It is possible that assessment of the prevalence of depressive symptoms differs in accordance with the screening tool used.

Incremental Shuttle Walk Distance as an Indicator for Functional Exercise Capacity of Pre-Surgical Patients with Nontuberculous Mycobacterial Lung Disease.

The incidence of nontuberculous mycobacterial lung disease (NTMLD) is increasing worldwide, the number of lung surgeries is increasing accordingly. The disease is progressive and is characterized by exertional intolerance, respiratory dysfunctions, and impaired health-related quality of life (HRQOL). Treatment comprises multidrug antibiotic treatment combined with lung resection. The incremental shuttle walk distance (ISWD) is a standard tool for assessing the patients' tolerance to lung resection. The exertional tolerance, physical functions and HRQOL among pre-surgical patients with NTMLD are clinically important, but not fully studied yet from the viewpoint of physiotherapy. The purpose of this study was to explore the clinical significance of ISWD for assessing the exercise capacity of pre-surgical patients with NTMLD. For peripheral muscle evaluation, the strength of the quadriceps femoris muscle was measured. HRQOL was evaluated using scores of the St. George's Respiratory Questionnaire (SGRQ). Thirty-three patients (mean age 54.9 ± 13 years) were enrolled. The mean ISWD was 505 ± 134 m, shorter than the reference values (ISWD %predicted: 96 ± 27%). Regression analysis showed significant associations between ISWD and percent-predicted vital capacity (r = 0.38, p = 0.03) and percent quadriceps force/body weight (r = 0.54, p = 0.001). HRQOL assessed by SGRQ scores was correlated with ISWD (r < -0.4, p < 0.05). Multiple regression analysis showed that ISWD was significantly associated with leg muscle strength and with HRQOL. In conclusion, ISWD is useful to evaluate the exercise capacity among pre-surgical patients with NTMLD.

Smoking aggravates the impaired pulmonary function of officially acknowledged female victims of air pollution of 40 years ago.

Air pollution due to industrial waste and tobacco smoke is detrimental to pulmonary function. However, the combined effects of air pollution and smoking on pulmonary function have not been investigated. We examined the combined effect of air pollution of 40 years ago and concurrent smoking on the pulmonary function of officially acknowledged female victims in Japan, because females are more susceptible to the adverse effects of both irritants than males. The subjects comprised 655 female victims living in one of two areas with air pollution of 40 years ago and 572 females living in an area without air pollution. All victims have been prescribed standard respiratory medications. Pulmonary function was measured in 2000 for air-pollution groups (130 smokers and 525 non-smokers; mean age, 68.4 years) and during the period of 2004 to 2013 for non-air-pollution groups (113 smokers and 459 non-smokers; mean age, 69.0 years). The smokers included both current smokers and ex-smokers. The victims with a history of smoking had significantly lower forced expiratory volume in 1 second (FEV1 % predicted) (mean, 74%) and significantly lower FEV1/forced vital capacity (FVC) (mean, 70%) than the other groups (P<0.001). Thus, smoking aggravates the pulmonary function in officially acknowledged female victims, despite the improved air pollution and the continuous medical care provided by the government. In conclusion, exposure to air pollution of 40 years ago and cigarette smoking are associated with reduced pulmonary function. These results highlight the importance of measures aimed at smoking cessation and limiting air pollution.

A 6-month follow-up after constraint-induced movement therapy with and without transfer package for patients with hemiparesis after stroke: a pilot quasi-randomized controlled trial.

OBJECTIVE: To investigate the long-term effects of the 'transfer package' in constraint-induced movement therapy, which is an optional protocol to facilitate actual use of the trained affected arm in activities of daily living. DESIGN: A pilot quasi-randomized controlled trial with a blinded single assessor with six-month follow-up. SETTING: Hospitalized care at university hospital. SUBJECTS: Twenty-one post-stroke patients were quasi-randomized to either a group with transfer package during constraint-induced movement therapy or a control group (without transfer package). INTERVENTIONS: The transfer package group received 4.5 hours of intensive task training and 0.5 hours of transfer package whereas the control group received 5.0 hours of intensive task training per day during 10 consecutive weekdays. MAIN MEASURES: Arm function was measured with Fugl-Meyer Assessment and Amount of Use score of Motor Activity Log. RESULTS: Twenty-three patients were quasi-randomized, but data from two patients were missing from the long-term follow-up. Both groups showed increase in arm function postintervention. However, at six months' follow-up only the transfer package group showed consistent increase in arm function (with transfer package group versus control group; Fugl-Meyer Assessment, mean (± SD) from 48.6 ± 7.8 (preintervention) to 55.7 ± 4.5 (postintervention) and 59.0 ± 3.6 (six months postintervention) versus from 49.1 ± 5.5 to 52.8 ± 6.0 and 53.3 ± 4.9, P= 0.003; Amount of Use scale of Motor Activity Log, mean from 1.3 ± 0.55 (preintervention) to 2.12 ± 0.55 (postintervention) and 2.79 ± 0.98 (six months postintervention) versus from 1.18 ± 0.70 to 1.61 ± 0.54 and 1.65 ± 0.68, P= 0.002). CONCLUSIONS: Our results confirmed the long-term effects of the transfer package in constraint-induced movement therapy.

Air pollution irreversibly impairs lung function: a twenty-year follow-up of officially acknowledged victims in Japan.

Lung function is one of the strongest determinants of cardiopulmonary health and longevity. Long-term exposure to air pollution has been associated with decreased lung function. We undertook a retrospective study to compare the long-term consequences of air pollution in two areas of Japan: Mizushima, Okayama Prefecture and Kitakyushu, Fukuoka Prefecture. Industrialization began in Mizushima in the 1940s, whereas it began in Kitakyushu in the early 1900s. In Kitakyushu, levels of nitrogen dioxide have been higher compared to the Mizushima area. The subjects comprised 623 officially acknowledged victims of pollution-related illness (489 from Mizushima and 134 from Kitakyushu). All subjects were lifetime non-smokers and aged 65 years or older at the time of their last medical examination in 2009. Demographic data including diagnosed lung diseases and lung function at the time of certification assessment performed between 1973 and 1988 were obtained. The subjects from Kitakyushu were significantly younger (47.1 vs. 51.0 years, p < 0.001) and a higher percentage had asthma (91.2 vs. 36.8%, p < 0.001) compared to those from Mizushima. Furthermore, all measures of lung function were significantly lower in Kitakyushu group at the time of the certification assessment (p < 0.001) and at the follow-up (p < 0.001). However, no significant differences were observed in the annual mean decline in lung function between the two groups, despite the overall decrease in air pollution. In conclusion, the normal lung function is not restored even after improvement of air pollution. It is essential for every city to prevent air pollution.

Physical Function and Health-Related Quality of Life after Surgery for Nontuberculous Mycobacterial Pulmonary Disease: A Prospective Cohort Study.

PURPOSE: To investigate the exercise capacity and health-related quality of life (HRQOL) of surgical patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) preoperatively versus 6 months postoperatively. METHODS: This prospective observational study included patients with NTM-PD and was conducted at a single center. The intervention was surgical resection plus perioperative and post-discharge physical therapy. The physical function was assessed preoperatively and 6 months postoperatively using the 6-minute walk test (6MWT). HRQOL was assessed preoperatively and 6 months postoperatively using the Short-Form 36 (SF-36) health survey questionnaire and St. George's Respiratory Questionnaire. The postoperative HRQOL was compared between patients with and without preoperative clinical symptoms. RESULTS: In total, 35 patients were analyzed. The preoperatively symptomatic group had significantly lower preoperative HRQOL than the preoperatively asymptomatic group (p <0.05). Compared with preoperatively, there were significant improvements at 6 months postoperatively in the 6MWT (p <0.01) and HRQOL, mainly in the SF-36 mental component summary (p <0.01). The SF-36 mental component summary in the preoperatively symptomatic group was very significantly improved from preoperatively to 6 months postoperatively (p <0.05). CONCLUSION: The combination of surgical treatment and physical therapy for NTM-PD contributes to improvements in physical function and HRQOL.

Clinical significance and safety of combined treatment with chemotherapy and pulmonary rehabilitation regarding health-related quality of life and physical function in nontuberculous mycobacterial pulmonary disease.

BACKGROUND: In the treatment of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD), pulmonary rehabilitation (PR) has been recommended as a non-pharmacological therapy. However, no study has validated the combination of chemotherapy and PR in this context. This study investigated the effect of chemotherapy and supervised PR on health-related quality of life (HRQoL) and physical function in NTM-PD patients. METHODS: This prospective cohort study included patients diagnosed with NTM-PD who had a planned hospitalization of at least 3 weeks for chemotherapy and PR. HRQoL (Leicester Cough Questionnaire [LCQ] and chronic obstructive pulmonary disease assessment test [CAT]), physical function (incremental shuttle walk distance [ISWD], quadriceps force), and C-reactive protein levels were assessed before and after treatment, and the corresponding data were analyzed in conjunction with clinical data. The adverse events of PR were also investigated. RESULTS: Forty-two patients who met the study criteria were included in the analysis. After treatment, all LCQ item scores, total CAT score and sub-item scores related to respiratory symptoms, ISWD, quadriceps force, and C-reactive protein levels were found to have improved significantly. In the chronic cough with excessive sputum production (CCS) group, the proportions of responders who showed improvements in LCQ and CAT scores and ISWD greater than the corresponding minimal clinically important difference were significantly greater than those in the non-CCS group. No PR-related adverse events were reported. CONCLUSIONS: Combined treatment with chemotherapy and PR may improve HRQoL and physical function, and supervised PR can be provided safely.

Decreased incremental shuttle walk test distance characterized by fibrocavitary lesions in non-tuberculous mycobacterial pulmonary disease.

BACKGROUND: Patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD) have impaired exercise capacity, but the underlying factors are unknown. We investigated the characteristics of patients with NTM-PD and impaired exercise capacity. METHODS: In total, 149 patients with NTM-PD participated in this study. Patients completed the incremental shuttle walk test (ISWT) to assess exercise capacity. Peripheral muscle strength and pulmonary function were also assessed. Radiological findings were classified into three phenotypes: non-cavitary nodular bronchiectatic (NC-NB) form, cavitary nodular bronchiectatic form, and fibrocavitary (FC) form. RESULTS: The median ISWT distance (ISWD) and %ISWD were 450 meters and 88%. Participants were classified into three groups according to %ISWD, with %ISWD <60% as the severely decreased group, 60%-80% as the moderately decreased group, and >80% as the normal or mildly decreased group. In a comparison of %ISWD among phenotypes, FC form had significantly lower %ISWD than those with NC-NB form. In the severely decreased group, peripheral muscle strength and pulmonary function were significantly lower than the other two groups. From a radiological standpoint, significantly more patients had FC form in the group with severely decreased %ISWD. CONCLUSIONS: Decreased ISWD is characterized by a deterioration in physical function and the presence of FC lesions in NTM-PD.

Influence of chronic sputum symptoms on quality of life in patients with nontuberculous mycobacterial pulmonary disease: A cross-sectional study.

BACKGROUND: The effect of chronic sputum (CS) symptoms on health-related quality of life (HRQOL) in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) has not been studied. The aim of this study was to clarify the differences in the clinical characteristics of NTM-PD patients with and without CS and to investigate the effect of CS on HRQOL. METHODS: This cross-sectional study included patients with NTM-PD who were prescribed pulmonary rehabilitation at the Fukujuji Hospital from March 2016 to June 2019. HRQOL was evaluated using the MOS 36-Item Short-Form Health Survey (SF-36). RESULTS: Of the 99 subjects studied, 71 had CS (CS+) (71.7%), and 28 (28.3%) did not have CS (CS-). Patients in the CS + group had a lower body mass index, forced vital capacity percent predicted, and forced expiratory volume in 1 s percent predicted. Regarding the radiological evaluation, the proportion of patients with the fibrocavitary form and the radiological score were significantly higher in the CS + group. The mental component summary (MCS) score of the SF-36 were significantly lower in the CS + group. Multiple regression analysis showed that the presence of CS was independently associated with a lower MCS score of the SF-36. CONCLUSIONS: NTM-PD patients with CS had more severe disease, with reduced pulmonary function and severe radiological findings. CS was shown to independently affect HRQOL, especially mental status.

Is the Leicester Cough Questionnaire useful for nontuberculous mycobacterial lung disease?

BACKGROUND: Although the incidence of nontuberculous mycobacterial lung disease (NTM-LD) is increasing worldwide, there is no established standard of care leading to eradication. Therefore, research on health-related quality of life (HRQOL) is important for patients with NTM-LD. HRQOL is commonly evaluated using the St. George's Respiratory Questionnaire (SGRQ), developed for chronic obstructive pulmonary disease (COPD). However, NTM-LD differs from COPD in that few patients complain of dyspnea or wheezing, and cough and sputum are their main symptoms. The Leicester Cough Questionnaire (LCQ) is an HRQOL questionnaire dedicated to cough, but few studies have used it for NTM-LD. This study evaluated HRQOL in patients with NTM-LD using the SGRQ and LCQ and clarified the usefulness of the LCQ. METHODS: Information on age, height, weight, lung function, percent ideal body weight, laboratory data, radiological scores, exercise capacity, SGRQ, and LCQ were collected from the medical records of 81 patients. Correlations between SGRQ and LCQ domains were assessed using Spearman's rank correlation coefficients. Multivariate analysis was performed with SGRQ and LCQ total scores. RESULTS: Statistically significant correlations were observed between all domains, and the correlation between the total scores was -0.67 (p < 0.01). Multivariate analysis with total scores as the dependent variable showed that the explanatory variables were lung function (p < 0.05) and radiological score (p < 0.05) in the SGRQ, and radiological score (p < 0.05) and C-reactive protein level (p < 0.05) in the LCQ. CONCLUSION: The LCQ, which evaluates an inflammatory response involved in the diagnosis of NTM-LD, may be useful to assess HRQOL in patients with NTM-LD.

Effects of pain on depression, sleep, exercise tolerance, and quality of life in patients with nontuberculous mycobacterial pulmonary disease.

ABSTRACT: The experience and causes of pain in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) have not been clarified.This study aimed to determine the prevalence and severity of bodily pain (BP) in patients with NTM-PD. We also investigated the clinical indicators that contribute to pain.We used a retrospective cross-sectional study design. The participants were 114 NTM-PD patients (109 women) with a mean age of 65 years. The prevalence and severity of pain were measured using 2 items from the 36-Item Short Form Survey version 2 (SF-36), and the BP score was calculated. Functional limitation due to dyspnea was quantified using the Modified Medical Research Council Dyspnea Scale (mMRC), depression was assessed using the Center for Epidemiological Studies Depression Scale (CES-D), sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI); health-related quality of life was assessed using the Leicester Cough Questionnaire (LCQ), and exercise tolerance was measured using the Incremental Shuttle Walk Test (ISWT).Pain was reported by 70.2% of the patients (n = 80), and of these, 35.7% (n = 25) reported moderate to very severe pain. NTM-PD patients with high levels of pain had significantly higher scores on the mMRC, CES-D, and PSQI scores, and significantly lower performance on the ISWT and LCQ. Multiple regression analysis identified ISWT, CES-D, and PSQI as independent factors that affected BP scores.Our findings suggest that pain significantly impacts daily life associated with reduced exercise tolerance, the presence of depressive symptoms, and poor sleep quality in patients with NTM-PD.

Effects of Systematic Intervention for Chronic Obstructive Pulmonary Disease on Follow-up and Smoking Cessation Rates and Changes of the Pulmonary Function: A 7-year Longitudinal Study in a Japanese Rural City.

Objective The early detection and treatment of chronic obstructive pulmonary disease (COPD) requires comprehensive follow-up over a long period. The aim of this study was to determine the effects of a comprehensive long-term intervention system developed by the COPD Task Force for a rural city in Japan during a 7-year period. Methods This prospective, community-based longitudinal study encompassed 2006-2013 in Matsuura City, Japan. Primary and secondary screenings were performed for the early diagnosis and treatment of COPD. Individuals diagnosed with COPD were managed by the COPD Task Force's comprehensive early intervention system. The outcomes of interest were the rate of continuous follow-up after the diagnosis of COPD, the smoking cessation rate, and changes in the pulmonary function during a 7-year period. Subjects The study included 8,878 residents of 50-89 years of age who resided in Matsuura in 2006. Results In total, 140 participants received definitive diagnoses of COPD in 2006. After 7 years of intervention, 34 patients withdrew; 78 (74%) patients continued with treatment in our intervention system. The rate of smoking cessation was significantly increased in the intervention group (from 30% to 68%; p<0.01) over the 7-year period. The change in forced expiratory volume in 1 second (FEV1) was -23.2 mL/year. Conclusion Our systematic longitudinal intervention system during a 7-year period led to high rates of follow-up and smoking cessation. Furthermore, our system may be able to prevent the decline of FEV1 in COPD patients. This intervention system may be effective in rural cities with few respiratory physicians.

Effect of a chronic obstructive pulmonary disease (COPD) intervention on COPD awareness in a regional city in Japan.

OBJECTIVE: The purpose of this study was to examine the effect of an intervention for chronic obstructive pulmonary disease (COPD) on COPD awareness in a regional city in Japan. METHODS: Self-administered questionnaires were completed by the residents of the city of Matsuura, Japan. Residents (≥50 years) of the mainland in Matsuura were included in a COPD intervention project (mainland group), while residents of the islands district received no intervention due to geographical issues (island group). The rates of COPD awareness and accuracy of responses to the questions about COPD were compared between the two groups. MATERIALS: The study included 5,891 residents 40 to 74 years of age of Matsuura in 2013. The mainland group comprised 4,419 subjects, and the island group 1,472 included subjects. RESULTS: The overall response rate to the questionnaire was 24.6%, with similar response rates between the two groups. The rate of COPD awareness in the mainland group was 24.5%, which was significantly higher than that observed in the island group (11.8%) (p<0.01). The rate of awareness tended to decrease in association with increasing age. Among 276 responders who stated they were aware of COPD, the accuracy rate for responses to the questions about COPD was not significantly different between the groups. CONCLUSION: In the present study, there was a difference in COPD awareness between the two groups, suggesting that COPD interventions may increase awareness of the disease. However, the level of knowledge regarding COPD remained low and modifications to the intervention are required to improve awareness of the condition, especially among elderly subjects.

Value of systematic intervention for chronic obstructive pulmonary disease in a regional Japanese city based on case detection rate and medical cost.

OBJECTIVE: We established a COPD taskforce for early detection, diagnosis, treatment, and intervention. We implemented a pilot intervention with a prospective and longitudinal design in a regional city. This study evaluates the usefulness of the COPD taskforce and intervention based on COPD case detection rate and per capita medical costs. METHOD: We distributed a questionnaire to all 8,878 inhabitants aged 50-89 years, resident in Matsuura, Nagasaki Prefecture in 2006. Potentially COPD-positive persons received a pulmonary function test and diagnosis. We implemented ongoing detection, examination, education, and treatment interventions, performed follow-up examinations or respiratory lessons yearly, and supported the health maintenance of each patient. We compared COPD medical costs in Matsuura and in the rest of Nagasaki Prefecture using data from 2004 to 2013 recorded by the association of Nagasaki National Health Insurance Organization, assessing 10-year means and annual change. RESULTS: As of 2014, 256 people have received a definitive diagnosis of COPD; representing 31% of the estimated total number of COPD patients. Of the cases detected, 87.5% were mild or moderate in severity. COPD medical costs per patient in Matsuura were significantly lower than the rest of Nagasaki Prefecture, as was rate of increase in cost over time. CONCLUSION: The COPD program in Matsuura enabled early detection and treatment of COPD patients and helped to lower the associated burden of medical costs. The success of this program suggests that a similar program could reduce the economic and human costs of COPD morbidity throughout Japan.

Tobacco use among designated air pollution victims and its association with lung function and respiratory symptoms: a retrospective cross-sectional study.

OBJECTIVES: We sought to elucidate the long-term association of tobacco use and respiratory health in designated pollution victims with and without obstructive pulmonary defects. DESIGN: A retrospective cross-sectional study. SETTING: The register of pollution victims in Kurashiki, Japan. PARTICIPANTS: 730 individuals over 65 years of age previously diagnosed with pollution-related respiratory disease. Patients were classified into four groups according to their smoking status and whether they had obstructive pulmonary disease. We then compared the prevalence of respiratory symptoms and lung function over time between groups. PRIMARY OUTCOME MEASURES: Spirometry was performed and a respiratory health questionnaire completed in the same season each year for up to 30 years. RESULTS: Rates of smoking and respiratory disease were high in our sample. Although respiratory function in non-smoking patients did not completely recover, the annual rate of change in lung function was within the normal range (p<0.01). However, smokers had worse lung function and were more likely to report more severe pulmonary symptoms (p<0.01). CONCLUSIONS: Patients' respiratory function did not fully recover despite improved air quality. Our results suggest that, in the context of exposure to air pollution, tobacco use causes additional loss of lung function and exacerbates respiratory symptoms.

Detection of airflow limitation using the 11-Q and pulmonary function tests.

OBJECTIVE: To investigate whether chronic obstructive pulmonary disease (COPD) screening that combines screening with questionnaires and pulmonary function testing is a useful method for the early detection of COPD. METHODS: A total of 3,367 subjects over 50 years of age underwent COPD screening. Two thousand five hundred and seventy-two of these subjects underwent "Ningen Dock" (a Japanese-English term for annual health checkup) examinations, regularly-scheduled checkups or screenings in outpatient clinics. Of these subjects, 795 lived in one city and one town in Nagasaki Prefecture and exhibited a score of at least 5 points on the Eleven-item pre-interview questionnaire (11-Q). The prevalence of airflow limitation in each type of examination was calculated for each gender, and the odds ratios of airflow limitation with each type of examination were obtained using the subjects who underwent "Ningen Dock" examinations as the reference group. RESULTS: The COPD prevalence was 6.5% in the "Ningen Dock" group (7.9% men, 1.8% women), 5.8% in the regularly-scheduled checkup group (7.4% men, 4.1% women), 9.8% in the screening in outpatient clinics group (12.1% men, 7.2% women) and 22.3% in the COPD screening group (31.1% men, 8.1% women), with the COPD screening group showing the highest prevalence. The odds ratios of the COPD prevalence confirmed that COPD screening is more effective for identifying airflow limitation than other types of examinations. CONCLUSION: Conducting COPD screening with questionnaires and pulmonary function testing among the general population is a useful examination method for the early detection and treatment of COPD.

Vastus lateralis oxygenation during prolonged cycling in healthy males.

This study examined the relationship between acute cardiorespiratory and muscle oxygenation and blood volume changes during prolonged exercise. Eight healthy male volunteers (mean maximum oxygen uptake VO(2max) = 41.6 +/- 2.4 mL/kg/min) performed 60 min submaximal cycling at 50% VO(2max). Oxygen uptake VO(2) was measured by indirect spirometry, cardiac output (CO) was estimated using a Portapre, and right vastus lateralis oxyhemoglobin/ myoglobin (oxyHb/Mb), deoxyhemoglobin/myoglobin (deoxyHb/Mb), and total hemoglobin/myoglobin (total Hb/Mb) were recorded using near-infrared spectroscopy (NIRS). After 40 min of exercise, there was a significant increase in VO(2) due to a significantly higher arteriovenous oxygen difference ((a - v)O(2diff). After 30 min of exercise CO remained unchanged, but there was a significant decrease in stroke volume and a proportionate increase in heart rate, thus indicating the occurrence of cardiovascular drift. During the first few minutes of exercise, there was a decline in oxyHb/Mb and total Hb/Mb, whereas deoxyHb/Mb remained unchanged. Thereafter, oxyHb/Mb and total Hb/Mb increased systematically until the termination of exercise while deoxyHb/Mb declined. After 40 min of exercise, these changes were significantly different from the baseline values. There were no significant correlations between the changes in the NIRS variables and systemic VO(2) or mixed (a - v)O(2)diff during exercise. These results suggest that factors other than localized changes in muscle oxygenation and blood volume account for the increased VO(2) during prolonged submaximal exercise.