Tag: maximal exercise

Comparison of the muscle oxygenation during submaximal and maximal exercise tests in patients post-coronavirus disease 2019 syndrome with pulmonary involvement

Abstract:

Introduction: Pulmonary involvement is prevalent in patients with coronavirus disease 2019 (COVID-19). Arterial hypoxemia may reduce oxygen transferred to the skeletal muscles, possibly leading to impaired exercise capacity. Oxygen uptake may vary depending on the increased oxygen demand of the muscles during submaximal and maximal exercise.

Objective: This study aimed to compare muscle oxygenation during submaximal and maximal exercise tests in patients with post-COVID-19 syndrome with pulmonary involvement.

Methods: Thirty-nine patients were included. Pulmonary function (spirometry), peripheral muscle strength (dynamometer), quadriceps femoris (QF) muscle oxygenation (Moxy® device), and submaximal exercise capacity (six-minute walk test (6-MWT)) were tested on the first day, maximal exercise capacity (cardiopulmonary exercise test (CPET)) was tested on the second day. Physical activity level was evaluated using an activity monitor worn for five consecutive days. Cardiopulmonary responses and muscle oxygenation were compared during 6-MWT and CPET.

Results: Patients’ minimum and recovery muscle oxygen saturation were significantly decreased; maximum total hemoglobin increased, heart rate, blood pressure, breathing frequency, dyspnea, fatigue, and leg fatigue at the end-of-test and recovery increased in CPET compared to 6-MWT (p < .050). Peak oxygen consumption (VO2peak) was 18.15 ± 4.75 ml/min/kg, VO2peak; percent predicted < 80% was measured in 51.28% patients. Six-MWT distance and QF muscle strength were less than 80% predicted in 58.9% and 76.9% patients, respectively.

Conclusions: In patients with post-COVID-19 syndrome with pulmonary involvement, muscle deoxygenation of QF is greater during maximal exercise than during submaximal exercise. Specifically, patients with lung impairment should be evaluated for deoxygenation and should be taken into consideration during pulmonary rehabilitation.

Source: Kavalcı Kol B, Boşnak Güçlü M, Baytok E, Yılmaz Demirci N. Comparison of the muscle oxygenation during submaximal and maximal exercise tests in patients post-coronavirus disease 2019 syndrome with pulmonary involvement. Physiother Theory Pract. 2024 Mar 12:1-14. doi: 10.1080/09593985.2024.2327534. Epub ahead of print. PMID: 38469863. https://pubmed.ncbi.nlm.nih.gov/38469863/

Patients with chronic fatigue syndrome performed worse than controls in a controlled repeated exercise study despite a normal oxidative phosphorylation capacity

Abstract:

BACKGROUND: The aim of this study was to investigate the possibility that a decreased mitochondrial ATP synthesis causes muscular and mental fatigue and plays a role in the pathophysiology of the chronic fatigue syndrome (CFS/ME).

METHODS: Female patients (n = 15) and controls (n = 15) performed a cardiopulmonary exercise test (CPET) by cycling at a continuously increased work rate till maximal exertion. The CPET was repeated 24 h later. Before the tests, blood was taken for the isolation of peripheral blood mononuclear cells (PBMC), which were processed in a special way to preserve their oxidative phosphorylation, which was tested later in the presence of ADP and phosphate in permeabilized cells with glutamate, malate and malonate plus or minus the complex I inhibitor rotenone, and succinate with rotenone plus or minus the complex II inhibitor malonate in order to measure the ATP production via Complex I and II, respectively. Plasma CK was determined as a surrogate measure of a decreased oxidative phosphorylation in muscle, since the previous finding that in a group of patients with external ophthalmoplegia the oxygen consumption by isolated muscle mitochondria correlated negatively with plasma creatine kinase, 24 h after exercise.

RESULTS: At both exercise tests the patients reached the anaerobic threshold and the maximal exercise at a much lower oxygen consumption than the controls and this worsened in the second test. This implies an increase of lactate, the product of anaerobic glycolysis, and a decrease of the mitochondrial ATP production in the patients. In the past this was also found in patients with defects in the mitochondrial oxidative phosphorylation. However the oxidative phosphorylation in PBMC was similar in CFS/ME patients and controls. The plasma creatine kinase levels before and 24 h after exercise were low in patients and controls, suggesting normality of the muscular mitochondrial oxidative phosphorylation.

CONCLUSION: The decrease in mitochondrial ATP synthesis in the CFS/ME patients is not caused by a defect in the enzyme complexes catalyzing oxidative phosphorylation, but in another factor.

TRIAL REGISTRATION: CLINICAL TRIALS REGISTRATION NUMBER: NL16031.040.07.

 

Source: Vermeulen RC, Kurk RM, Visser FC, Sluiter W, Scholte HR. Patients with chronic fatigue syndrome performed worse than controls in a controlled repeated exercise study despite a normal oxidative phosphorylation capacity. J Transl Med. 2010 Oct 11;8:93. doi: 10.1186/1479-5876-8-93. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2964609/ (Full article)

 

Nitric oxide metabolite production during exercise in chronic fatigue syndrome: a case-control study

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is a disabling illness of unknown etiology that is characterized by fatigue associated with a reduced ability to work, lasting for more than 6 months, and accompanied by a specific set of symptoms. The diagnosis remains difficult because of the absence of laboratory tests and is, therefore, made largely on the basis of the symptoms reported by the patient. The aim of this study was to analyze differences in blood nitrate levels in CFS patients and a matched control group after a physical exercise test.

METHODS: Forty-four consecutive female patients with CFS and 25 healthy women performed an exercise test using a cycle ergometer with monitoring of cardiopulmonary response. Blood samples were obtained for biochemical analyses of glucose, lactate, and nitrates at the beginning (under resting conditions) and after the maximal and supramaximal tests.

RESULTS: Plasma nitrates differed between the groups, with higher values in the CFS group (F = 6.93, p = 0.003). Nitrate concentration increased in relation to workload and reached higher values in the CFS group, the maximum difference with respect to the control group being 295% (t = 4.88, p < 0.001).

CONCLUSIONS: The main result of the present study is that nitric oxide (NO) metabolites (nitrates) showed a much higher increase after a maximal physical test in CFS patients than in a group of matched subjects. This combination (exercise plus NO response evaluation) may be useful in the assessment of CFS.

 

Source: Suárez A, Guillamó E, Roig T, Blázquez A, Alegre J, Bermúdez J, Ventura JL, García-Quintana AM, Comella A, Segura R, Javierre C. Nitric oxide metabolite production during exercise in chronic fatigue syndrome: a case-control study. J Womens Health (Larchmt). 2010 Jun;19(6):1073-7. doi: 10.1089/jwh.2008.1255. https://www.ncbi.nlm.nih.gov/pubmed/20469961

 

Prefrontal cortex oxygenation during incremental exercise in chronic fatigue syndrome

Abstract:

This study examined the effects of maximal incremental exercise on cerebral oxygenation in chronic fatigue syndrome (CFS) subjects. Furthermore, we tested the hypothesis that CFS subjects have a reduced oxygen delivery to the brain during exercise.

Six female CFS and eight control (CON) subjects (similar in height, weight, body mass index and physical activity level) performed an incremental cycle ergometer test to exhaustion, while changes in cerebral oxy-haemoglobin (HbO2), deoxy-haemoglobin (HHb), total blood volume (tHb = HbO2 + HHb) and O2 saturation [tissue oxygenation index (TOI), %)] was monitored in the left prefrontal lobe using a near-infrared spectrophotometer. Heart rate (HR) and rating of perceived exertion (RPE) were recorded at each workload throughout the test.

Predicted VO2peak in CFS (1331 +/- 377 ml) subjects was significantly (P < or = 0.05) lower than the CON group (1990 +/- 332 ml), and CFS subjects achieved volitional exhaustion significantly faster (CFS: 351 +/- 224 s; CON: 715 +/- 176 s) at a lower power output (CFS: 100 +/- 39 W; CON: 163 +/- 34 W). CFS subjects also exhibited a significantly lower maximum HR (CFS: 154 +/- 13 bpm; CON: 186 +/- 11 bpm) and consistently reported a higher RPE at the same absolute workload when compared with CON subjects. Prefrontal cortex HbO2, HHb and tHb were significantly lower at maximal exercise in CFS versus CON, as was TOI during exercise and recovery.

The CFS subjects exhibited significant exercise intolerance and reduced prefrontal oxygenation and tHb response when compared with CON subjects. These data suggest that the altered cerebral oxygenation and blood volume may contribute to the reduced exercise load in CFS, and supports the contention that CFS, in part, is mediated centrally.

 

Source: Patrick Neary J, Roberts AD, Leavins N, Harrison MF, Croll JC, Sexsmith JR. Prefrontal cortex oxygenation during incremental exercise in chronic fatigue syndrome. Clin Physiol Funct Imaging. 2008 Nov;28(6):364-72. doi: 10.1111/j.1475-097X.2008.00822.x. Epub 2008 Jul 29. https://www.ncbi.nlm.nih.gov/pubmed/18671793

 

Exercise testing in children and adolescents with chronic fatigue syndrome

Abstract:

The objective of this study was to evaluate exercise capacity in children and adolescents diagnosed with Chronic Fatigue Syndrome (CFS). We examined 20 patients (12 girls and 8 boys; mean age 14.9 +/- 3.7 years) diagnosed with CFS.

Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Fatigue was assessed using a questionnaire and a daily activity diary was used to describe activities for three days. Z-scores were calculated using age- and sex-matched reference values. Z-scores in children and adolescents with CFS were – 0.33 +/- 1.0 (p = 0.17) for peak oxygen uptake, – 1.13 +/- 1.41 (p = 0.002) for relative peak oxygen uptake [ml/kg/min] and – 0.93 +/- 1.29 (p = 0.07) for maximal work load. Both heart rate and blood pressure at peak performance were significantly reduced compared to reference values.

Fatigue levels were significantly positively associated with age and negatively with blood pressure at peak exercise (p < 0.05). In conclusion maximum exercise testing was feasible in young people with CFS. Maximal exercise capacity was only reduced in a minority of the patients and was related to current physical activity levels.

 

Source: Takken T, Henneken T, van de Putte E, Helders P, Engelbert R. Exercise testing in children and adolescents with chronic fatigue syndrome. Int J Sports Med. 2007 Jul;28(7):580-4. Epub 2007 Mar 15. https://www.ncbi.nlm.nih.gov/pubmed/17357961

 

Is physical deconditioning a perpetuating factor in chronic fatigue syndrome? A controlled study on maximal exercise performance and relations with fatigue, impairment and physical activity

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) patients often complain that physical exertion produces an increase of complaints, leading to a greater need for rest and more time spent in bed. It has been suggested that this is due to a bad physical fitness and that physical deconditioning is a perpetuating factor in CFS. Until now, studies on physical deconditioning in CFS have shown inconsistent results.

METHODS: Twenty CFS patients and 20 matched neighbourhood controls performed a maximal exercise test with incremental load. Heart rate, blood pressure, respiratory tidal volume, O2 saturation, O2 consumption, CO2 production, and blood-gas values of arterialized capillary blood were measured. Physical fitness was quantified as the difference between the actual and predicted ratios of maximal workload versus increase of heart rate. Fatigue, impairment and physical activity were assessed to study its relationship with physical fitness.

RESULTS: There were no statistically significant differences in physical fitness between CFS patients and their controls. Nine CFS patients had a better fitness than their control. A negative relationship between physical fitness and fatigue was found in both groups. For CFS patients a negative correlation between fitness and impairment and a positive correlation between fitness and physical activity was found as well. Finally, it was found that more CFS patients than controls did not achieve a physiological limitation at maximal exercise.

CONCLUSIONS: Physical deconditioning does not seem a perpetuating factor in CFS.

 

Source: Bazelmans E, Bleijenberg G, Van Der Meer JW, Folgering H. Is physical deconditioning a perpetuating factor in chronic fatigue syndrome? A controlled study on maximal exercise performance and relations with fatigue, impairment and physical activity. Psychol Med. 2001 Jan;31(1):107-14. http://www.ncbi.nlm.nih.gov/pubmed/11200949