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1.
Tidsskr Nor Laegeforen ; 143(11)2023 08 15.
Artigo em Inglês, Norueguês | MEDLINE | ID: mdl-37589367

RESUMO

Breast cancer is the most common cancer among women in Norway. Nine out of ten will become long-term survivors. Being cancer-free does not necessarily mean feeling healthy, and many experience troublesome late effects, such as fatigue, pain and fear of recurrence. General practitioners represent the most important medical support for the majority of these women. This clinical review article summarises up-to-date knowledge about late effects after breast cancer treatment. Non-pharmacological interventions can have a positive effect on many of the most common late effects.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Neoplasias da Mama/terapia , Progressão da Doença , Emoções , Fadiga/etiologia , Fadiga/terapia , Medo
2.
Integr Cancer Ther ; 22: 15347354231164401, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37358259

RESUMO

INTRODUCTION: Cognitive complaints are common late effects in patients with cancer, and no standard treatment exists. Recent studies with several patient populations have indicated that there is potential to improve working memory (WM) via web-based WM training. However, the feasibility of including web-based WM training as part of inpatient cancer rehabilitation, in combination with unprompted home-based training, has not been studied. The aim of this study was to assess the feasibility of including web-based WM training (using Cogmed QM) during inpatient rehabilitation and its subsequent unprompted completion in a home-based setting. METHODS: Patients with cancer who self-reported cognitive complaints were instructed to complete 25 Cogmed QM sessions during their 3-week inpatient multidisciplinary cancer rehabilitation and subsequently at home after discharge from rehabilitation. The feasibility was determined by assessing the study recruitment, adherence to the WM training, improvements in training tasks (compliance measure) and patient experiences by individual interviews. RESULTS: Twenty-nine (27 women) of 32 eligible patients (89.6%) started WM training, 1 declined participation and 2 patients withdrew before WM training started. Twenty-six of 29 (89.6%) participants adhered to the intervention during rehabilitation, while 19 of 29 (65.5%) also adhered to the subsequent unprompted home-based intervention. All participants who completed the Cogmed QM sessions demonstrated improvements in the training tasks, as defined by the Cogmed Improvement Index (MD = 24.05, SD = 9.38, range 2-44, P < .011). Interview data suggested that practical limitations, including a lack of time, technical difficulties, difficulties finding a suitable disturbance-free environment and low motivation were barriers to completing the training at home. CONCLUSION: The findings show that it is feasible to include web-based WM training during inpatient multidisciplinary rehabilitation for adult patients with cancer with cognitive complaints. However, patient adherence to unprompted web-based WM training after discharge from rehabilitation was not optimal. Thus, future studies should consider the barriers to adherence and the need for supervision and social support to reinforce home-based training.


Assuntos
Memória de Curto Prazo , Neoplasias , Adulto , Humanos , Feminino , Pacientes Internados , Estudos de Viabilidade , Treino Cognitivo , Internet
3.
Nat Sci Sleep ; 13: 435-446, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790676

RESUMO

PURPOSE: Poor sleep quality in chronic obstructive pulmonary disease (COPD) is a result of oxygen desaturation secondary to compromised lung function. Nitrate supplementation with dietary beetroot juice is known to elevate plasma nitrate and to increase the efficiency of oxygen utilization in non-COPD individuals; whether it is of therapeutic benefit for sleep quality in COPD has not been reported. PATIENTS AND METHODS: In a counterbalanced within-subjects design involving 15 COPD patients as subjects, the subjects consumed either beetroot juice containing nitrate (BJ; ∼6.2 mmol NO3 -) or placebo (NO3 - -depleted juice) immediately before a night of polysomnographic monitoring. Nitrate was measured in plasma collected immediately after waking. RESULTS: While BJ consumption had no effect on the amount of time spent in any sleep stages, wake-to-N2 transitions and direct wake-to-rapid eye movement sleep (REMS) transitions, hallmarks of disordered sleep, were less frequent on the BJ night than on the placebo night. In the last two hours of the BJ night, percent time in REMS increased and delta power during deep (N3) non-REMS decreased, relative to the placebo night. Collectively, the reduced frequency of atypical transitions and the normalization of non-REMS/REMS dynamics after BJ are indicative of an improvement of sleep quality. BJ also resulted in sustained elevation of peripheral oxygen saturation (SpO2), during episodes of wake after sleep onset. Plasma nitrate was elevated nearly tenfold on the morning after BJ relative to placebo. CONCLUSION: BJ has a normalizing effect on disordered sleep in COPD, which may be related to improved oxygen delivery. CLINICAL TRIAL REGISTRATION: The activities of the Regional Committees for Medical and Health Research Ethics (REC) are founded on the Norwegian law on research ethics and medical research. This study was approved by NTNU/REK midt, Det medisinske fakultet, Postboks 8905, 7491 Trondheim (REK midt 2016/1360).

5.
Scand J Public Health ; 49(2): 188-196, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32883170

RESUMO

AIMS: Our aim was to investigate labor-force participation, working hours, job changes, and education over 9 years among persons who have survived more than 10 years after cancer, and compare it to controls. METHODS: Register data on 2629 persons who survived cancer were stratified by gender and compared to data on 5258 matched controls. Persons who survived cancer were aged 30-50 when diagnosed with cancer and had a work contract prior to diagnosis. Descriptive analysis and t-tests were performed. RESULTS: The proportion of female persons who survived cancer in the labor force was reduced from 100% to 83.9% during follow-up, demonstrating a significant difference compared to controls for each year measured. The proportion of male persons who survived cancer dropped from 100% to 84.8%, but was only significantly different compared to controls in 2 years. The proportion of female persons who had survived cancer who worked full-time was lower in all years compared to both controls and male persons who survived cancer; in turn, male persons who had survived cancer worked full-time less than male controls. The proportion of female persons who had survived cancer who worked less than 20 hours per week increased compared to controls. The frequency of change of employer was higher among female persons who survived cancer compared to controls for some years, but no significant differences between male persons who survived cancer and controls were found. Female persons who survived cancer were in education more often than male persons who survived cancer. CONCLUSIONS: Persons who survived cancer experienced reduced labor-force participation and working hours 9 years after diagnosis, and the reduction was more pronounced for women than for men. Working patterns were also different between genders and between persons who survived cancer and controls.


Assuntos
Sobreviventes de Câncer/estatística & dados numéricos , Emprego/estatística & dados numéricos , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Noruega , Sistema de Registros , Fatores Sexuais
6.
J Public Health Res ; 9(4): 1739, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33381469

RESUMO

Background. Many cancer survivors experience late effects of cancer treatment and therefore struggle to return to work. Norway provides rehabilitation programs to increase labor force participation for cancer survivors after treatment. However, the extent to which such programs affect labor force participation has not been appropriately assessed. This study aims to investigate i) labor force participation, sick leave and disability rates among cancer survivors up to 10 years after being diagnosed with cancer and identify comorbidities contributing to long-term sick leave or disability pensioning; ii) how type of cancer, treatment modalities, employment sectors and financial- and sociodemographic factors may influence labor force participation; iii) how participation in rehabilitation programs among cancer survivor affect the longterm labor force participation, the number of rehospitalizations and incidence of comorbidities. Design and methods. Information from four medical, welfare and occupational registries in Norway will be linked to information from 163,279 cancer cases (15.68 years old) registered in the Norwegian Cancer Registry from 2004 to 2016. The registries provide detailed information on disease characteristics, comorbidities, medical and surgical treatments, occupation, national insurance benefits and demographics over a 10-year period following a diagnosis of cancer. Expected impact of the study for Public Health. The study will provide important information on how treatment, rehabilitation and sociodemographic factors influence labor force participation among cancer survivors. Greater understanding of work-related risk factors and the influence of rehabilitation on work-participation may encourage informed decisions among cancer patients, healthcare and work professionals and service planners.

7.
J Appl Physiol (1985) ; 129(6): 1324-1329, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33031018

RESUMO

Ingestion of dietary nitrate ([Formula: see text]) is associated with improved exercise tolerance and reduced oxygen (O2) cost of exercise, ascribed to enhanced mitochondrial efficiency, muscle contractile function, or other factors. Nitrate ingestion has also been found to attenuate the reduction in arterial oxygen saturation ([Formula: see text]) during apnea and to prolong apneic duration. The spleen serves as a dynamic blood pool expelling erythrocytes into the circulation during apnea, and [Formula: see text] and nitric oxide donors may induce vasoactive effects in the mesenteric and splanchnic circulation. Our aim was to investigate the effect of ingestion of concentrated organic [Formula: see text]-rich beetroot juice (BR) on spleen volume and spleen contraction during apnea, and the resulting hemoglobin (Hb) concentration. Eight volunteers performed two apneas of submaximal and maximal duration during prone rest ∼2.5 h after ingesting 70 mL of BR (∼5 mmol [Formula: see text]) or placebo (PL; ∼0.003 mmol [Formula: see text]), on separate days in weighted order. Heart rate and [Formula: see text] were monitored continuously and spleen diameters were measured every minute for triaxial volume calculation. Capillary Hb samples were collected at baseline and after the maximal apnea. Baseline spleen volume was reduced by 66 mL after BR ingestion (22.9%; P = 0.026) and Hb was elevated (+3.0%; P = 0.015). During apneas, spleen contraction and Hb increase were similar between BR and PL conditions (NS). The study shows that dietary [Formula: see text]reduces spleen volume at rest, resulting in increased Hb. This spleen-induced Hb elevation following [Formula: see text] ingestions represents a novel mechanism that could enhance performance in conditions involving exercise, apnea, and hypoxia.NEW & NOTEWORTHY This is the first study to examine changes of spleen volume and circulating Hb following dietary [Formula: see text] supplementation. After dietary [Formula: see text] ingestion, the spleen volume at rest was reduced and Hb was elevated. The spleen contains a dynamic red blood cell reservoir, which can be mobilized and facilitate oxygen transport during various types of physiological stress. This study has revealed an additional, previously unexplored mechanism possibly contributing to the ergogenic effects of dietary [Formula: see text].


Assuntos
Beta vulgaris , Nitratos , Suplementos Nutricionais , Ingestão de Alimentos , Humanos , Consumo de Oxigênio , Baço
8.
High Alt Med Biol ; 21(1): 84-91, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32182148

RESUMO

The human spleen can contract and transiently boost the blood with stored erythrocytes. We measured spleen volume and contraction during apneas in two groups, each containing 12 Caucasian participants (each 3 women): one group planning to summit Mt. Everest (8848 m; "Climbers") and another trekking to Everest Base Camp (5300 m; "Trekkers"). Tests were done in Kathmandu (1370 m) 1-3 days after arrival, before the Climb/Trek. Age, height, weight, vital capacity, resting heart rate, and arterial oxygen saturation were similar between groups (not significant). After 15 minutes of sitting rest, all participants performed a 1-minute apnea and, after 2 minutes of rest, 1 maximal duration apnea was performed. Six of the climbers did a third apnea and hemoglobin concentration (Hb) was measured. Three axial spleen diameters were measured by ultrasonic imaging before and after the apneas for spleen volume calculation. Mean (standard deviation) baseline spleen volume was larger in Climbers [367 (181) mL] than in Trekkers [228 (70) mL; p = 0.022]. Spleen contraction occurred during apneas in both groups, with about twice the magnitude in Climbers. Three apneas in six of the Climbers resulted in a spleen volume reduction from 348 (145) to 202 (91) mL (p = 0.005) and an Hb elevation from 147.9 (13.1) to 153.3 (11.3) g/L (p = 0.024). Maximal apneic duration was longer in Climbers [88 (23) seconds vs. 67 (18) seconds in Trekkers; p = 0.023]. We concluded that a large spleen characterizes Climbers, suggesting that spleen function may be important for high-altitude climbing performance.


Assuntos
Apneia , Montanhismo , Altitude , Apneia/diagnóstico por imagem , Eritrócitos , Feminino , Humanos , Oximetria , Baço/diagnóstico por imagem , Ultrassonografia
9.
Sci Rep ; 9(1): 19392, 2019 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-31852958

RESUMO

Obstructive sleep apnea (OSA) worsens outcomes in Chronic Obstructive Pulmonary Disease (COPD), and reduced sleep quality is common in these patients. Thus, objective sleep monitoring is needed, but polysomnography (PSG) is cumbersome and costly. The WatchPAT determines sleep by a pre-programmed algorithm and has demonstrated moderate agreement with PSG in detecting sleep stages in normal subjects and in OSA patients. Here, we validated WatchPAT against PSG in COPD patients, hypothesizing agreement in line with previous OSA studies. 16 COPD patients (7 men, mean age 61 years), underwent simultaneous overnight recordings with PSG and WatchPAT. Accuracy in wake and sleep staging, and concordance regarding total sleep time (TST), sleep efficiency (SE), and apnea hypopnea index (AHI) was calculated. Compared to the best fit PSG score, WatchPAT obtained 93% sensitivity (WatchPAT = sleep when PSG = sleep), 52% specificity (WatchPAT = wake when PSG = wake), 86% positive and 71% negative predictive value, Cohen's Kappa (κ) = 0.496. Overall agreement between WatchPat and PSG in detecting all sleep stages was 63%, κ = 0.418. The mean(standard deviation) differences in TST, SE and AHI was 25(61) minutes (p = 0.119), 5(15) % (p = 0.166), and 1(5) (p = 0.536), respectively. We conclude that in COPD-patients, WatchPAT detects sleep stages in moderate to fair agreement with PSG, and AHI correlates well.


Assuntos
Artérias/fisiologia , Manometria , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Apneia Obstrutiva do Sono/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/fisiopatologia , Polissonografia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Sono/fisiologia , Apneia Obstrutiva do Sono/fisiopatologia
10.
Undersea Hyperb Med ; 45(1): 55-63, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29571233

RESUMO

A number of competitive water sports are performed while breath-holding (apnea). Such performances put large demands on the anaerobic system, but the study of lactate accumulation in apneic sports is limited. We therefore aimed to determine and compare the net lactate accumulation (NLA) during competition events in six disciplines of competitive freediving (FD) and three disciplines of synchronized swimming (SSW). The FD disciplines were: static apnea (STA; n = 14); dynamic apnea (DYN; n = 19); dynamic apnea no fins (DNF; n = 16); constant weight (CWT; n = 12); constant weight no fins (CNF; n = 8); free immersion (FIM; n =10). The SSW disciplines were solo (n = 21), duet (n = 31) and team (n = 34). Capillary blood lactate concentration was measured before and three minutes after competition performances, and apneic duration and performance variables were recorded. In all nine disciplines NLA was observed. The highest mean (SD) NLA (mmol·L-1) was found in CNF at 6.3 (2.2), followed by CWT at 5.9 (2.3) and SSW solo at 5 (1.9). STA showed the lowest NLA 0.7 (0.7) mmol·L-1 compared to all other disciplines (P ⟨ 0.001). The NLA recorded shows that sports involving apnea involve high levels of anaerobic activity. The highest NLA was related to both work done by large muscle groups and long apneic periods, suggesting that NLA is influenced by both the type of work and apnea duration, with lower NLA in SSW due to shorter apneic episodes with intermittent breathing.


Assuntos
Suspensão da Respiração , Mergulho/fisiologia , Ácido Láctico/sangue , Natação/fisiologia , Adulto , Desempenho Atlético/fisiologia , Feminino , Humanos , Masculino , Fatores de Tempo
11.
High Alt Med Biol ; 19(1): 21-27, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29211505

RESUMO

Patrician, Alexander, Harald Engan, David Lundsten, Ludger Grote, Helena Vigetun-Haughey, and Erika Schagatay. The effect of dietary nitrate on nocturnal sleep-disordered breathing and arterial oxygen desaturation at high altitude. High Alt Med Biol 19:21-27, 2018.-Sleep-disordered breathing and fluctuations in arterial oxygen saturation (SaO2) are common during sleep among lowlanders ascending to high altitude. Dietary nitrate (NO3-) supplementation has been shown to lower the O2 consumption in various conditions. Our objective was to investigate whether dietary NO3- could reduce sleep-disordered breathing and SaO2 desaturation during sleep at altitude. Cardiorespiratory responses during sleep were measured in 10 healthy lowlanders at 330 m and then again in the Himalayas at 3700-4900 m. Each subject received two 70 mL shots of either beetroot juice (BR; ∼5.0 mmol NO3- per shot) or placebo (PL: ∼0.003 mmol NO3- per shot) in a single-blinded, weighted order over two consecutive nights at altitude. At 2.5-4.5 hours into sleep at altitude, BR increased the SaO2 desaturation drop (4.2 [0.1]% with PL vs. 5.3 [0.4]% with BR; p = 0.024) and decreased the SaO2 desaturation duration (14.1 [0.9] seconds with PL to 11.1 [0.9] seconds with BR; p = 0.0.041). There was a reduction in breaths with flow limitation (p = 0.025), but no changes in Apnea-Hypopnea Index (AHI), mean and minimum SaO2. The study suggests BR supplementation does not improve AHI or oxygenation, but may increase fluctuations in arterial O2 saturation during sleep at altitude in native lowlanders.


Assuntos
Sucos de Frutas e Vegetais , Nitratos/farmacologia , Oxigênio/sangue , Síndromes da Apneia do Sono/sangue , Altitude , Beta vulgaris , Dieta , Feminino , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Raízes de Plantas , Índice de Gravidade de Doença , Método Simples-Cego , Adulto Jovem
12.
Disabil Rehabil ; 38(24): 2406-12, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-26800715

RESUMO

PURPOSE: The aim of the present paper was to study preferences for web based self-administered questionnaires (web SAQs) vs. paper-based self-administered questionnaires (paper SAQs) and to evaluate the feasibility of using web SAQs in patients referred to cardiac, lung, occupational and cancer rehabilitation programs. METHODS: The patients were approached by mail and given the choice to answer the compulsory SAQs either on paper or on a web-based platform. RESULTS: Hundred and twenty seven out of 183 eligible patients (69.3%) were willing to participate and 126 completed the study. Web SAQs were preferred by 77.7%, and these patients were significantly younger, more often cohabiting and tended to have higher level of education than paper SAQ users. Mean number of data missing per patient was less among the web SAQ users than the paper SAQ users (0.55 vs. 2.15, p < 0.001). Costs related to human resources were estimated to be 60% lower with web SAQs compared to paper SAQs. CONCLUSIONS: Web SAQs were well accepted among the patients scheduled for rehabilitation, led to less missing data and considerable cost savings related to human resources. Patients referred to rehabilitation should be offered the choice to complete self-administered questionnaires on internet platforms when internet access is common and available. Implications for Rehabilitation The high acceptability of web-based self-administered questionnaires among rehabilitation patients suggests that internet platforms are suitable tools to collect patient information for rehabilitation units. Web-based modes of patient data collection demonstrate low number of missing data and can therefore improve the quality of data collection from rehabilitation patients. Use of web-based questionnaires considerably reduces administrative costs of data collection in rehabilitation settings compared to traditional pen and paper methods.


Assuntos
Indicadores Básicos de Saúde , Reabilitação/normas , Inquéritos e Questionários , Adulto , Autoavaliação Diagnóstica , Estudos de Viabilidade , Feminino , Humanos , Internet , Masculino , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde , Preferência do Paciente , Reabilitação/métodos , Inquéritos e Questionários/normas
13.
Nitric Oxide ; 50: 58-64, 2015 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-26325324

RESUMO

INTRODUCTION: Dietary nitrate (NO3-) supplementation serves as an exogenous source of nitrite (NO2-) and nitric oxide (NO) through the NO3- - NO2- - NO pathway, and may improve vascular functions during normoxia. The effects of NO3- supplementation in healthy lowlanders during hypobaric hypoxia are unknown. PURPOSE: Determine the effect of acute oral NO3-supplementation via beetroot juice (BJ) on endothelial function (flow mediated dilation; FMD) in lowlanders at 3700 m. METHODS: FMD was measured using ultrasound and Doppler in the brachial artery of 11 healthy subjects (4 females, age 25 ± 5 yrs; height 1.8 ± 0.1 m, weight 72 ± 10 kg) sojourning to high altitude. In a randomized, double-blinded crossover study design, FMD was measured 3 h after drinking BJ (5.0 mmol NO3-) and placebo (PL; 0.003 mmol NO3-) supplementation at 3700 m, with a 24-h wash out period between tests. FMD was also measured without any BJ supplementation pre-trek at 1370 m, after 5 days at 4200 m and upon return to 1370 m after 4 weeks of altitude exposure (above 2500 m). The altitude exposure was interrupted by a decent to lower altitude where subjects spent two nights at 1370 m before returning to altitude again. RESULTS: Ten subjects completed the NO3- supplementation. FMD (mean ± SD) pre-trek value was 6.53 ± 2.32% at 1370 m. At 3700 m FMD was reduced to 3.84 ± 1.31% (p < 0.01) after PL supplementation but was normalized after receiving BJ (5.77 ± 1.14% (p = 1.00). Eight of the subjects completed the interrupted 4-week altitude stay, and their FMD was lower at 4200 m (FMD 3.04 ± 2.22%) and at post-altitude exposure to 1370 m (FMD 3.91 ± 2.58%) compared to pre-trek FMD at 1370 m. CONCLUSION: Acute dietary NO3-supplementation may abolish altitude-induced reduction in endothelial function, and can serve as a dietary strategy to ensure peripheral vascular function in lowland subjects entering high altitude environments.

15.
High Alt Med Biol ; 15(1): 52-7, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24673535

RESUMO

Release of stored red blood cells resulting from spleen contraction improves human performance in various hypoxic situations. This study determined spleen volume resulting from two contraction-evoking stimuli: breath holding and exercise before and after altitude acclimatization during a Mount Everest ascent (8848 m). Eight climbers performed the following protocol before and after the climb: 5 min ambient air respiration at 1370 m during rest, 20 min oxygen respiration, 20 min ambient air respiration at 1370 m, three maximal-effort breath holds spaced by 2 min, 10 min ambient air respiration, 5 min of cycling at 100 W, and finally 10 min ambient air respiration. We measured spleen volume by ultrasound and capillary hemoglobin (HB) concentration after each exposure, and heart rate (HR) and arterial oxygen saturation (Sao2) continuously. Mean (SD) baseline spleen volume was unchanged at 213 (101) mL before and 206 (52) mL after the climb. Before the climb, spleen volume was reduced to 184 (83) mL after three breath holds, and after the climb three breath holds resulted in a spleen volume of 132 (26) mL (p=0.032). After exercise, the preclimb spleen volume was 186 (89) mL vs. 112 (389) mL) after the climb (p=0.003). Breath hold duration and cardiovascular responses were unchanged after the climb. We concluded that spleen contraction may be enhanced by altitude acclimatization, probably reflecting both the acclimatization to chronic hypoxic exposure and acute hypoxia during physical work.


Assuntos
Adaptação Fisiológica/fisiologia , Suspensão da Respiração , Exercício Físico/fisiologia , Hemoglobinas/metabolismo , Montanhismo/fisiologia , Baço/fisiologia , Adulto , Altitude , Índices de Eritrócitos , Feminino , Frequência Cardíaca , Humanos , Masculino , Tamanho do Órgão , Oxigênio/sangue , Baço/anatomia & histologia , Baço/diagnóstico por imagem , Ultrassonografia
17.
Respir Physiol Neurobiol ; 182(2-3): 53-9, 2012 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-22588047

RESUMO

Acute dietary nitrate (NO3⁻) supplementation has been reported to lower resting blood pressure, reduce the oxygen (O2) cost of sub-maximal exercise, and improve exercise tolerance. Given the proposed effects of NO3⁻ on tissue oxygenation and metabolic rate, it is possible that NO3⁻ supplementation might enhance the duration of resting apnea. If so, this might have important applications both in medicine and sport. We investigated the effects of acute NO3⁻ supplementation on pre-apnea blood pressure, apneic duration, and the heart rate (HR) and arterial O2 saturation (SaO2) responses to sub-maximal and maximal apneas in twelve well-trained apnea divers. Subjects were assigned in a randomized, double blind, crossover design to receive 70 ml of beetroot juice (BR; containing ∼5.0 mmol of nitrate) and placebo juice (PL; ∼0.003 mmol of nitrate) treatments. At 2.5 h post-ingestion, the subjects completed a series of two 2-min (sub-maximal) static apneas separated by 3 min of rest, followed by a maximal effort apnea. Relative to PL, BR reduced resting mean arterial pressure by 2% (PL: 86±7 vs. BR: 84 ± 6 mmHg; P=0.04). The mean nadir for SaO2 after the two sub-maximal apneas was 97.2±1.6% in PL and 98.5±0.9% in BR (P=0.03) while the reduction in HR from baseline was not significantly different between PL and BR. Importantly, BR increased maximal apneic duration by 11% (PL: 250 ± 58 vs. BR: 278±64s; P=0.04). In the longer maximal apneas in BR, the magnitude of the reductions in HR and SaO2 were greater than in PL (P ≤ 0.05). The results suggest that acute dietary NO3⁻ supplementation may increase apneic duration by reducing metabolic costs.


Assuntos
Apneia , Suplementos Nutricionais , Nitratos/administração & dosagem , Adulto , Apneia/dietoterapia , Beta vulgaris/química , Método Duplo-Cego , Exercício Físico/fisiologia , Tolerância ao Exercício/efeitos dos fármacos , Tolerância ao Exercício/fisiologia , Feminino , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Raízes de Plantas/química , Capacidade Vital/efeitos dos fármacos
18.
Diving Hyperb Med ; 42(1): 4-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22437969

RESUMO

BACKGROUND: Splenic contraction associated with apnea causes increased haemoglobin concentration and haematocrit (Hct), an effect that may promote prolonged breath-holding. Hypoxia has been shown to augment this effect, but hypercapnic influences have not been investigated previously. METHODS: Eight non-divers performed three series of apneas on separate days after inspiration of oxygen with different carbon dioxide (CO2) levels. Each series consisted of three apneas 2 minutes apart: one with pre-breathing of 5% CO2 in oxygen (O2, 'Hypercapnia'); one with pre-breathing of 100% O2 ('Normocapnia'); and one with hyperventilation of 100% O2 ('Hypocapnia'). The apnea durations were repeated identically in all trials, determined from the maximum duration attained in the CO2 trial. A fourth trial, breathing 5% CO2 in O2 for the same duration as these apneas was also performed ('Eupneic hypercapnia'). In three subjects, spleen size was measured using ultrasonic imaging. RESULTS: Haemoglobin increased by 4% after apneas in the 'Hypercapnia' trial (P = 0.002) and by 3% in the 'Normocapnia' trial (P = 0.011), while the 'Hypocapnia' and 'Eupneic hypercapnia' trials showed no changes. The 'easy' phase of apnea, i.e., the period without involuntary breathing movements, was longest in the 'Hypocapnia' trial and shortest in the 'Hypercapnia' trial. A decrease in spleen size was evident in the hypercapnic trial, whereas in the hypocapnia trial spleen size increased, while only minor changes occurred in the other trials. No differences were observed between trials in the cardiovascular diving response. CONCLUSION: There appears to be a dose-response effect of CO2 on triggering splenic contraction during apnea in the absence of hypoxia.


Assuntos
Apneia/fisiopatologia , Hemoglobina A/metabolismo , Hipercapnia/fisiopatologia , Hiperventilação/fisiopatologia , Baço/fisiologia , Adulto , Apneia/sangue , Pressão Sanguínea/fisiologia , Dióxido de Carbono/administração & dosagem , Dióxido de Carbono/metabolismo , Mergulho/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Hematócrito , Humanos , Hipercapnia/sangue , Hiperventilação/sangue , Masculino , Tamanho do Órgão , Oxigênio/administração & dosagem , Oxigênio/metabolismo , Baço/anatomia & histologia
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