Harald Engan

Acute dietary nitrate supplementation improves dry static apnea performance.

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.

Impact of symptoms of anxiety and depression on COPD Assessment Test scores

Anxiety and depression are common comorbidities in patients with chronic obstructive pulmonary disease (COPD) and affect patients’ health status [1, 2]. Health status in COPD patients is frequently assessed by the St George’s Respiratory Questionnaire (SGRQ), which is a validated disease-specific questionnaire widely used in clinical trials [3], but complex and time-consuming to complete and score. Consequently, the COPD Assessment Test (CAT) has been developed [4]. This is a disease-specific health status questionnaire containing eight items with good sensitivity, reliability and responsiveness [4]. CAT scores are strongly positively correlated with SGRQ scores in patients with COPD [4]. Therefore, it is reasonable to hypothesise that those COPD patients with symptoms of anxiety and/or depression will report higher CAT scores (equalling worse health status) compared to those without symptoms. The latest version of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) document [5] recommends the CAT as a tool to assess the impact of COPD on the individual patient beyond airflow limitation. Although it was known that clinically relevant symptoms of anxiety and depression are more common in patients in GOLD stage IV compared to patients in GOLD stages I and II [1], the frequency distribution of patients with symptoms of anxiety and depression across the updated GOLD classification remains unknown. Recently, Sillen et al. [6] reported a prevalence of symptoms of anxiety and depression of 38% and 32%, respectively, in COPD patients with GOLD group D. We aimed to assess …

The Effect of Climbing Mount Everest on Spleen Contraction and Increase in Hemoglobin Concentration During Breath Holding and Exercise

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.

Are web-based questionnaires accepted in patients attending rehabilitation?

Abstract 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.

Blood lactate accumulation during competitive freediving and synchronized swimming.

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.