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Extreme preconditioning: Cold adaptation through sea swimming as a means to improving surgical outcomes

Article

Extreme preconditioning: Cold adaptation through sea swimming as a means to improving surgical outcomes

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Abstract

The practice of sea bathing for its health benefits was popularised by Richard Russell in Regency Brighton during the 18th Century. Although the cures he claimed it could effect seem a little far-fetched today, as with many historical remedies, there is much to be gained from revisiting such theories in the light of modern medical research. In this paper I will draw parallels between the surgical stress response and the response to cold exposure and hypothesise how a programme of sea bathing may be used to enhance postoperative recovery and reduce preoperative complications.

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... These health benefits are believed to be a consequence of the physiological responses to CWI and, particularly, alterations in these responses with cold water adaptation (Huttunen et al. 2004;Kukkonen-Harjula & Kauppinen, 2006). However, although controlled trials investigating the therapeutic use of CWI are lacking, there is a theoretical, physiological basis suggesting that this is an area worthy of investigation (Shevchuk, 2008;Harper, 2012). ...
... By reducing the magnitude of the stress response, some of the negative consequences of this may be reduced or avoided. Anecdotal evidence also exists of therapeutic benefit from cold water adaptation for conditions associated with chronically elevated levels of inflammation (Harper, 2012;Starr, 2013;Waters, 2016). ...
Article
https://theconversation.com/is-a-cold-water-swim-good-for-you-or-more-likely-to-send-you-to-the-bottom-89513
... These health benefits are believed to be a consequence of the physiological responses to CWI and, particularly, alterations in these responses with cold water adaptation (Huttunen et al. 2004, Kukkonen et al. 2006. However, while controlled trials into the therapeutic use of CWI are lacking, there is a theoretical, physiological basis suggesting that this is an area worthy of investigation (Shevchuk 2008;Harper 2012). ...
... By reducing the magnitude of the stress response, some of the negative consequences of this may be reduced or avoided. Anecdotal evidence also exists of therapeutic benefit from cold water adaptation for conditions associated with chronically elevated levels of inflammation (Starr, 2013;Harper, 2012;Waters, 2016). ...
Article
New findings: What is the topic of this review? This is the first review to look across the broad field of 'cold water immersion' and to determine the threats and benefits associated with it as both a hazard and a treatment. What advances does it highlight? The level of evidence supporting each of the areas reviewed is assessed. Like other environmental constituents, such as pressure, heat and oxygen, cold water can be either good or bad, threat or treatment, depending on circumstance. Given the current increase in the popularly of open cold water swimming, it is timely to review the various human responses to cold water immersion (CWI) and consider the strength of the claims made for the effects of CWI. As a consequence, in this review we look at the history of CWI and examine CWI as a precursor to drowning, cardiac arrest and hypothermia. We also assess its role in prolonged survival underwater, extending exercise time in the heat and treating hyperthermic casualties. More recent uses, such as in the prevention of inflammation and treatment of inflammation-related conditions, are also considered. It is concluded that the evidence base for the different claims made for CWI are varied, and although in most instances there seems to be a credible rationale for the benefits or otherwise of CWI, in some instances the supporting data remain at the level of anecdotal speculation. Clear directions and requirements for future research are indicated by this review.
... Results showed a relatively low prevalence of obesity in open water swimmers compared to the rest of the population, as regular swimming helped them to maintain healthy body weight (Crow et al. 2017). Finally, Harper (2012) hypothesized that in cases of surgical intervention, swimming in cold water may accelerate postoperative recovery and reduce pre-operative complications. ...
Article
Non-motorized water sports requiring physical efforts such as swimming, scuba diving, kayaking, sailing and surfing are becoming increasingly popular in Mediterranean marine protected areas (MPAs). This research investigates the relationship between these types of water sports and practitioners’ psychological and mental health. It takes the MPAs of Cap de Creus and Gulf of Roses (north-western Mediterranean) as a case study and is underpinned by a literature review and in-depth interviews with specialized water sports instructors. Results provide evidence that doing non-motorized water sports in the sea has positive outcomes for practitioners’ physical and mental health. When done in well-preserved areas, these sports may be a viable tool for both wellness and health recovery, and could be introduced in the community as a preventative and rehabilitation health strategy. This should be accompanied by strategies to address the ecological impacts these sports may have on MPAs.
... It has long been claimed that non-wetsuit cold water swimming (CWS) benefits health (1) , and anecdotally cold-water swimmers claimed to suffer fewer and milder infections, though this was not directly measured. A boost to immunity is biologically plausible: stress hormones are released during cold-water immersion (2) , and short-term stress may ready the immune system for injury or infection (3) . ...
Article
It has long been claimed that non-wetsuit cold water swimming (CWS) benefits health (1), and anecdotally cold-water swimmers claimed to suffer fewer and milder infections, though this was not directly measured. A boost to immunity is biologically plausible: stress hormones are released during cold-water immersion (2), and short-term stress may ready the immune system for injury or infection (3). However, very few studies have investigated immune system markers and/or actual illness in habitual cold-water swimmers.
... For instance, studies have found that cold exposure leads to the release of norepinephrine (Janský et al., 1996;Jedema et al., 2008;Jedema & Grace, 2003;Leppäluoto et al., 2008), which has been linked to the pathophysiology of mood and anxiety disorders (Ressler & Nemeroff, 1999), and plays an important role in the behavioral response to stress (Aston-Jones, Valentino, Van Bockstaele, & Meyerson, 1994;Foote, Bloom, & Aston-Jones, 1983). As with physical exercise, the release of norepinephrine suggests that cold immersion may be able to reduce inflammation, as norepinephrine can reduce TNF-α (Hu, Goldmuntz, & Brosnan, 1991), and macrophage inflammatory protein-1α (Haskó et al., 1998), and anecdotal evidence suggests that cold water adaptation can help relieve symptoms of conditions associated with chronic inflammation such as arthritis (Harper, 2012). Naturally, potential "cryotherapeutic" effects of surfing are likely to only emerge in colder conditions. ...
Article
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There is growing interest in surfing as a recreational activity that may facilitate skill development and improved mental health. However, there remains uncertainty regarding the causal processes through which surfing may improve psychological well-being. With the aim to guide future research, we review potential mechanisms that may underpin the psychotherapeutic effects of surfing. A range of plausible factors are identified, including exercise, water immersion, exposure to sunlight, transcendent experiences, reductions in rumination and the satisfaction of basic psychological needs. Further research is needed to clarify the effectiveness of surfing-based therapies and to establish the relative contributions of the causal mechanisms at play.
... They concluded that, through evidence of cold habituation occurring on both sides of the body, habituation is controlled more by central pathways as opposed to cutaneous receptors . Habituation has also been shown to attenuate responses to sudden cold water immersion, evidenced by reductions in sympathetic, tachycardia, and tachypnea responses (Kang et al., 1970;De Lorenzo et al., 1999;Vybiral et al., 2000;Huttunen et al., 2001;Westerlund et al., 2006;Barwood et al., 2007;Makinen et al., 2008;Li et al., 2009;Harper, 2012;Croft et al., 2013;Castellani and Young, 2016;Tipton, 2016). Habituation changes that lead to warmer skin, greater energy conservation, and improved comfort, with evidence suggesting that these originate more centrally than peripherally, may indeed have the ability to improve cognitive performance. ...
Article
Athletes, occupational workers, and military personnel experience cold temperatures through cold air exposure or cold water immersion, both of which impair cognitive performance. Prior work has shown that neurophysiological pathways may be sensitive to the effects of temperature acclimation and, therefore, cold acclimation may be a potential strategy to attenuate cold-induced cognitive impairments for populations that are frequently exposed to cold environments. This review provides an overview of studies that examine repeated cold stress, cold acclimation, and measurements of cognitive performance to determine whether or not cold acclimation provides beneficial protection against cold-induced cognitive performance decrements. Studies included in this review assessed cognitive measures of reaction time, attention, logical reasoning, information processing, and memory. Repeated cold stress, with or without evidence of cold acclimation, appears to offer no added benefit of improving cognitive performance. However, research in this area is greatly lacking and, therefore, it is difficult to draw any definitive conclusions regarding the use of cold acclimation to improve cognitive performance during subsequent cold exposures. Given the current state of minimal knowledge on this topic, athletes, occupational workers, and military commands looking to specifically enhance cognitive performance in cold environments would likely not be advised to spend the time and effort required to become acclimated to cold. However, as more knowledge becomes available in this area, recommendations may change.
Article
Background Outdoor swimming is increasingly popular, with enthusiasts claiming benefits to mental health. However, there is limited research into its effectiveness as an intervention for people with depression and/or anxiety. We aimed to establish recruitment rates and explore potential benefits, for a sea swimming course offered to people with depression and/or anxiety. Methods This was a singlearm, unblinded feasibility study. 61 participants, were recruited to an eight-session sea-swimming course. Attendance rates were recorded. Self-administered questionnaires were completed at baseline, post-course and at three-month follow-up. Free-text descriptions of thoughts about the course were collected using surveys, and 14 participants kept a diary. Results 53 participants (47 female, 5 male, 1 non-binary) were included in the final analysis. Overall attendance was 90.1%. There were reductions showing large effect (between d = 1.4 to 1.7) in the severity scores of both depression and anxiety between the beginning and end of the course. While severity scores marginally increased at three-month follow-up, a reduction from baseline scores for depression, anxiety (d = 1.2 and 1.4, respectively) and functioning scores (d = 0.8) remained. The qualitative analysis identified that ‘confronting challenges', ‘becoming a community’ and ‘appreciating the moment’ were key to the impact, or the 'mechanisms', that resulted in participants experiencing the 'outcomes' of ‘immediate positive changes in mood’, ‘improved mental and physical health’ and ‘increased motivation to swim’. Conclusions This study provides preliminary support for the engagement and acceptability of sea swimming as a novel intervention for depression and/or anxiety. Participants reported positive changes in mental health, indicating the intervention's potential as a public health resource. There was a clear gender difference, which requires further exploration. Larger scale trials are warranted.
Article
A 24-year-old woman with symptoms of major depressive disorder and anxiety had been treated for the condition since the age of 17. Symptoms were resistant to fluoxetine and then citalopram. Following the birth of her daughter, she wanted to be medication-free and symptom-free. A programme of weekly open (cold) water swimming was trialled. This led to an immediate improvement in mood following each swim and a sustained and gradual reduction in symptoms of depression, and consequently a reduction in, and then cessation of, medication. On follow-up a year later, she remains medication-free.
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To characterize fluid and ion shifts during a 4‐week cold adaptation period, six nonadapted volunteers underwent a cold acclimation program (CAP), which consisted of 1 hour head‐out immersion in water 14 ± 1°C three times a week. Blood samples were analyzed before and after immersion in the first and last weeks of CAR Urine was collected for 10 hours before, during, and for 3 hours after immersion. Plasma volume (PV) decreased during the first immersion (‐18%) and less after CAP (‐12%). Blood volume reduction was 8.5% before and 5.2% after CAP. Mean corpuscular volume was not changed either after the cold exposure or after the cold adaptation. The concentration of serum proteins increased by 12.1% after first immersion and by 8.1% after CAP. The changes in serum concentration of Na+, K+, and Cl‐ before and after CAP were not significant. Urine flow increased by 97% after the first immersion, and by 165% after CAR Urinary excretion of Na+ increased by 65% and 184% and of K+, by 122% and 262% during first immersion and after CAP, respectively. Serum concentration of aldosterone increased nonsignificantly (+30%) during immersion before CAP and it did not change after CAR A significant reduction in PV and an increased diuresis and elevated excretion of cations occurred after CAP.
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Simultaneous assessment of cardiac troponin I, B-type natriuretic peptide, and C-reactive protein has been found to provide unique prognostic information in acute coronary syndromes. The current study addressed the prognostic implication of a multiple-marker approach in cardiac surgery. Two hundred twenty-four patients undergoing cardiac surgery were included and followed up within 12 months after surgery. Serial blood samples were drawn in all patients the day before surgery, at the end of surgery, and 6, 24, and 120 h after surgery. Major adverse cardiac events within 12 months after surgery were chosen as study endpoints and were defined as malignant ventricular arrhythmia, myocardial infarction, congestive heart failure, the need for myocardial revascularization, and/or death from cardiac cause. Predictive ability of each cardiac biomarker was assessed using logistic regression. Accuracies of C-reactive protein, cardiac troponin I, and B-type natriuretic peptide, considered as continuous variables, to predict the occurrence of major adverse cardiac events were limited (area under receiver operating characteristic curve: 0.54 [0.47-0.60], P = 0.42; 0.62 [0.55-0.68], P = 0.01; and 0.68 [0.61-0.74], P < 0.001, respectively). When biomarkers were considered as 75% specificity dichotomized variables, elevated C-reactive protein (> 180 mg/l), cardiac troponin I (> 3.5 ng/ml), and B-type natriuretic peptide (> 880 pg/ml) were independent predictors of major adverse cardiac events (odds ratio: 2.14 [1.03-4.49], P = 0.043; 2.37 [1.25-5.64], P = 0.011; and 2.65 [1.16-4.85], P = 0.018, respectively) in a multivariate model including the European System for Cardiac Operative Risk Evaluation score. Simultaneous measurement of cardiac troponin I, B-type natriuretic peptide, and C-reactive protein improves the risk assessment of long-term adverse cardiac outcome after cardiac surgery.
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The present investigation is based on a 2.5 months selbstversuch (self-experiment) of the authors, between October 21 1992, and January 6 1993. 11 healthy students, five females and six males, age 24 to 29 years, and their teachers underwent regular winter swimming at least once a week, for 2 to 10 minutes, at the natural water temperature (6.8 degrees C (October 1992) to 2.0 degrees C (January 1993)) in the southern Baltic Sea. Blood samples were drawn before and 30 and 60 minutes after the cold bath, both at the first and the last day of the swimming season. TSH increased from 0.96 mU/l to 1.42 mU/l (p < 0.01) in the untrained, and from 0.93 mU/l to 1.43 mU/l (p < 0.01) in the cold-trained persons, and decreased thereafter (p < 0.01). Similar changes occurred in cortisol serum concentrations, though psychological stress seemed to interfere with cold stress. Cortisol increased from 99 ng/ml to 133 ng/ml in the untrained, and from 101 ng/ml to 137 ng/ml (p < 0.05) in the cold-trained persons within 30 minutes after cold water immersion, and decreased thereafter (p < 0.01). There were mild decreases in prolactin serum levels after cold stress, whereas FSH, LH and growth hormone remained unaltered. There was a mild initial elevation of serum glucose after cold stress (plus 12 mg/dl, (p < 0.01)) which disappeared after training. There were long term training effects besides the effects on glucose: Basal prolactin levels increased by almost the factor two, and insulin serum levels dropped by almost 50%.(ABSTRACT TRUNCATED AT 250 WORDS)
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Adaptation to oxidative stress is an improved ability to resist the damaging effects of reactive oxygen species, resulting from pre-exposure to a lower dose. Changes in uric acid and glutathione levels during ice-bathing suggest that the intensive voluntary short-term cold exposure of winter swimming produces oxidative stress. We investigated whether the repeated oxidative stress in winter swimmers results in improved antioxidative adaptation. We obtained venous blood samples from winter swimmers and determined important components of the antioxidative defense system in the erythrocytes or blood plasma: reduced and oxidized glutathione (GSH and GSSG), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat). The control group consisted of healthy people who had never participated in winter swimming. The baseline concentration of GSH and the activities of erythrocytic SOD and Cat, were higher in winter swimmers. We interpret this as an adaptative response to repeated oxidative stress, and postulate it as a new basic molecular mechanism of increased tolerance to environmental stress.
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This study examined the immunological responses to cold exposure together with the effects of pretreatment with either passive heating or exercise (with and without a thermal clamp). On four separate occasions, seven healthy men [mean age 24.0 +/- 1.9 (SE) yr, peak oxygen consumption = 45.7 +/- 2.0 ml. kg(-1). min(-1)] sat for 2 h in a climatic chamber maintained at 5 degrees C. Before exposure, subjects participated in one of four pretreatment conditions. For the thermoneutral control condition, subjects remained seated for 1 h in a water bath at 35 degrees C. In another pretreatment, subjects were passively heated in a warm (38 degrees C) water bath for 1 h. In two other pretreatments, subjects exercised for 1 h at 55% peak oxygen consumption (once immersed in 18 degrees C water and once in 35 degrees C water). Core temperature rose by 1 degrees C during passive heating and during exercise in 35 degrees C water and remained stable during exercise in 18 degrees C water (thermal clamping). Subsequent cold exposure induced a leukocytosis and granulocytosis, an increase in natural killer cell count and activity, and a rise in circulating levels of interleukin-6. Pretreatment with exercise in 18 degrees C water augmented the leukocyte, granulocyte, and monocyte response. These results indicate that acute cold exposure has immunostimulating effects and that, with thermal clamping, pretreatment with physical exercise can enhance this response. Increases in levels of circulating norepinephrine may account for the changes observed during cold exposure and their modification by changes in initial status.
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Epidemiological studies have shown an increase in acute myocardial infarctions or deaths due to myocardial infarction in colder weather; the mechanisms most likely involve increased blood levels of haemostatic risk factors, and increases in arterial blood pressure and heart rate. We studied the relationship between cold adaptation, haemostatic risk factors and haemodynamic variables. Cold adaptation was obtained by a programme of immersion of the whole body up to the neck in a water-filled bath, the temperature of which was gradually decreased from 22 degrees C to 14 degrees C, time of exposure being increased from 5 to 20 min over a period of 90 days. We studied 428 patients (44% men) and measured blood levels of fibrinogen, plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator antigen (t-PA), plasma viscosity, von Willebrand factor, D-dimer and platelet count, both at baseline and after 90 days of daily immersion. There were significant reductions in von Willebrand factor (-3%; p < 0.001), and plasma viscosity (-3.0 s; p < 0.001), and a mild but significant increase in PAI-1 (+0.3 IU/ml; p = 0.02). The pressure rate product (systolic blood pressure x heart rate) was also significantly lower after cold adaptation (-310; p = 0.004). Cold adaptation, compared with exposure to cold weather, induces different haemodynamic responses and changes of blood levels of haemostatic risk factors.
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Sudden immersion in cold water initiates an inspiratory gasp response followed by uncontrollable hyperventilation and tachycardia. It is known that this response, termed the "cold shock" response, can be attenuated following repeated immersion. In the present investigation we examined how long this habituation lasts. Twelve healthy male volunteers participated in the experiment, they were divided into a control (C) group (n = 4), and a habituation (H) group (n = 8). In October, each subject undertook two 3-min head-out seated immersions into stirred water at 10 degrees C wearing swimming trunks. These immersions took place at the same time of day, with 4 days separating the two immersions. In the intervening period, the C group were not exposed to cold water, while the H group undertook six, 3-min head-out immersions in water at 15 degrees C. Two months (December), 4 months (February), 7 months (May) and 14 months (January) after their first immersion, all subjects undertook another 3-min head-out immersion in water at 10 degrees C. The H group showed a reduction in respiratory frequency (47 to 24 breaths x min(-1)), inspiratory minute volume (72.2 to 31.3 1 x min(-1)) and heart rate (128 to 109 beats x min(-1)) during the first 30 s of immersion on day 5 compared to day 1. Seven months later these responses were still significantly reduced compared to day 1. After 14 months, heart rate remained attenuated but respiratory frequency and inspiratory minute volume had returned towards pre-habituation levels. The responses of the C group during the first 30 s of immersion were not altered. Both groups showed an attenuation in the responses during the remaining 150 s of immersion following repeated immersions. It is concluded that repeated immersions in cold water result in a longlasting (7-14 months) reduction in the magnitude of the cold shock response. Less frequent immersions produced a decrease in the duration, but not the magnitude of the response.
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There is compelling evidence that preconditioning occurs in humans. Experimental studies with potential clinical implications as well as clinical studies evaluating ischaemic, pharmacological and anaesthetic cardiac preconditioning in the perioperative setting are reviewed. These studies reveal promising results. However, there are conflicting reports on the efficacy of preconditioning in the diseased and aged myocardium. In addition, many anaesthetics and a significant number of perioperatively administered drugs affect the activity of cardiac sarcolemmal and mitochondrial KATP channels, the end‐effectors of cardiac preconditioning, and thereby markedly modulate preconditioning effects in myocardial tissue. Although these modulatory effects on KATP channels have been investigated almost exclusively in laboratory investigations, they may have potential implications in clinical medicine. Important questions regarding the clinical utility and applicability of perioperative cardiac preconditioning remain unresolved and need more experimental work and randomized controlled clinical trials. Br J Anaesth 2003; 91: 566–76
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Numerous studies have reported an increased mortality from coronary heart disease (CHD) during the winter.1–,5 Observational epidemiological data in England and Wales have shown that mortality from cardiovascular disease (CVD) increases linearly with decrease in diurnal minimum from 17 °C, accounting for about half of all excess cold-related mortality,1,,2 which is approximately 50 000 per year in Britain alone.3 This effect is particularly pronounced in the elderly, in whom there is a 30% increase in deaths from this cause. Mortality increases more with a given fall of temperature in regions with `warm' winters.6 These deaths may therefore represent a graded effect of mild to severe environmental cold, rather than a specific effect of severe cold stress. The short temporal relation between temperature drop and mortality observed in Taiwan, where ambient temperature fluctuates greatly, supports the hypothesis that temperature effect may be a major factor which contributes to the increased mortality in winter.7 Increased CVD mortality has been related to thrombosis due to haemoconcentration in the cold.8,,9 Mortality from CVD increased significantly with short-term falls in temperature. Short term falls in temperature also significantly increase blood pressure, haemoglobin (Hb), erythrocyte count, packed cell volume and serum albumin—changes that persist for 1–2 days.10 The secondary effects of winter respiratory infections may contribute to CVD deaths as observed during influenza epidemics,11 probably because of increases in blood fibrinogen during infections.12 However, most of the coronary deaths occur some hours after the exposure to cold, and before respiratory deaths increase.13 There is also epidemiological evidence for an increased incidence of strokes during winter, however, the data regarding the increase in case-fatality rate are somewhat equivocal.14 The decline in seasonality of coronary mortality in the US since 1970 …
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Long-distance swimmers swam in 10–14°C water on four days. Responses in blood pressure and rectal temperature were determined every day, and hormonal responses on the third day. Swimming time lengthened with the days and diastolic blood pressure after swimming was significantly lower on the fourth day than on the first day. In rectal temperatures there were great individual variations. Noradrenaline was elevated more in the thin swimmers. A lesser rise in diastolic blood pressure and the longer duration of swimming on the fourth day may point to habituation to the cold.
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Introduction The concept of fast-track surgery (enhanced recovery programs) has been evolved and been documented to be successful by decreasing length of stay, morbidity and convalescence across procedures. Future strategies However, there are several possibilities for further improvement of most of the components of fast-track surgery, where surgical stress, fluid and pain management are key factors. There is an urgent need for better design of studies, especially in minimal invasive surgery to achieve maximal outcome effects when integrated into the fast-track methodology.
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The impairment of insulin sensitivity, a marker of surgical stress, is important for outcomes. The aim was to assess the association between the quality of preoperative glycemic control, intraoperative insulin sensitivity, and adverse events after cardiac surgery. We conducted a prospective cohort study at a tertiary care hospital. Nondiabetic and diabetic patients scheduled for elective cardiac surgery were included in the study. Based on their glycosylated hemoglobin A (HbA(1c)), diabetic patients were allocated to a group with good (HbA(1c) <6.5%) or poor (HbA(1c) >6.5%) glycemic control. We used the hyperinsulinemic-normoglycemic clamp technique. The primary outcome was insulin sensitivity measurement. Secondary outcomes were major complications within 30 d after surgery including mortality, myocardial failure, stroke, dialysis, and severe infection (severe sepsis, pneumonia, deep sternal wound infection). Other outcomes included minor infections, blood product transfusions, and the length of intensive care unit and hospital stay. A total of 143 nondiabetic and 130 diabetic patients were studied. In diabetic patients, a negative correlation (r = -0.527; P < 0.001) was observed between HbA(1c) and intraoperative insulin sensitivity. Diabetic patients with poor glycemic control had a greater incidence of major complications (P = 0.010) and minor infections (P = 0.006). They received more blood products and spent more time in the intensive care unit (P = 0.030) and the hospital (P < 0.001) than nondiabetic patients. For each 1 mg x kg(-1) x min(-1) decrease in insulin sensitivity, the incidence of major complications increased (P = 0.004). In diabetic patients, HbA(1c) levels predict insulin sensitivity during surgery and possibly outcome. Intraoperative insulin resistance is associated with an increased risk of complications, independent of the patient's diabetic state.
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The hypothermic stress of immersion in cold water stimulates release of norepinephrine from the sympathetic nervous system. The speed and pattern of this response was studied in six healthy men by serial measurements of plasma norepinephrine concentrations before, during, and after 60 min of immersion in 10 degrees C water. After immersion for 2 min, the mean norepinephrine concentration was increased from 359+/-32 (basal) to 642+/-138 pg/ml and rose gradually to a maximum of 1.171+/-226 pg/ml after 45 min of immersion. Metabolic rate increased approximately threefold during the immersion period. After rewarming in warm water (40 degrees C), the subjects showed a transient peak in plasma norepinephrine followed by a rapid decrease to basal levels after 30 min. The fall in plasma norepinephrine after approximately 8 min of rewarming occurred despite persistent depression of the core temperature and coincided with a sudden decrease in metabolic rate and cessation of body shivering. These results suggest that the sympathetic nervous response to cold can be activated or suppressed very quickly and is dependent on the skin temperature.
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The responses to cold hand test (blood pressure increase and tachycardia) and to a cold face test (blood pressure increase and bradycardia) were used to study the role of the autonomic nevrous system in cold adaptation in humans. The Eskimos (men, women, children) were shown to have a very weak sympathetic response to cold but the vagal response (bradycardia) was identical to that of white people. A group of mailmen from Quebec city living outdoors approximately 30 h/wk throughout the year was also studied. A significant decline in the cold pressor response and an enhanced bradycardia (cold face test) were observed at the end of the winter. Similarly the fall in skin temperature of the cheek was not as pronounced when the measurements were made in May compared to those made in October. A group of soldiers was also studied before and after an Arctic expedition. It was found that the bradycardia of the cold face test was also more pronounced after sojourning in the cold. These results indicate that repeated exposures to severe cold in men activate some adaptive mechanisms characterized by a diminution of the sympathetic response and a concomitant enhancement of the vagal activation normally observed when the extremities and the face are exposed to cold.
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The influence of cold exposure on immune function is reviewed. Data obtained mainly on small mammals suggest that the acute effect of severe chilling is a suppression of several cellular and humoral components of the immune response, including a decrease of lymphocyte proliferation, a down-regulation of the immune cascade, a reduction of natural killer (NK) cell count, cytolytic activity, activation of complement, and the induction of heat shock proteins. However, adaptation to a given cold stimulus appears to develop over the course of 2-3 weeks. Further work is needed to examine interactions between cold exposure and exercise, and to determine whether the disturbances of immune response are sufficient to impair immunosurveillance in human subjects.
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Recently, a marked increase in the number of acute myocardial infarction cases during winter has been reported. Approximately 53 % more cases were reported in winter than during summer [1]. The abrupt rupture of atherosclerotic plaques that occurs during cold exposure has been associated with an increase in sympathetic tone that causes increased blood pressure, heart rate and cardiac workload [2]. The aim of our study was to investigate the effects on blood pressure and heart rate of sudden exposure to cold water (14 ∞C for 20 min) after 90 days of short intermittent exposure to cold water in 259 men and women. The cold adaptation was obtained by a programme of immersion of the whole body up to the neck in a waterfilled bath, the temperature of which was decreased gradually from 22 ∞ Ct o 14∞C. The time of exposure was increased from 5 to 20 min over a period of 90 days. The programme was designed in four stages : the first three gradually acclimatize the body to water temperature, and the last is the re-warming phase. The stages were as follows : (1) acclimatization of the feet to cold water and touch ; (2) acclimatization of the lower half of the body to cold water ; (3) total body immersion (the duration of this stage varied from 5 to 20 min) ; (4) re-warming phase. Table 1 presents the results for arterial blood pressure, heart rate and the rate pressure product (systolic blood pressure‹heart rate) at baseline and immediately after the head-out water immersion for 20 min at 14 ∞C. The heart rate and the pressure rate product were significantly reduced in these cold-adapted men and women after
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Elective surgery causes a marked, transient reduction in insulin sensitivity. The degree of the reduction is related to the magnitude of the operation. The type and duration of surgery performed, perioperative blood loss, and also the degree of postoperative insulin resistance have significant influences on the length of hospital stay. A novel approach to minimize insulin resistance after surgery is being presented and suggests that simply pretreating the elective surgical patient with sufficient amounts of carbohydrates instead of fasting can significantly reduce postoperative insulin resistance. It is not clear which mediators are the most important for the development of insulin resistance after surgery. Nevertheless, marked insulin resistance can develop after elective surgery without concomitant elevations in cortisol, catecholamines or glucagon. The main sites for insulin resistance seem to be extrahepatic tissues, probably skeletal muscle, where preliminary data suggest that the glucose transporting system is involved.
Article
The cytokine response after thermal stress (sauna + swimming in ice-cold water) was investigated in subjectively healthy persons. Two groups were studied at the end of the winter season: habitual and inexperienced winter swimmers. Blood was collected at rest, after a sauna bath and after a short swim in ice-cold water. Conventional methods and ELISA kits were used to determined the blood picture, serum cortisol and dehydroepiandrosterone sulphate, plasma anti-diuretic hormone (ADH) levels, and the levels of several cytokines in plasma and in the supernatants of blood cell cultures which were stimulated with lipopolysaccharide (LPS). In regular winter swimmers, the concentrations of plasma interleukin 6 (IL-6), leukocytes, and monocytes at rest were significantly higher than in inexperienced subjects. In experienced female winter swimmers, the plasma concentration of the soluble receptor for IL-6 was significantly lower than in inexperienced female swimmers. In both groups, granulocytosis, haemoconcentration and significant increases in the concentrations of ADH, cortisol and IL-6 were observed after the stimuli. However, the changes in the cortisol concentration were dramatically larger in habitual winter swimmers. A significant correlation was found between the delta values of cortisol and the basal concentrations of IL-6. In cell cultures, the LPS-induced release of IL-1beta and IL-6 was higher at rest in the inexperienced winter swimmers. This release was dramatically suppressed after exposure to the stimuli in the inexperienced winter swimmers but tended to increase in the regular winter swimmers. These stresses appear to challenge both the neuro-endocrine and the immune systems and the results indicate that adaptive mechanisms occur in habitual winter swimmers.
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Changes in plasma levels of norepinephrine, dopamine-β-hydroxylase (DβH), and renin activity were observed in nine healthy volunteers during cold pressor stimulation. Increases in mean arterial blood pressure and heart rate during cold stimulation were accompanied by a sharp rise in plasma norepinephrine, while plasma DβH and renin activity showed little or no change. The results indicate that plasma norepinephrine accurately reflects acute activation of the sympathetic nervous system in contrast to plasma DβH and renin activity.
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In the current era cardiac surgeons are being called upon to operate upon older, sicker patients. The effect is to augment oxidative stress and increase the rate of post-operative complications and ultimately mortality. We have developed antioxidant-based pre-treatment regimes initially based on coenzyme Q(10). A randomised trial of coenzyme Q(10) in elective cardiac surgery patients demonstrated augmented plasma and cardiac mitochondrial membrane coenzyme Q(10) content, improved mitochondrial respiration and increased myocardial tolerance of oxidative stress. The addition of omega-3 polyunsaturated fatty acids, alpha-lipoic acid, selenium and magnesium orotate in a second clinical trial, improved post-operative recovery with demonstrable reductions in myocardial damage, rate of atrial fibrillation and length of hospital stay. Finally we performed a pilot study of this combined metabolic therapy regimen to which we added preoperative physical exercise and mental stress reduction with indications of further improvements in post-operative recovery. We conclude that simultaneously targeting a number of key deficiencies with a metabolic formulation prior to surgery results in peri- and post-operative clinical and economic benefits.