Kategoriarkiv: Forskning og artikler

Ukjent sin avatar

The fascia: the forgotten structure.

av

Nyeste oppdateringen om bindevet her, som gir en klar definisjon av hva det faktisk er. Nevner forholdet mellom superficial og deep facia.

Dropbox fil her: https://dl.dropboxusercontent.com/u/17457302/Forskning%20mappe%20for%20terapi/The%20fascia%20-%20the%20forgotten%20structure.pdfAbstract: http://www.ncbi.nlm.nih.gov/pubmed/22852442

In 1987, Myers wrote: “the traditional approach that studies the muscles as inde- pendent units, has been a barrier to understand the bigger picture of fascial func- tion”. Indeed, the whole musculoskeletal system is usually studied only with respect to its bone and muscle components, the fasciae being traditionally relegated to the role of deftly holding ‘parts’ together.

It is increasingly evident that the fasciae may play important roles in venous return (Caggiati, 2000), dissipation of tensional stress concentrated at the sites of entheses (Benjiamin et al., 2008), etiology of pain (Langevin et al., 2001; Langevin, 2006), interactions among limb muscles (Huijing et al., 1998; Huijing, 1999; Huijing and Baan, 2001a,b; Yucesoy et al., 2006) and movement perception and coordina- tion (Vleeming et al., 1995, 1996; Stecco L., 1996, 2004; Stecco L. and Stecco C., 2009), due to their unique mechanical properties and rich innervation. Huijing et al. (2003) showed that only 70% of muscle tension transmission is directed through tendons, which thus definitely play a mechanical role, but 30% of muscle force is transmitted to the connective tissue surrounding muscles, highlighting the role of the deep fasciae in the peripheral coordination of agonist, antagonist and synergic muscles. The many functions of the fasciae include the roles of the ectoskeleton for muscle attachments and protective sheets for underlying structures (Wood Jones, 1944; Benjiamin, 2009). Lastly, recent studies have emphasized the continuity of the fascial system between regions, leading to presume its role as a body-wide proprioceptive/communicating organ (Langevin, 2006; Langevin et al., 2006; Lindsay, 2008; Kassolik et al., 2009).

This ample list of functions partly also derives from the fact that the term ‘fas- cia’ has been applied to a large number of very different tissues, ranging from well- defined anatomical structures, such as the fascia lata, thoracolumbar fascia, plantar and palmar fasciae, and cervical and clavipectoral fasciae, to the loose packing tissues which surround all the moving structures within the body. In fact, according to the American Heritage Stedman’s Medical Dictionary (2007), a fascia is “a sheet or band of fibrous connective tissue enveloping, separating, or binding together muscles, organs, and other soft structures of the body”, so that only the well-defined fibrous connective tissue layers may appropriately be called “fascia”, and it is consequently incorrect to use this term to mean all the connective tissue of the body.

Functionally, the superficial fascia may play a role in the integrity of the skin and support for subcutaneous structures, particularly veins, by ensuring their patency.

The deep fascia is a fibrous membrane forming an intricate network which envel- ops and separates muscles, forms sheaths for nerves and vessels, strengthens liga- ments around joints, and binds all the structures together into a firm compact mass. The deep fasciae envelop all the muscles of the body, but have different features according to region.

Under the deep fascia, the muscles are free to slide because of their epimysium. Loose connective tissue rich in hyaluronic acid lies between the epimysium and the deep fasciae (McCombe et al., 2001).

In the last few years, several studies have demonstrated the presence of many free, encapsulated nerve endings, particularly Ruffini and Pacini corpuscles, inside the deep fasciae (Stilwell, 1957; Yahia et al., 1992; Stecco C. et al., 2007), although dif- ferences exist according to the different regions; retinacula seem to be the most highly innervated structures. Analysis of the relationship between these nerve endings and the surrounding fibrous tissue shows that the corpuscle capsules and free nerve end- ings are closely connected to the surrounding collagen fibers, indicating that these nerve endings may be stretched, and thus activated, every time the surrounding deep fascia is stretched.

Some recent studies have reported possi- ble alterations of the retinacula (Demondion et al., 2010), particularly in ankle sprain outcomes (Stecco A. et al., 2011), in that they sometimes show more intense signal ascribable to local edema and inflammation; in patellofemoral malalignment, the medial and lateral retinacula of the knee show different thicknesses and/or degrees of tension. Despite these data, the fascial system is usually not analysed, by either radiologists or surgeons, and only a few papers report the visualization of possible alterations of the fasciae.

Ukjent sin avatar

Investigation of the mechanical properties of the human crural fascia and their possible clinical implications.

av

Om at bindevevet kan endres med stretching over 120s, og kan dermed redusere sitt «stress» med 40%.

http://www.ncbi.nlm.nih.gov/pubmed/23793789

The stress relaxation tests showed that the crural fascia needs 120 s to decrease stress of 40 %, suggesting a similar time also in the living so that the static stretching could have an effect on the fascia

Ukjent sin avatar

You said biomechanics? Its «fuzzy» mechanics!!

av

Dekonstruksjon av biomekanikk paradigmet og hvordan det ikke passer inn i vår organisme.

http://www.maitrise-orthop.com/corpusmaitri/orthopaedic/mo64_fuzzy_mechanics/index.shtml

The acquired reflex to think according to Mechanics must absolutely be lost when dealing with Biomechanics. That is the reason why with some exceptions, engineers in Industrial Mechanics may sometimes be poor biomechanics. In fact, Biomechanics deals with a four dimensional space, where «the time dimension» does not have the same value as that involved in Industrial Mechanics.

Ukjent sin avatar

What nervous systems do: early evolution , inputoutput, and the skin brain thesi s

av

Viktig studie som hinter til den virkelige oppgaven til nervesystemet, som ikke er sende info inn til eller ut fra hjernen… Om vitenskapens forstelse av nervesystemet opp igjennom tidene og hvordan alt vi trodde om nervesystemet er feil.
http://adb.sagepub.com/content/21/2/67.abstract
Hele studien på dropbox: https://dl.dropboxusercontent.com/u/17457302/Forskning%20mappe%20for%20terapi/Keizer%202013%20What%20nervous%20systems%20do-%20early%20evolution%2C%20input%C2%96output%2C%20and%20the%20skin%20brain%20thesis.pdf

We hold that the fundamental problem here was not so much to act intelligentlya problem that had already been solved in various ways without a nervous system (Section 3.3)but to act as a single multicellular unit.

Nervous systems arose as a source and coordinator of patterned activity across extensive areas of contractile tissue in a way that was only loosely constrained by sensor activity.

In this view, the central direction of nervous system connections runs transverseat right anglesto the through-conducting stream that runs between sensors and effectors: early nervous systems evolved as connec- tions across a contractile tissue and in close connection to the animal epithelium or skin.

Adopting the phrase skin brain introduced by Holland (2003), we will refer to this idea as the skin brain thesis, or SBT.

Although the inputoutput view is deeply entrenched, there are issues involving nervous system functioning that are highly puzzling or awkward when the input output view is taken as a fundamental account of ner- vous systems.

The current inputoutput interpretation of nervous sys- tems is closely linked to a computational information- processing interpretation. This linkage is intrinsic to the classic neuron doctrine, according to which neurons are individual entities that receive and send electrical signals to one another through synapses in an all-or-none fashion that is basically similar to electrical switches. Consistent with the neuron doctrines one-way flow of information, nervous systems could be interpreted as electronic circui- try, which may be far more complex than artificial circui- try, but not intrinsically different.

The problem with this input-output interpretation is that the neuron doctrine on which it is based has been seriously undermined (e.g., Bullock et al., 2005; Guillery, 2007; Kruger & Otis, 2007) since it was first advanced by Ramon y Cajal in the late 19th century. Famously, Cajal formulated what came to be called the neuron doctrine explicitly in opposition to the then-current idea that ner- vous systems are reticular organizations of nerve cells directly connected to one another, through which electri- cal activity flows diffusely in all directions (Guillery, 2007; Kruger & Otis, 2007).

The neu- ron doctrine can not plausibly explain the diversity of neuromodulatory substances, such as amines and neu- ropeptides, that remodel neuron behavior and circuitry within minutes and hours instead of the standard milli- second time scale (Bullock et al., 2005). Many of these neuromodulatory molecules are not recent evolutionary developments but have a deep genomic history. More recently, immune system elements, such as cytokines, have been shown to play critical roles in modulating neural plasticity under normal as well as challenged conditions (McAfoose and Baune, 2009; Yirmiya and Goshen, 2011), and these associations are also very old (Maier and Watkins, 1998). The neuron doctrine cannot explain these associations either. Moreover, in many neurons, action potentials can travel backward from the axon and cell body to the dendrites.

Clue 2: The detailed operation of neurons and nervous sys- tems is much more complex and diverse than can be readily accounted for by the inputoutput view.

Clue 3: The reflex arc organization may very well be a sec- ondary optimization of nervous systems.

The inputoutput interpretation stresses that nervous systems function as information processing devices. However, in recent years serious claims concerning the complexity, and even cognitive, nature of the behavior of single-celled organisms have come to the fore. For example, John Allman (1999) discusses how the most fundamental features of brains such as sensory integra- tion, memory, decision-making, and the control of behavior, can already be found in simple organisms such as bacteria (pp. 56).

While this is presumably true of complex ner- vous systems, the point does not seem to apply to basic forms. When one systematically compares organisms with basic nervous systems, they do not show more complex behavior than creatures without a nervous sys- tem.

According to Jennings, the possession of a nervous system brings with it no observable essential changes in the nature of behavior. We have found no important additional features in the behavior when the nervous system is added (p. 263).

Clue 4: Basic nervous systems do not lead to more complex behavior than is often present in organisms without a nervous system.

Clue 5: Many of the biomolecular characteristics of neurons are already present in non-neural precursor contexts.

Clue 6: Understanding what nervous systems do is a question that requires an answer at the level of the whole animal.

Clue 7: The main animal effector consists of muscle tissue that requires spatiotemporal coordination.

Clue 8: Coordinating extensive areas of muscle tissue requires endogenous activity.

Nowadays, the picture has changed again. While Mackies scenario for the origins of nervous systems is still influential (e.g., Arendt, 2008; Je kely, 2011; Miller, 2009), it faces important difficulties. A key problem is that nervous systems are found more widely among animal phyla and classes than electri- cally coupled conductive epithelia. Notably, while all four major cnidarian classes have a nervous system, there is substantial evidence that only the Hydrozoa have functional gap junctions (Mackie, Anderson, & Singla, 1984; Satterlie, 2011).

Clue 9: Chemical transmission between adjacent cells can have provided the basis for primitive conductive epithelia that formed a half-way station to nerve nets.

Clue 10: Chemically transmitting conductive (myo)epithelia can have provided a basic form of muscle coordination.

Clue 11: Specialized axodendritic connections can have sub- sequently evolved to broaden the existing possibilities for muscle coordination.

Under this interpretation, the core business of such nerve nets consisted of organizing and integrating activity across contractile effector surfaces (e.g., mus- cle) spread out beneath an external epithelium. Such a task would involve parallel organization and coordina- tion requiring signaling across a surface rather than a through-conducting, sequential organization based on a set of pre-existing sensors and effectors. No stimulus can specify by itself the behaviorally relevant contrac- tion patterns across such a surface. Patterns that workthat is, patterns that lead to movements that are appropriate under the circumstancesare a func- tion of the particular effector surface that is present in the animals rather than of any triggering stimulus. Also, based on what we know about organisms today, movement is likely to have been self-induced, while external stimuli acted rather as modulating factors on continuous effector activity.

While modern nervous sys- tems have various other functions, it is evident that enabling an organism to move and manipulate its envi- ronment in specific ways is the prime reason for the huge investment in these metabolically expensive organs (Allman, 1999).

Such cellular con- tractions must be coordinated with respect to one another, however. Uncoordinated contractions by indi- vidual cells would not result in whole-body motility. This, we believe, is where nervous systems come in. Nerve nets are intrinsically tied up with muscle surfaces.

The SBT can now be formulated as the proposition that early nerve nets evolved when some conducting cellseither within or connected to the myoepithelium evolved elongated processes and synaptic connections in a way that modified and enhanced the patterning capabil- ities of a pre-existing myoepithelium. Rather than pro- viding specific connections from sensors to effectors, the proper function of such nerve nets was to control, modify and extend the available self-organized pattern- ing across a Pantin surface. The key adaptation pro- vided by early nerve nets was the way in which they added to the generic self-organizing properties of pre- existing epithelial and muscular tissues.

To summarize, the SBT claims that nerve nets origi- nated as a new mechanism by which Pantin surfaces could be more intricately and flexibly patterned to accommodate efficient motility at larger bodily scales. At a fundamental level nerve nets are fitted to spatial patterning and to accommodating spatially patterned feedback.

The SBT offers a genuinely new conceptual approach for understanding nervous systems at a whole systems level. Starting with the most primitive neural organiza- tionsproto-neural myoepithelia and nerve netswe argue that both are characterized by connections trans- verse to the standard sensor-effector direction and evolved their characteristics to bind the many cellular units of muscle sheets together into a unitary system. Nervous systems are in this view not organized aroundor rather betweensensors and effectors. They are themselves a precondition for both extended con- tractile effectors as well as multicellular sensory arrays.

We have stressed from the beginning that the SBT provides a conceptual reinterpretation of nervous system functioning.

The skin brain pro- posal casts animal behavior as a dynamical phenotype, necessarily tied to the species or class of animals under consideration. Sherrington once observed that posture follows movement like a shadow (Stuart, 2005). We would like to stress that dynamically changing body pos- ture is a precondition for all task-oriented animal beha- vior. Animal behavior is a part of animal organization.

Ukjent sin avatar

Melatonin as an antioxidant: biochemical mechanisms and pathophysiological implications in humans

av

Viktig studie som nevner alt om hvordan melatonin virker som en antioksidant. Hele studien er her, men den er ikke gjennomgått enda.

http://www.actabp.pl/pdf/4_2003/1129s.pdf

Melatonin’s functions as an antioxidant include: a), direct free radical scavenging, b), stimulation of antioxidative enzymes, c), increasing the efficiency of mitochon- drial oxidative phosphorylation and reducing electron leakage (thereby lowering free radical generation), and 3), augmenting the efficiency of other antioxidants.

Ukjent sin avatar

Melatonin induces γ- glutamylcysteine syn thetase mediated by activator protein-1 in human vascular en dothelial cells

av

Det første bildet viser hvordan melatonin dobler glutathion konsentrasjon. Dette er interessant med tanke på at diafragmiske pust øker melatonin. Melatonin hemmer enzymet som bryter ned glutathion, derfor økes konsentrasjonen.

http://www.sciencedirect.com/science/article/pii/S0891584999001318

In the present study, we show that melatonin induces the expression of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme of glutathione (GSH) synthesis, in ECV304 human vascular endothelial cells.

As conclusion, induction of GSH synthesis by melatonin protects cells against oxidative stress and regulates cell proliferation.

Ukjent sin avatar

Physical tests for shoulder impingements and local lesions of bursa, tendon or labrum that may accompany impingement

av

Stor studie om det aller meste rundt forskjellige diagosekriterier og individuelt det er fra terapeut til terapeut, men også fra studie til studie.

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007427.pub2/full

Shoulder pain and dysfunction are common in the general population. A systematic review reported point prevalences for shoulder pain ranging from 7% to 26% with some indication that prevalence increases with age (Luime 2004a). Data from the US National Ambulatory Medical Care Survey (NAMCS) 1993 to 2000 indicate that one per cent of all office visits to physicians are for shoulder pain, and that a quarter of these visits are to primary care physicians (Wofford 2005). Moreover, shoulder pain has little tendency to resolve quickly or completely; according to a Dutch study, one half of all sufferers still report problems a year after their initial consultation (Van der Heijden 1997).

Impingement was originally characterised by Neer and Welsh (Neer 1977) as pinching of the soft-tissue structures between the humerus (upper arm bone) and the bone-and-ligament coraco-acromial arch of the scapula (shoulder blade) on movement. These structures include the contents of the so-called subacromial outlet: the ‘rotator cuff’ of muscles and tendons that surrounds the shoulder joint and the large lubricating sac (the subacromial bursa) that overlies it; and also the biceps tendon, which arches over the humerus, deep to the rotator cuff and within the shoulder joint itself. Neer 1977 proposed a continuum of impingement severity, from irritation of the bursa and cuff (normally due to overuse, and reversible by conservative management) to full thickness tears of the cuff. It has since been theorised that any abnormal reduction in the subacromial outlet’s volume (e.g. by bone shape, soft-tissue thickening, posture or minor joint instability) may predispose to, contribute to, perpetuate or aggravate this train of events (discussed by Hanchard 2004).

When a person presents with a history and symptoms suggestive of shoulder impingement, the clinician performs a series of physical (non-invasive) tests that aim to establish the diagnosis, and inform treatment and prognosis. Such tests may include the ‘painful arc’ test, intended to identify impingement in general terms (Cyriax 1982); tests to identify subacromial impingement (e.g. Neer 1977) or internal impingement (e.g. Meister 2004); tests to differentiate subacromial from internal impingement (Zaslav 2001); tests to diagnose rotator cuff involvement, including tears (e.g. Gerber 1991a; Gerber 1996; Hertel 1996a), or biceps tendon involvement (e.g. Yergason 1931); or tests to diagnose glenoid labrum tears (e.g. Kim 2001; Liu 1996b; O’Brien 1998a). These tests are described in Table 1, and include tests that were identified in studies included in this review.

Physical tests involve clinical and interpretative skills, and results have been shown to differ with testers’ expertise (Hanchard 2005). This has implications for the generalisation of results relating to test performance from individual studies.

Other tests, usually conducted subsequently and in secondary care settings by specialists, include ultrasonography, arthrography, bursography, magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA). Those considered as potential reference standards for this review are described in Table 3. Some of these tests are invasive and none is completely valid (Dinnes 2003). Specifically, the generally accepted gold standard of diagnosis, direct observation at open or arthroscopic (‘keyhole’) surgery (Table 3), is not completely valid because tears within the substance of the rotator cuff are not directly visible (Fukuda 2003) and conversely, visible tears may be asymptomatic (Dinnes 2003; MacDonald 2000a; Milgrom 1995; Sher 1995). Surgery carries a risk of complications (Blumenthal 2003;Boardman 1999; Borgeat 2001), and is not applicable in the primary care setting where the majority of consultations and treatment prescriptions occur. Moreover, approximately 70% of patients with shoulder impingement respond to conservative treatment (Morrison 1997a) and so those having surgery cannot be considered representative (spectrum bias).

Whether intentional or unintentional, variations in index tests’ procedure or interpretation were prevalent, such that, as observed above, there were only six instances of any index test being performed and interpreted (in terms of criteria for, and implications of, a positive result) similarly in two studies; and no instances of three studies or more using any one test similarly.

Between-tester agreement

Few studies addressed this aspect, although it is fundamental to the validity of clinical tests. Agreement is best evaluated using the kappa coefficient, since this takes account of the fact that agreements may occur by chance. The coefficient ranges from 0 to 1, and interpretation has been recommended as follows by Altman 1991: less than 0.20 = poor; 0.21 to 0.40 = fair; 0.41 to 0.60 = moderate; 0.61 to 0.80 = good; 0.81 to 1 = very good. By these criteria, and based on point estimates, very good between-rater agreement was achieved for only one test, the biceps load II test (Kim 2001). Good agreement was obtained for the passive compression test (Kim 2007b) and resisted lateral rotation from neutral rotation (Michener 2009). Agreement for the painful arc test was moderate (Michener 2009), while that for Neer’s test was fair to moderate (Michener 2009; Razmjou 2004). For the empty can test (Michener 2009) and Hawkins’ test (Michener 2009; Razmjou 2004), agreement was only fair.

There is insufficient evidence upon which to base selection of physical tests for shoulder impingements, and local lesions of bursa, tendon or labrum that may accompany impingement, in primary care.The large body of literature revealed extreme diversity in the performance and interpretation of tests, which hinders synthesis of the evidence and/or clinical applicability.

Ukjent sin avatar

Pasient fikk 31 diagnoser

av

Artig artikkel om hva som skjer når 100 leger skal sette diagnose på samme pasient: 31 forskjellige diagnoser.

http://www.dagensmedisin.no/nyheter/-pasient-fikk-31-diagnoser/

Vanligste diagnose var psykiske lidelser, generelle uspesifikke helseplager og muskel- og skjelettlidelser. Flertallet ble henvist til psykologisk behandling, hos fastlege eller hos spesialist. Nesten 60 prosent av legene ga ulik hoved- og sekundærdiagnose.

Ukjent sin avatar

Apnea: A new training method in sport?

av

Veldig viktig studie om hva dykkeres trening i Apnea (å holde pusten) kan bidra med i annen idrett. Bekrefter det meste av det jeg har skrevet om, men oppklarer noe om blodverdier bl.a. Nevner EPO, nyrenes tilpasning, hypoxi, HIF-1, melkesyre, lungevolum

http://www.univ-rouen.fr/servlet/com.univ.utils.LectureFichierJoint?CODE=1307716204012&LANGUE=0

http://www.ncbi.nlm.nih.gov/pubmed/19850416

Breath-hold divers have shown reduced blood acidosis, oxidative stress and basal metabolic rate, and increased hematocrit, erythropoietin concentration, hemoglobin mass and lung volumes. We hypothesise that these adaptations contributed to long apnea durations and improve performance. These results suggest that apnea training may be an effective alternative to hypo- baric or normobaric hypoxia to increase aerobic and/or anaerobic performance.

Apnea durations clearly increase with training. Perhaps less well known are the findings that apnea train- ing also increases hematocrit (Hct), erythropoietin (EPO) concen- tration, hemoglobin (Hb) mass, and lung volumes [2–5]. In addition, blood acidosis and oxidative stress were shown to be re- duced after three months of apnea training [6,7]. Therefore, why not encourage apnea training for athletes?

The major determinant of aerobic performance is the capacity to deliver oxygen to the tissues [8]. An increase in the total amount of erythrocytes, as reflected by increased Hct and Hb mass, is med- iated by the glycoprotein hormone EPO, which is predominantly synthesized by the kidneys in response to chronic hypoxia [9] and to some extent (10–15% of total production) by the liver. EPO stimulates the proliferation and maturation of red blood cell precursors in bone marrow, increasing oxygen delivery to muscle and thereby enhancing sports performance [9].

(hypoxic or ischemic conditions) results in a stabilization of the transcription factor hypoxia-inducible factor (HIF)-1a, which increases EPO secretion and the expression of EPO receptor [10].

Furthermore, any training effect vanishes rapidly (two weeks), as the newly formed red cells disappear within a mat- ter of days due to neocytolysis.

The splenic contraction effect

Apnea training may well be a future training method. Splenic contraction has been described in marine mammals as improving oxygen transport, through an increase in circulating erythrocytes. Its consequence is a prolonged dive without injuries. In humans, repeated apneas (five, in general) induce splenic contraction. This increases Hct and Hb (both between 2% and 5%) independently of hemoconcentration [19] and reduces arterial oxygen desaturation, thereby prolonging the apnea duration [3,19–22].

Repeated apneas are known to induce hypoxemia in the spleen and kidney, increas- ing respectively Hct and Hb and serum EPO concentrations [2,23].

First, the splenic contraction develops quickly after three or four apneas separated by two minutes of recovery and is associ- ated with a transient increase in Hb concentration. The amplitude of the spleen volume reduction after repeated apneas, with or without face immersion, varies widely (20–46%) depending on the rate of change in oxygenation [3,19,22,25–27]. The rapidity of the splenic contraction after simulated apneas strongly suggested a centrally-mediated feed-forward mechanism rather than the influ- ence of slower peripheral triggers [19]. These spleen and Hb re- sponses may be trainable.

Second, DeBruijns et al. [2] recently observed that repeated apneas increased EPO concentration by 24%, with the peak value reached 3 h after the last apnea and a return to baseline 2 h later.

The rapid reduction in tissue oxygen levels that oc- curs during apneas has been suggested to stimulate enhanced EPO production [25]. The decreased kidney blood flow induced by apneic vasoconstriction would result in local ischemic hypoxia, stimulating kidney EPO production. Similarly, obstructive sleep ap- nea increases the levels of EPO (􏰀1.6) and Hb (+18%) [24].

The lower SaO2 decrease found in trained divers after repeated apneas may account for the reduced oxygen delivery because of the diving response (bradycardia and vasocon- striction) and/or an increase in oxygen content [1].

Long term-effects

Another important consideration is the persistence of the per- formance gains. Most of the altitude exposure studies reported short-term effects (i.e., weeks). Repeated apneas increase Hct but this increase disappears within 10min after the last apnea [22,26].

The effects of repeated apneas on spleen and endogenous EPO may also constitute an alternative to using rhEPO or its analogues. In addition, comparison of resting Hb mass in elite BHDs and untrained subjects showed a 5% higher Hb mass in the BHDs, and the BHDs also showed a larger relative increase in Hb after three apneas (2.7%). The long-term effect of apnea training on Hb mass might be implicated in elite divers’ performances. Re- cently, it has been found that after a 3-month apnea training pro- gram, the forced expiratory volume in 1 s was higher (4.85 ± 0.78 vs. 4.94 ± 0.81 L, p < 0.05), with concomitant increases in the max- imal oxygen uptake, arterial oxygen saturation, and respiratory compensation point values during an incremental test [30].

In addition to increasing EPO and provoking splenic contraction, apnea training has been hypothesized to modify muscle glycolytic metabolism. An improvement in muscle buffer capacity [6,7,32] would reduce blood acidosis and post-apnea oxidative stress [6]. Delayed acidosis would also be advantageous for exercise perfor- mance. Finally, trained BHDs exhibit high lung volumes [15]. Ap- nea training might be interesting to improve respiratory muscle performance [15], thereby delaying the respiratory muscle fatigue during prolonged and maximal exercise.

Greater cerebral blood flow (CBF) increase was described during long apnea in elite BHDs than in controls and interpreted as a protection of the brain against the alteration of blood gas [33]. The CBF increase observed in BHDs could be the re- sult of an increased capillary density in the brain as has been de- scribed after a prolonged hypobaric hypoxia exposure [35]. These results suggest that apnea training per se provides hypoxic precon- ditioning, increasing hypoxemia and ischemia tolerance [33].

The physiological responses to apnea training exhibited by elite breath-hold divers may contribute to improving sports perfor- mance. These adaptations may be an effective alternative to hypo- baric or normobaric hypoxia to increase performance. Further experimental research of the apnea training effects on aerobic and/or anaerobic performance are needed to confirm this theory.

Ukjent sin avatar

Diaphragmatic Breathing Reduces Exercise-Induced Oxidative Stress

av

Om hvordan diafragmisk pust (med magen) øker antioksidantbeskyttelsen og restitusjonen ved å senke kortison og øke melatonin. Gjort på et 24t sykkerlritt hvor de som gjorde 1t pusteing før de sovnet fikk raskere restitusjon. Nevner direkte sammenheng mellom kortisol og melatonin. Og påstår at pusten bør implementeres i ethvert treningsregime som restitusjon.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139518/

Analysis of oxidative stress levels in people who meditate indicated that meditation correlates with lower oxidative stress levels, lower cortisol levels and higher melatonin levels. It is known that cortisol inhibits enzymes responsible for the antioxidant activity of cells and that melatonin is a strong antioxidant

Results demonstrate that relaxation induced by diaphragmatic breathing increases the antioxidant defense status in athletes after exhaustive exercise. These effects correlate with the concomitant decrease in cortisol and the increase in melatonin. The consequence is a lower level of oxidative stress, which suggests that an appropriate diaphragmatic breathing could protect athletes from long-term adverse effects of free radicals.

Stress is defined as a physiological reaction to undesired emotional or physical situations. Initially, stress induces an acute response (fight or flight) that is mediated by catecholamines. When stress becomes chronic and lasts for a long time, the stressed organism reacts with physiological alterations to adapt to the unfavorable conditions. This ACTH-mediated reaction affects the immune and neuroendocrine systems, and it is responsible for several diseases [1]. Numerous data support the hypothesis that the pathophysiology of chronic stress can be due, at least partially, to an increase in oxidative stress [2–4], which may also contributes to heart disease [5,6], rheumatoid arthritis [7,8], hypertension [9,10], Alzheimer’s disease [11,12], Parkinson’s disease [13], atherosclerosis [14] and, finally, aging [15].

High levels of glucocorticoids are known to decrease blood reduced glutathione (GSH) and erythrocyte superoxide dismutase (SOD) activity in rats [20]. Other enzymes are also involved, and NADPH oxidase, xanthine oxidase and uncoupled endothelial nitric oxide synthase are important sources of reactive oxygen species (ROS) in glucocorticoid-induced oxidative stress (see [9] for a review on this argument).

Hormonal reactions to stressors, in particular plasma cortisol levels, are lower in people who meditate than in people who do not [31–36], suggesting that it is possible to modulate the neuroendocrine system through neurological pathways. Analysis of oxidative stress levels in people who meditate indicated that transcendental meditation, Zen meditation and Yoga correlate with lower oxidative stress levels [37–43].

Melatonin could also be involved in the reduction of oxidative stress because increased levels of this hormone have been reported after meditation [44–46]. This neurohormone is considered a strong antioxidant and is used as a treatment for aging. Melatonin in fact, increases several intracellular enzymatic antioxidant enzymes, such as SOD and glutathione peroxidase (GSH-Px) [47,48], and induces the activity of γ-glutamylcysteine synthetase, thereby stimulating the production of the intracellular antioxidant GSH (49]. A number of studies have shown that melatonin is significantly better than the classic antioxidants in resisting free-radical-based molecular destruction. In these in vivostudies, melatonin was more effective than vitamin E, β-carotene [50–52] and vitamin C [53–55].

Although it has been established that a continuous and moderate physical activity reduces stress, intense and prolonged exercise is deleterious and needs a proper recovery procedure.

Plasma cortisol levels increase in response to intense and prolonged exercise [60,61]. Ponjee et al. [62] demonstrated that cortisol increased significantly in male athletes after they ran a marathon. In another study, plasma ACTH and cortisol were found elevated in highly trained runners and in sedentary subjects after intense treadmill exercise [63].

Most, if not all, meditation procedures involve diaphragmatic breathing (DB), which is the act of breathing deeply into the lungs by flexing the diaphragm rather than the rib cage. DB is relaxing and therapeutic, reduces stress and is a fundamental procedure of Pranayama Yoga, Zen, transcendental meditation and other meditation practices.

Athletes were monitored during a training session for a 24-h long contest. This type of race lasts for 24h, generally starting at 10:00am and ending at 10:00am the following day. Bikers ride as many kilometers as possible on a specific circuit trail in the 24-h period. Athletes are allowed to stop, to sleep, to rest and to eat as much food as they want to eat.

Subjects of the studied group were previously trained to relax by performing DB and concentrating on their breath. These athletes spent 1h (6:30–7:30pm) relaxing performing DB in a quiet place. The other eight subjects, representing the control group, spent the same time sitting in an equivalent quite place. The only activity allowed was reading magazines. Lighting levels were monitored throughout the experiment and did not exceed 15 lux, a level well below that known to influence melatonin secretion [73,74].

As expected, the exercise induced a strong oxidative stress in athletes (Figure 1).

BAP (Biological Antioxidant Potential) levels were determined at different times, before and after exercise. Athletes were divided in two equivalent groups of eight subjects. Subjects of the studied group spent 1h relaxing performing DB and concentrating on their breath in a quiet place. The other eight subjects, representing the control group, spent the same time sitting in an equivalent quite place. Since this test must be performed several hours after food ingestion, BAP levels were determined pre-exercise at 8:00am before breakfast, at 2:00am, and at 8:00am 24h post-exercise. Values shown are mean ± SD. *P < .05 DB versus control group. **P < .01 DB versus control group.

This study demonstrates that DB reduces the oxidative stress induced by exhaustive exercise. To our knowledge, this is the first study which explores the effect of DB on the stress caused by exhaustive physical activity.

The rationale is as follows (Figure 5)

  1. intense exercise increases cortisol production;
  2. a high plasmatic level of cortisol decreases body antioxidant defenses;
  3. a high plasmatic level of cortisol correlates with a high level of oxidative stress;
  4. DB reduces the production of cortisol;
  5. DB increases melatonin levels;
  6. melatonin is a strong antioxidant;
  7. DB increases the BAP and
  8. DB reduces oxidative stress.

If these results are confirmed in other intense physical activity programs, relaxation could be considered an effective practice to significantly contrast the free radical-mediated oxidative damage induced by intense exercise. Therefore, similar to the way that antioxidant supplementation has been integrated into athletic training programs, DB or other meditation techniques should be integrated into many sports as a method to improve performance and to accelerate recovery.

Hyperventilation, in fact, induces hyperoxia which is known to be related with oxidative stress [81,82]. The hyperventilation syndrome affects 15% of the population and occurs when breathing rates elevate to 21–23 bpm as a result of constricted non-DB. DB can treat hyperoxia and its consequences acting by two synergic ways: restoring the normal breath rhythm and reducing oxidative stress mainly through the increase in melatonin production which is known for its ability to reduce oxidative stress induced by exposure to hyperbaric hyperoxia [83].

Moreover, Orme-Johnson observed greatly reduced pathology levels in regular meditation practitioners [84,85]. A 5 years statistic of approximately 2000 regular participants demonstrated that Transcendental Meditation reduced benign and malignant tumors, heart disease, infectious diseases, mental disorders and diseases of the nervous system. Mourya et al. evidenced that slow-breathing exercises may influence autonomic functions reducing blood pressure in patients with essential hypertension [86]. Finally, there are also evidences that procedures which involve the control of the breathing can positively affect type 2 Diabetes [87], depression, pain [88], high glucose level and high cholesterol [89].

The role of melatonin must also be emphasized. Beyond its antioxidant properties, melatonin is involved in the regulation of the circadian sleep-wake rhythm and in the modulation of hormones and the immune system. Due to its wide medical implications, the increase in melatonin levels induced by DB suggests that this breath procedure deserves to be included in public health improvement programs.

DB increased the levels of melatonin in athletes, and this correlates with lower oxidative stress (ROMs), with lower cortisol levels and with the higher antioxidant status (BAP) in these athletes.

Tooley et al. [46] speculated that meditation-reduced hepatic blood flow [91] could raise the plasma levels of melatonin. Alternatively, since meditation increases plasma levels of noradrenaline [92] and urine levels of the metabolite 5HIAA [93], a possible direct action on the pineal gland could be hypothesized, as melatonin is synthesized in the pineal by serotonin under a noradrenaline stimulus [94]. More likely, we suspect that the increase in melatonin levels determined in our experiment can be mainly attributed to the reduced cortisol levels. Actually, a relationship between cortisol and melatonin rhythms has been observed [95], indicating that melatonin onset typically occurs during low cortisol secretion.

Overall, these data demonstrate that relaxation induced by DB increases the antioxidant defense status in athletes after exhaustive exercise. These effects correlate with the concomitant decrease in cortisol, which is known to negatively affect antioxidant defenses, and the increase in melatonin, a strong antioxidant. The consequence is a lower level of oxidative stress, which suggests that an appropriate recovery could protect athletes from long-term adverse effects of free radicals.