MUNI MED Adaptation Marie Nováková 1 Department of Physiology, Faculty of Medicine, Masaryk University ECOLOGICAL PHYSIOLOGY examines the influence of environment on living systems and their ability to adapt to changed conditions - ADAPTATION (Adaptation or Environmental Physiology) ADAPTATION STUDIES animal models human volunteers 2 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED REACTION (REGULATION): direct, immediate response of organism on environmental changes (seconds, minutes) ADAPTATION = a complex of biochemical, functional and structural changes in organism caused by long-lasting and repeated environmental changes (days, months, years) 3 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Adaptation = adjustment THM - Long-lasting structural and/or functional change - Leads to decrease in energetic demands needed for keeping homeostasis under new (changed) conditions - Functional / Evolutional advantage INDIVIDUAL s ADAPTATION ^GENETICALLY FIXED MUNI 4 Department of Physiology, Faculty of Medicine, Masaryk University . . ._ n ACCLIMATION Reaction of whole organism on change in one environmental factor ACCLIMATISATION Reaction of whole organism on change in several environmental factors 5 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED MECHANISMS OD ADAPTATION 1. Changed plasticity of nervous system • changes at molecular level in CNS • gene expression changes • regulation of number of neurites • changes in neuronal nets (cortical fields) 2) Changes of autonomous tonus (athletes) 3) Changes in organ structure (adaptation to exercise) 4) Temporary changes of skin colour (sunbathing) CIVILISATION DISEASES = maladaptation • gastric ulcer disease • hypertension •CAD • psychoses • neuroses 6 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED ADAPTATION MECHANISMS Example: adaptation of thermoregulation - Sweat glands hypertrophy - Increased subcutaneous adipose tissue - Metabolisms/energetic exchange - Sweating - Activity Adaptation Functional Morphological Mean body temperature -► Active system (controlling system) Effectors Passive system (controlled system) Mean body temperature t Endogenous t Exogenous heat (exercise) heat/cold 7 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Adaptation to extreme ambient temperature ADAPTATION TO COLD ADAPTATION INSULATIVE METABOLIC HYPOTHERMIC 18th century: surviving of shipwrecked sailors in cold water 1887: V. Priesnitz, S. Kneipp People suffer from low temperatures less in winter than in summer. 1. PROTECTION FROM HEAT LOSS (feather, vasoconstriction, increased amount of subcutaneous adipose tissue) 2. INCREASE OF HEAT PRODUCTION ( higher metabolic exchange) 3. DOWNWARDS SHIFT OF SET-POINT (opposite to fever, similar to hibernating animals) 9 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Acclimation. Human: as tropic animals (thermoneutral zone between 27° - 32°C) Seal, fog, seagull: arctic animals (thermoneutral zone between 20° - 40°C, thermoregulation starts below 20°C) In humans always all three mechanisms activated during adaptation. In adapted subject - 02 consumption decreases, HR not changed, BP increases (by 20 - 40mmHg), feeling of discomfort is lower (starts at lower temperature), downward shift of set-point (by 0.75°C) 10 Department of Physiology, Faculty of Medicine, Masaryk University COLD ADAPTATION PROCESS 30 - Mainly re-setting of set-point (new value) - Changed diet preferences (higher energy ii mass increase, slow increase in body fat pei - Cold diuresis (Na+ and K+ excretion) - up t( haemoconcentration, increased leucocytes c - Changed glycaemia: in non-adapted decre increases (no more stress) - Decreased skin threshold for pain (total hal sensitivity); stress analgesia during adaptatii - Decreased threshold for shivering Weight97kB Height 1,7 m J.Z. Department of Physiology, Faculty of Medicine, Masaryk University Adaptation to cold THM - Strategy: decrease heat loss (+ increase heat production) - Increased appetite - Increased subcutaneous adipose tissue - Re-setting of thermoregulatory centre - Decreased temperature for activation of shivering thermogenesis 12 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED ADAPTATION TO HEAT SWEAT PRODUCTION increases (may be even doubled) THREASHOLD FOR SWEATING decreases to lower temperatures (both core and periphery) DECREASED CONTENT OF ELECTROLYTES IN SWEAT PERCEPTION OF THIRST increases HIDROMEIOSIS (decreased production of sweat in humid hot climate, after the period of profuse sweating; decreases idle dropping of sweat) ADAPTATION OF TOLERANCE TO HEAT in inhabitants in the tropics, threshold for sweating is increased to higher body temperatures. ATTENTION must be paid to physical exercise !!! ^ I 13 Department of Physiology, Faculty of Medicine, Masaryk University M [ Adaptation to heat THM - Strategy: increase heat output + decrease heat production - Decreased appetite -Adaptation of sweating - Dependent on humidity; decreased sweat production, decreased ionic concentration - Re-setting of thermoregulatory centre - Increased temperature for sweating activation 14 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED ADAPTATION TO HIGH ALTITUDE PHOTO B. Sir Edmund Hillary and Sherpa Tenzing Norgay on Everest. This photograph shows Hillary and Norgay summiting Everest for the first time on May 1953. They used supplementary oxygen during their ascent. Source: © The Kobal Collection. 15 Department of Physiology, Faculty of Medicine, Masaryk University HIGH ALTITUDE ACCLIMATION (long-lasting stay) At least several weeks, fully developed after several months or years. CARDIOVASCULAR REACTIONS: HR and SV normalize, pulmonary arterioles constrict - pulmonary hypertension RESPIRATORY REACTIONS : minute ventilation stabilises (directly proportional to high altitude hypoxia), central chemoreceptors adapt INCREASED ERYTHROPOETIN SECRETION: polyglobulia, increased transport capacity of blood for 02, blood viscosity, density of mitochondria, and myoglobin content 17 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED 'ffl •--'-1- I I I I » I I I 11 12 13 14 11 1( 17 II 1» 20 21 22 23 11 12 13 14 It 1« 17 18 1> 20 21 22 23 Hemoglobin Concentration, gm/dL Hemoglobin Concentration, gm/dL 18 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED ACCLIMATISATION TO HIGH ALTITUDE - RECOMMENDATIONS After 3 days: A-B balance restores, Hb concentration increases After several weeks: exercising is possible GENETIC ADAPTATION IN ALPINE TRIBES • Bigger chest • Higher density of pulmonary capillary net • Bigger heart (EDV) • Higher cardiac output • Higher Hb concentration • Bigger bone marrow 19 Department of Physiology, Faculty of Medicine, Masaryk University Adaptation from birth??? MUNI ED Adaptation to physical exercise Static vs. Dynamic work Source: www.freepik.com - photo created by gpointstudio 20 Department of Physiology, Faculty of Medicine, Masaryk University Source: www.freepik.com - photo created by alexeyzhilkin MUNI MED Stimuli triggering adaptation -Overthreshold change of either external and/or internal environment - Long-lasting and/or repeated stimuli 21 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Adaptation to physical exercise THM -Skeletal muscle - Hypertrophy, neovascularisation - Cardiovascular system - Heart adaptation (concentric hypertrophy vs. athletes'heart) - Polyglobulia, resp. increased haemoglobin concentration - Adaptation of blood pressure and perfusion regulations (skeletal muscle, heart, kidney) - Respiratory system - Lungs growth (event, also chest growth), improved a-c diffusion - Metabolism 22 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Sedentary man Variable Prelraining Posttraining Runner Cardiovascular \\K at rest (beats • min') 71 MR max (beats • min') 185 SV rest (ml) 65 SVmax(ml) 120 Q rest (L • min ') 4.6 Q max (L • min ') 22.2 Heart volume (ml) 750 Blood volume (L) 4.7 Systolic BP rest (mmHg) 135 Systolic BP max (mmHg) 210 Diastolic BP rest (mmHg) 78 Diastolic BP max (mmHg) 82 Respiratory Vt rest (L • min ') 7 Vt rest (L • min') 110 TV rest (L) 0.5 TV max (L) 2.75 RR rest (breaths • min') 14 KR max (breaths • min') 40 Metabolic A^O, diff rest (ml • 100 ml1) 6.0 A-\iG2 diff max (ml • 100 ml') 14.5 VO, rest (ml • kg'• min') 3.5 VO, max (ml • kg 1 • min ') 40.5 Blood lac tate rest (mmol • L') 1.0 BUmxI lactate max (mmol • L') 7.5 59 183 80 140 4.7 25.6 820 5.1 130 205 76 80 6 135 0.5 3.0 12 45 6.0 15.0 3.5 49.8 1.0 8.5 36 174 125 200 4.5 32.5 1,200 6.0 120 210 65 65 6 195 0.5 3.9 12 50 6.0 16.0 3.5 76.5 1.0 9.0 23 Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED fr o 50 40 20 10 1 Trained Untrained Maximal untrained work capacity Oxygen uptake by lungs -Spiroergometry - Resting V02: -3.6 mL 02 / (min x kg) - V02max- objective index for aerobic power - untrained middle age person: 30 - 40 mL 02 / (min x kg) - elite endurance athletes: 80 - 90 mL 02 / (min x kg) - HF / COPD patients: 10 - 20 mL 02 / (min x kg) Adopted from: https://studentconsult.inkling.com/read/boron-medical-physiology-3e/chapter-60/figure-60-6 O, max Maximal trained work capacity 3.5 External power output watts \ kg body weight/ 24 Department of Physiology, Faculty of Medicine, Masaryk University MUNI ED Determinants of V 02 max 1. Uptake of 02 by the lungs - pulmonary ventilation 2. 02 delivery to the muscles - blood flow (pressure gradient - cardiac output x resistance) -hemoglobin concentration 3. Extraction of 02 from blood by muscle -p02 gradient: blood - mitochondria MUNI E D Athletes' heart -Adaptation to dynamic exercise -1 LVEDV -1 SV - (baroreflex) i HR - ~ CO at rest -1 cardiac reserve Source: https://asset5.beta.meta.org/discover/thematic-feed/83-athletic-heart-syndrome.jpg 26 Department of Physiology, Faculty of Medicine, Masaryk University MUNI ED Cardiac reserve in healthy and failing heart External power output [W/kg] 27 Marie Nováková, Department of Physiology, Faculty of Medicine, Masaryk University MUNI MED Volume Overload Aerobic exercise Pregnancy Early mitral regurgitation Athletes heart rfb-c I Hemodynamic Stress Eccentric pertrophy Pressure Overload Chronic hypertension Aortic Stenosis Aortic Coarctation I Hemodynamic Stress Concentric hypertrophy Compensated Hypertrophy r/h9 cm/s E/E' <6 S' >9 'f Stroke volume Electrical changes Sinus bradycardia Sinus arrhythmia First degree AV block Voltage LVH, and RVH Incomplete RBBB TWI in V1-V4 in black athletes Peripheral changes V ^ skeletal muscle fibres f capillary conductance ^ oxidative capacity "T^ mitochondrial enzymes "t* 02 Peak consumption Figure 2 Cardiovascular and peripheral adaptation to exercise in athletes. AV, atrioventricular; LV. left ventricular, LVH. left ventricular hypertrophy; LVWT, left ventricular wall thickness; RV. right ventricle; RVH. right ventricular hypertrophy; TWI. T-wave inversion. 31 Department of Physiology, Faculty of Medicine, Masaryk University EXERCISE AND HEART - GOOD, BAD, HARMFUL ??? Atrial Fibrillation Atrial Stretch 1* Vagal tone ^ Oxidative stress Shear forces ? Atherosclerosis Sinus Node disease AV block Ventricular arrhythmias ? Fibrosis ^Troponin Adverse cardiac remodelling ? Dilated cardiomyopathy ? Exercise induced ARVC Figure 6 Speculated mechanisms for the detrimental effects of exercise. ARVC. arrhythmogenic right ventricular cardiomyopathy; AV, atrioventricular; DCM, dilated cardiomyopathy. Department of Physiology, Faculty of Medicine, Masaryk University