Kin 310 Exercise/Work Physiology

1. Kin 310Exercise/Work Physiology • Office hours - HC 2910 (lab) • F 10:30-11:20 • or by appointment (ryand@sfu.ca) • class email list • announcements, questions and responses • inform me of a preferred email account • class notes will be posted on the web site in power point each week • can be printed up to six per page • lecture schedule along with reading assignment on web site • www.sfu.ca/~ryand/kin310.htm

2. Energy for Exercise and Work • Brooks p1-10; ch 4 • Astrand ch. 17 p 503-540 • Mcardle, Katch and Katch Appendix D • Outline • Introduction to Exercise Physiology • Course overview • Energy, work and power • Calorimetry and the estimation of metabolic rate • Assessment of workload • Relative VO2, HR, Hormonal response • Energy expenditure over workday • Energy systems, work rest ratio

3. Exercise Physiology • Physiological responses to exercise depend on • Intensity, Duration, Frequency, Environmental circumstances, Diet, Health, Physiological status • Exercise requires the conversion of chemical into mechanical energy • Principles of bioenergetics control and limit performance • Acquisition and utilization of energy and the role of organ systems in supporting these processes will be discussed • Understanding short (acute) and long term (chronic) effects of exercise on the human machine is important in exercise science and health

4. Rate Limiting Factor • What limits performances? • Proper analysis of a sport or work situation is important to identify; • Pathways and metabolic sequences that are used • The factors which turn the rate of these pathways up or down • The steps that are limiting or slow • All of this is required to understanding function, pathophysiology (disease) and to concentrate efforts when training to improve performance • Eg. VO2 fig 1-5 • Limited by cardiovascular system • Widely used criterion of physical fitness

5. Performance • Stress and Response • With appropriate stimuli, physiological systems respond with increased functional capacity (training) • Overload but not overtrain • Seyle - General Adaptation Syndrome (GAS) • Alarm Reaction (shock) • Resistance Development (adaptation) • Exhaustion (staleness) • Principles of Fitness • Overload • Specificity • Reversibility • Individuality

6. Course Overview • Discussion of the physiological basis of exercise and work • Evaluating Energy and Workload • Cardiovascular and respiratory compensations and capacities • Limitations and adaptations to training • Cellular bioenergetics • Providing ATP to meet demand and recovery • Fatigue - inability to sustain activity level • description of fatigue in the CNS, the neuromuscular junction and the muscle cell • Molecular level adaptation • activity changes the cellular environment - stimulating adaptation to better meet demand • Work place / sport analysis and assessment of worker /athlete capacity • Strength evaluation variables • Ageing - change in physiological capacities - impacts of disease and activity level • Exercise and the Environment • Heat and barometric pressure can create additional demands on physiological systems

7. Energy • Energy - capacity or ability to perform work - joules, calories • Work - application of a force through a distance - joules, calories, Kg*m • Biological work - transport, mechanical and chemical work • Power - amount work performed over a specific time (workrate) - Joules/s; kg*m *min-1 • Transformation of energy - forms of energy can be converted from one form to another • chemical energy in food is transformed into mechanical energy of movement or other biological work • Biological energy cycle

8. Metabolism • Metabolism - the total of processes occurring ina living organism • Because heat is produced by these processes, the ‘metabolic rate’ can be measured by the rate of heat production • Ultimately, all metabolic processes depend on biological oxidation • Measuring O2 consumption is a good estimate of heat production, or metabolic rate • Energy Transduction • Photosynthesis • cell respiration (*not ventilation*) • cell work

9. Calorimetry • Calorie - heat energy required to raise one gram of water one degree Celcius • Calorimetry - procedure to measure metabolic rate • Direct Calorimetry - measurement of heat - very difficult • Indirect Calorimetry - measurement of Oxygen use - valid and reliable • Fig 4-8 Atwater and Rosa • Determined heat production, oxygen consumption and carbon dioxide production simultaneously • Established relationship between direct and indirect methods • Bomb calorimeter - energy value of food when ignited - fig 4-9 • Appendix D - Mcardle, Katch and Katch (on resreves)

10. Respiratory Quotient • Table 4.1 - energy per unit oxygen different - carbohydrates 6.4 % higher • Respiratory Quotient - Ratio of CO2 produced to O2 consumed • Value obtained gives an indication of the type of fuel being used in muscle • Pure Glucose RQ = 1.00 • Pure Fat RQ = .70 • Mixed fuel will provide intermediate value depending on mix • Fig 4.10 marathon RQ values • R value - an estimate of RQ that is measured at the mouth • Must consider non-metabolic sources of CO2 - Fig 4-14

11. Measurement of Metabolic Response • Evaluation provides info about absolute and relative intensity of exercise bout (fig 10.1a) • absolute VO2 (L/min or ml/Kg/min) • % of VO2 max • % of HR max • multiples of Metabolic Rate (MET’s) • 1kcal/Kg/hour at rest; 3.5mlO2/kg/min • determination of metabolic response allows estimation of • Total energy cost • Nutritional requirements • Efficiency calculations • Estimation of workload indicates metabolic system utilization, and the potential for fatigue

12. Work Load Assessment • Assessment of work load in relation to work capacity • variability in capacity • variability in response • expression of workload by absolute VO2 alone is almost meaningless • Need work load as % of individual max • Assessment requires the determination of ; • individual VO2 max • VO2 requirement of imposed load • assessment of muscle groups being utilized, and the % of their maximum strength -to determine fatigue onset

13. Assessment • Maximal aerobic power • direct - VO2 max test • estimation - predictive tests • Assessment of Workload • measure O2 uptake during work • Fig 17-2 O2 uptake vs bike/work • portable devices, rapid analysis of VCO2 and VO2 - large data base • field studies - collect expired air • Douglas bag • or - use flow meter to determine volume of air, and take samples of air for content analysis • Fig 17-3 commercial fisherman • subjects often affected - test atypical • Eg. Breathing through mouth not nose

14. Indirect assessment • Recall linear relationships between HR and VO2, VO2 and work rate • HR may be used to estimate workload - on individual basis • same muscle groups environmental temperature, and emotional stress • Continuously recorded HR • provides general picture of overall activity level during entire day • along with time activity studies collected by observers • possible to separate different activities with respect to HR • Fig 17-5 - fisherman

15. Comparison studies • Fig 17-6 - strong day - day consistency • Computer analysis of HR data gives; • mean values, peak values, distribution and HR variability • Fig 17-8 comparison of direct vs indirect measurement +/- 15 % • HR is good estimate of workload when work uses large muscle groups • Fig 17-9 arm vs leg work • HR is higher in arm work than leg work for the same work load. • O2 uptake for work load must be expressed as % max of individual • indicates relative degree of exertion • HR reserve (HR max - HR rest) • Circulatory strain is best expressed as a percentage of an individuals HR reserve

16. Stress of Work • The total stress imposed on the organism by a given work situation (physical or psychological) is generally reflected by nervous and hormonal stimulation • Proportional to the degree of stress • Nervous Response • Inc sympathetic tone - inc HR • influence linear relationship • Eg HR vs workload • Hormonal response • total stress reflected by sympathetic response • Measure ep and/or nor ep with urinary excretion or blood samples • Fig 17-16, 17-17 - Catecholamines - inc with standing, cold and emotion • Also inc with duration and severity of muscular exertion

17. Energy Expenditure • Need to establish practical limits for physical work loads • Type of work and work/rest cycles are important • Large individual differences in physical work capacity • 30 - 40% VO2 max for 8 hour day • 40 % of max strength in repetitive muscular work; • rest:work ratio of ; 2:1 • physiological and psychological responses influenced by • individual max aerobic power • size of muscle being engaged • working position • Static or dynamic work • intermittent vs continuous activity • environmental conditions

18. Daily Energy Expenditure • Important for • calculation of energy needs • determine physical activity of groups • role of physical activity in health • Methodology • 24 hr recorded HR • time activity data • assessment of daily energy intake to maintain body weight • all fairly accurate +/- 15% • show large individual variability • 1300-5000 kcal /day • Table 17-1, 17-2

19. Energy expenditure • O2 uptake and HR - Table 17.1 • Important for ; • Calculation of energy needs • Determine physical activity of groups • Role of physical activity in health • Methodology All fairly accurate +/- 15% • 24 hr recorded HR ; Time activity data (video analysis) • Assessment of daily energy intake to maintain body weight • Wide individual variability in energy output - Table 17-1,2 • Occupation • Leisure activity / Physical activity • Environmental temp • Daily rate 1300 - 5000 kcal • Reg active male 2900 kcal/day • Reg active female 2100 kcal/day

20. Energy Expenditures • Work expenditures • Most light work < 5 kcal /min • Some physical jobs 7.5 - 10.5 kcal/min • Permissible limits for daily work 2000-2500 kcal • Limits are difficult due to individual differences in work capacity or fitness • Individuals will usually self regulate the rest pauses • Peak load is more important than mean energy expenditure • You can attain a higher 8 hour energy expenditure if the work is consistent and does not have peak loads • Basal Metabolic rate (BMR) - rate of energy metabolism in a resting individual 14-18 hours after eating

21. Energy Expenditure • Recreational activities • McArdle, Katch and Katch • Appendix C (on reserves) • Different activities have different energy expenditures • Cycling race 13 kcal/min • Golf 6 kcal/min • Skiing uphill fast 21 kcal/min • Swimming -fast 13 kcal/min • Running 5:30 mile 22 kcal/min • Individuals do activities at different intensities • Must take body weight into account