Lecture 6-7 Exercise Physiology copy (2) PDF

DPT-413 Exercise Physiology course Exercise Is Physiology we Monira Aldhahi PT, MSc, DPT, PhD Department of Rehabilitation sciences Dr. Monira A...

DPT-413 Exercise Physiology course Exercise Is Physiology we Monira Aldhahi PT, MSc, DPT, PhD Department of Rehabilitation sciences Dr. Monira Aldhahi- -2024 All Rights Reserved Copyright  Learning outcome Identify the concepts of the total daily energy expenditure O Explain the effect of body weight on the energy cost of different forms of physical activity BM Engyane IA Dr. Monira Aldhahi- Copyright -2024 All Rights Reserved  TDEE stands for Total Daily Energy expenditure Threefactors determine the total daily energy expenditure (TDEE): 1. Resting metabolic rate 2 2. Thermogenic influence of consumed food 3 1 3.Energy expended during physical activity. Energy Expenditure During Physical Activity Eg  Basal Metabolic Rate A minimum energy requirement that sustains the body’s functions in the waking state. Oxygen consumption values for BMR usually range between 160 and 290 mL/min (0.8 to 1.43 kCal /min)  Resting Daily Energy Expenditure Can be predicted using model: include Body mass (BM), stature (S in centimeters), and age (A in years) Can successfully predict RDEE with sufficient accuracy using the following Equations for women and men are: Harris-Benedict Equation: kcal during 24 hrs Reference: Harris, J.A., Benedict, F.G. A biometric study of basal metabolism in man. Publ. No. 279. Washington, DC: Carnegie Institute. 1919. Activity 2 ( 5 min) 1470.765 Dr. Monira Aldhahi- -2024 All Rights Reserved Copyright  Estimation of Resting Daily Energy Expenditure Based on Fat-Free Body Mass (FFM) Following generalized equation, applicable to males and females over a wide range of body weights: For example : A male who weighs 90.9 kg at 21% body fat has an estimated FFM of 71.7 kg. What is the RDEE of this male? Dietary-induced thermogenesis mm Thermic effect of a meal has two components: m Obligatory Facultative thermogenesis thermogenesis digestion, peaks in 30–90 absorption minutes synthesis of depending on protein, fat, and size and content carbohydrate. of meal attributed to sympathetic nervous system activity Energy Expenditure During Physical Activity  Estimation of Caloric Expenditure Caloric Equivalent. The number of kilocalories produced per liter of oxygen consumed. Caloric Cost. Energy expenditure of an activity performed for a specified period of time. – It may be expressed as total calories (kcal), calories or kilojoules per minute (kcal·min −1 or kJ·min −1), or relative to body weight (kcal·kg −1 ·min −1 or kJ·kg−1·min −1). Pg. 201: CHAPTER 9 Human Energy Expenditure During Rest and Physical Activity by William D. McArdle William D. McArdle  see Estimation of Caloric Expenditure Table shows that carbohydrates are most efficient in the use of oxygen to provide energy, followed by fat, and finally by so protein—although the substrates do not really vary a great deal.  Estimation of Caloric Expenditure Factor determine the caloric cost of an activity: – amount of oxygen consumed – the caloric equivalent For all values of RER between 0.7 and 1.0. The caloric equivalent varies from 4.686 kcal·L−1 O2 at an RER of 0.7 to 5.047 kcal·L−1 O2 at an RER of 1.0. I  Estimation of Caloric Expenditure To compute the energy expenditure of activity (kcal·min−1 ) 1. finding the caloric equivalent for the RER 2. multiplying the oxygen cost by the caloric equivalent. Example derkztm.in Or g equate Erin RER Calomic em EEEEE.is ionaen  salute 4.936 2.15 Check Your Comprehension Determine the caloricor cost (in kilocalories and kilojoules) for minute 14 of Table 4.2. m RER 0.96 Calmicequalitat 4.998 Or 2.284min uh 0 Cubic Gut efn RER Calica 2 Or 4.998 2.28 Kcal min  The Metabolic Equivalent MET is an acronym derived from term Metabolic Equivalent. MET represents the average, seated, resting energy cost of an adult and is set at 3.5 mL·kg−1·min−1 of oxygen, or 1 kcal·kg−1·hr−1. exercise physiologists and physicians often use metabolic equivalent (MET) values. 3.5 ml kg min 1. 1 MET= 3.5 ml/kg/min MET 2. 1 MET= 1 kcal/kg/hr 1kcal kg her 3. 1L O2= 5kcal IM  The Metabolic Equivalent Resting metabolic rates (RMR) vary among individuals. A 2014 examination of 197 studies reporting resting metabolic rate found that the overall values were: – closer to 0.89 kcal·kg−1·hr−1 or 3 mL·kg−1·min−1 for men – 0.84 kcal·kg−1·hr−1 or 2.8 mL·kg−1·min−1 for women  Calculate MET levels Steps To calculate MET levels from measures of oxygen consumption : Divide the amount of oxygen utilized (in mL·kg−1·min−1) by 3.5. For example: an individual expends 29 mL·kg−1·min−1 of O2 on a task, what is his MET level? Answer:  29 mL·kg−1·min−1 ÷ 3.5 mL·kg−1·min−1 = 8.3 METs.  The Metabolic Equivalent To convert from MET to kcal·min−1, – it is necessary to know the individual’s BW – use the relationship 1 kcal·kg−1·hr−1 = 1 MET. For example: if the 8.3-MET activity is done by a female of average weight (68 kg), what is Nourah energy expenditure during that activity in kcal/min calculation is  Energy Expenditure of PA Consider an activity such as rowing continuously at 30 strokes per minute for 30 minutes. How can we determine the number of calories “burned” during the 30 minutes? If the amount of oxygen consumed averages 2.0 L/min  Answer Cal. Equivalent: 1 L of oxygen generates about 5 kCal of energy. Do that math (it gives 10kcal/min) Time: During each minute of rowing, then in 30 minutes the rower expends 300 kCal during the exercise.  The Metabolic Equivalent Alternately, the formula simplified as (METs × 3.5 mL·kg·min−1 × body weight in kg) ÷ 200 kcal·mL−1; where 200 kcal·mL−1 is 1,000 mL·L−1 ÷ 5 kcal·L−1 (Swain, 2010), may be used. The example then becomes  Gross Versus Net Energy Expenditure Energy expenditure can be expressed : 1- Gross energy expenditure or total values: include the resting energy requirement during the activity phase, 2- Net energy expenditure: reflects the energy cost of the activity that excludes resting metabolism over an equivalent time period  Field Estimates of gross Energy Expenditure during Exercise For an individual walking on a track at a 20 min·mi−1 pace (3 mi·hr−1), which is a velocity of 80.4 m·min −1 (3 mi·hr−1 × 26.8 m·min−1·mi·hr−1), the calculation is as follows:  Activity 2 ( 5 min) Dr. Monira Aldhahi- -2023 All Rights Reserved Copyright  Problem solving Q If a 65 y/o, 84 kg female walks 2.5 mi/hr:15min at 3 METS, how many kilocalories does she expend ? 1. Convert MET to kcal/kg/hr 2. Convert kcal/kg/hr to kcal/kg/min 3. Multiply by kg 4. Multiply by time of exercise  If a 65 y/o, 84 kg female walks 2.5 mi/hr:15min at 3 METS, how many kilocalories does she expend ? 3 MET= 3 kcal * 84kg/ 60 = 4.2 kcal/min Energy expend in1:15 min = 4.2 * 75 =315 kcal  Convert MET TO Kcal/min 1 MET. For example, if a person who weighs 70 kg bicycles at 10 mph, which is listed as a 10-MET activity, What is the corresponding kCal expenditure ? 11.6666666  How to Calculate TDEE To find out the total daily energy expenditure begins with: 1. calculating your BMR (kcal for 24hr). – It contributes the biggest portion of your TDEE. 2. multiply BMR by your activity factors : Sedentary (little to no exercise + work a desk job) = 1.2 Lightly Active (light exercise 1-3 days / week) = 1.375 Moderately Active (moderate exercise 3-5 days / week) = 1.55 Very Active (heavy exercise 6-7 days / week) = 1.725 Extremely Active (very heavy exercise, hard labor job, training 2x / day) = 1.9 Tappy, L. (1996). Thermic effect of food and sympathetic nervous system activity in humans. Reproduction, Nutrition, Development, 36(4), 391397. http://www.ncbi.nlm.nih.gov/pubmed/8878356/  Activity 3 ( 5 min) Dr. Monira Aldhahi- -2023 All Rights Reserved Copyright  Problem Solving Q John is a 30-year-old male who is 6 feet tall and weighs 185 lbs. Age: 30 Height: 6’0” = 72 inches = 182.88cm (to convert inches to centimeters, multiply your height in inches by 2.54) Weight: 185 lbs = 84.09kg (to convert pounds to kilograms, divide your weight in pounds by 2.2) What is John TDEE to maintain his current weight?  Activity a 30-year-old male named John who is 6 feet tall and weighs 185 lbs. he is moderately physical active Age: 30 Height: 6’0” = 72 inches = 182.88cm (to convert inches to centimeters, multiply your height in inches by 2.54) Weight: 185 lbs = 84.09kg (to convert pounds to kilograms, divide your weight in pounds by 2.2) What is John TDEE? Using the Harris-Benedict Equation for men, and plugging the above numbers into the equation gives you: – BMR = 66 + (13.7 x 84.09) + (5 x 182.88) – (6.8 x 30) – BMR = 66 + 1152.03 + 914.4 – 204 – BMR = 1928.43 calculate John’s approximate TDEE, multiply his BMR by 1.55. This gives us: – TDEE = 1.55 x BMR – TDEE = 1.55 x 1928.43 – TDEE = 2989.07 – So, our example guy John needs to consume about 2990 calories each day just to maintain his current weight. Tappy, L. (1996). Thermic effect of food and sympathetic nervous system activity in humans. Reproduction, Nutrition, Development, 36(4), 391–397. http://www.ncbi.nlm.nih.gov/pubmed/8878356/  Factors Affect Energy Expenditure Physical Activity Climate Dietary-induced thermogenesis – 1-obligatory thermogenesis – 2- facultative thermogenesis Body size Pregnancy Pg 198-200  Pregnancy Pregnancy does not compromise the absolute value for aerobic capacity. As pregnancy progress: mmmm 1. maternal body weight add⇢ ↓ the economy of movement. 2. the later stages of pregnancy ⇢ ↑ pulmonary ventilation at a given submaximal exercise intensity. 3. The hormone progesterone ⇢ ↑ the sensitivity of the respiratory center to CO2⇢ ↑ maternal hyperventilation  Cardiovascular Responses to Exercise feedlot Wilmore, J. H., Costill, D. L., & Kenney, W. L. (2008). Physiology of sport and exercise. Champaign, IL: Human Kinetics. Plowman, S. A., & Smith, D. L. (1997). Exercise physiology for health, fitness, and performance. Boston: Allyn & Bacon. Ch 13  The Circulatory System 1. To transport oxygen and nutrients to the cells of the body and to transport carbon dioxide and waste products from the cells 2. To regulate body temperature, pH levels, and fluid balance 3. To protect the body from blood loss and infection  Cardiovascular Responses: Integration of Exercise Response Cardiovascular responses to exercise complex, fast, and finely tuned First priority =>maintenance of blood pressure –Blood flow can be maintained only as long as BP remains stable The Circulatory System Two major adjustments of blood flow during exercise Increased cardiac output Redistribution of blood flow  Mechanisms regulate and altered cardiovascular response during exercise training mediated by external factors such as circulating Mechanism catecholamines and nervous input to the heart (extrinsic regulation) mediated by the heart itself (intrinsic regulation).  Mechanisms regulate and altered cardiovascular response during exercise training intrinsic regulation 1- increase in atrial filling=> the stretching directly related to changes in muscle fiber of the atria stimulate length(Frank-Starling Law of the Heart) its receptors (A,B) to other intrinsic, length independent causes (termed homeometric autoregulation). 2- S A node (intrinsic automaticity 3- Rate Induced Regulation  Extrinsic Regulation of Cardiorespiratory Responses 1. Central Command feedforward Stimulates cardiorespiratory control center » Higher brain centers » Coactivates motor and cardiovascular centers  Extrinsic Regulation of Cardiorespiratory Responses 2- Baroreflex:  Extrinsic Regulation of Cardiorespiratory Responses 3. Exercise Pressor Reflex  Factors that Regulate Cardiac Output Book by Power. Ch 9: Circulatory Responses to Exercise  Activity 4 ( 10 min) so Dr. Monira Aldhahi- -2022 All Rights Reserved Copyright  Answer the Following Questions What does it mean by steady state exercise? Calculate TPR for an individual doing short term light to moderate submaximal aerobic exercise by using the following information – MAP= 110 mmgh – Q-15L/min  Cardiovascular Responses: Cardiac Output (Q) Q = HR x SV  With  intensity, plateaus near VO2max Normal values – Resting Q ~5 L/min – Untrained Qmax ~20 L/min – Trained Qmax 40 L/min Qmax a function of body size and aerobic fitness  Cardiovascular Responses: Heart Rate (HR) Changes in heart rate and blood pressure Depend on: Type, intensity, and duration of exercise Environmental condition Emotional influence  Cardiovascular Responses: Resting Heart Rate (RHR) Anticipatory response: HR  above RHR just before start of exercise –Norepinephrine, epinephrine  Cardiovascular Responses: Heart Rate During Exercise Directly proportional to Maximum HR (HRmax): exercise intensity highest HR achieved in all- out effort to volitional fatigue Highly reproducible Declines slightly with age Better estimated HRmax = 208 – (0.7 x age in years)  Cardiovascular Responses: Heart Rate During Exercise Steady-state HR: point of plateau, optimal HR for meeting circulatory demands at a given submaximal intensity – If intensity , so does steady-state HR – Adjustment to new intensity takes 2 to 3 min Steady-state HR basis for simple exercise tests that estimate aerobic fitness and HRmax  Lecture 7 Wilmore, J. H., Costill, D. L., & Kenney, W. L. (2008). Physiology of sport and exercise. Champaign, IL: Human Kinetics. Ch 8  Which Clients have a High Fitness Level? Illustrates results from a submaximal graded exercise test performed on a cycle ergometer by two different individuals of the same age.  Cardiovascular Responses: Regulation of Stroke Volume  Preload: Volume of blood in the ventricles at the end of diastole (“preload”)  end-diastolic ventricular stretch –  Stretch (i.e.,  EDV)   contraction strength – Frank-Starling mechanism  Contractility: inherent ventricle property –  Norepinephrine or epinephrine   contractility – Independent of EDV ( ejection fraction instead)  Afterload: aortic resistance (R)  Pressure the heart must pump against to eject blood (“afterload”)  End-Diastolic Volume Frank-Starling mechanism Greater EDV results in a more forceful contraction Due to stretch of ventricles Dependent on venous return Venous return increased by: – Venoconstriction via SNS – Skeletal muscle pump – Respiratory pressure  Cardiovascular Responses: Stroke Volume (SV)  With  intensity up to 40 to 60% VO2max – Beyond this, SV plateaus to exhaustion – Possible exception: elite endurance athletes SV during maximal exercise ≈ double standing SV SV during maximal exercise only slightly higher than supine SV – Supine SV much higher versus standing – Supine EDV > standing EDV  Stroke Volume (SV) Response to Maximal exercise intensity A subject exercises on a treadmill at increasing intensities. Stroke volume is plotted as a function of percent VO2max. The SV increases with increasing intensity up to approximately 40% to 60% of VO2max, Wilmore, J. H., Costill, D. L., & Kenney, W. L. (2008). Physiology of sport and exercise. Champaign, IL: Human Kinetics.  Cardiac Output and Stroke Volume: Untrained Versus Trained Versus Elite  Resistance Depends upon: Length of the vessel Viscosity of the blood Radius of the vessel Length x viscosity Resistance = Radius4  Cardiovascular Responses: Blood Pressure During endurance exercise, mean arterial pressure (MAP) increases – Systolic BP  in proportional to exercise intensity – Diastolic BP does not change submaximal dynamic exercise or slight increase (at max exercise) MAP = Q x total peripheral resistance (TPR) –Q  – If Steady state prolonged = decrease SBP & TPR – Muscle vasodilation versus sympatholysis  Blood pressure response during exercise Illustrates a typical blood pressure response in a healthy subject during leg and arm cycling exercise with increasing exercise intensities. upper body exercise causes > blood pressure response than leg exercise =attributable to the smaller exercising muscle mass of the upper body + an increased energy demand.  Cardiovascular Responses to Aerobic Exercise Short-Term, Light to Moderate Submaximal Aerobic Exercise Long-Term, Moderate to Heavy Submaximal Aerobic Exercise Incremental Aerobic Exercise to Maximum Upper-Body versus Lower-Body Aerobic Exercise Cardiovascular variables HR Rate pressure SV product BP SBP Q DBP TPR  Pressure rate product (RPP) an Index of Myocardial Oxygen Consumption Pressure rate product (RPP) is used in cardiology and exercise physiology to determine the myocardial workload. Rate Pressure Product (RPP) = Heart Rate (HR) * Systolic Blood Pressure (SBP)  Cardiovascular Responses to Aerobic Exercise Aerobic exercise requires more energy⇢ O2 Oxygen required depends primarily on the intensity of the activity and secondarily on its duration. 1. Short-term (5–10 minutes), light (30–49% maximal oxygen consumption, VO2max) to moderate (50–74% VO2max) submaximal exercise 2. Long-term (>30 minutes), moderate to heavy (60–85% VO2max) submaximal exercise 3. Incremental exercise to maximum (increasing from ~30 to 100% VO2max). Short-Term, Light to Moderate Submaximal Aerobic Exercise Systemic vascular resistance (SVR) refers to the resistance to blood flow offered by all of the systemic vasculature, excluding the pulmonary vasculature. This is sometimes referred as total peripheral resistance (TPR). SVR is determined by factors that influence vascular resistance in individual vascular beds Long-Term, Moderate to Heavy Submaximal Aerobic Exercise Blood volume decreases during submaximal aerobic exercise. The largest decrease occurs during the first 5 minutes of exercise, and then plasma volume stabilizes. This rapid decrease in plasma volume suggests that it is fluid shifts, rather than fluid loss, that account for the initial decrease. The magnitude of the decrease in plasma volume depends on the intensity of exercise, environment factors and individual hydration status. Long-Term, Moderate to Heavy Submaximal Aerobic Exercise cardiovascular drift is associated with: 1- rising body temperature 2- combination of exercise and heat stress produces competing regulatory demands—specifically, competition between skin and muscle for large fractions of QT.  Read the article ( Ref. ch 12- pg 361 by Plowman) Hamilton, M. T., J. G. Alonso, S. J. Montain, & E. F. Coyle: Fluid replacement and glucose infusion during exercise prevents cardiovascular drift. Journal of Applied Physiology. 71:871– 877 (1991).  Importance of the fluid ingestion Data from a study in which subjects cycled for 2 hr with and without fluid replacement (Hamilton, et al., 1991). When subjects consumed enough water, cardiac output remained nearly constant Cardiac output was maintained in the fluid replacement trial because stroke volume did not drift downward (Figure b). Heart rate was significantly lower when fluid replacement occurred (Figure c). Incremental Aerobic Exercise to Maximum  Intermittent Exercise Recovery of heart rate and blood pressure between bouts depend on: – Fitness level – Temperature and humidity – Duration and intensity of exercise. Upper-Body versus Lower-Body Aerobic Exercise  Arm versus Leg Exercise At the same oxygen uptake arm work results in higher: – Heart rate Due to higher sympathetic stimulation – Blood pressure Due to vasoconstriction of large inactive muscle mass. Figure: Circulatory responses to prolonged, moderately intense exercise in the upright posture in a thermoneutral 20 °C environment  Reference 1.Exercise Physiology for Health, Fitness, and Performance by Sharon A.Plowman and Dr. Denise L. Smith PhD 3rd ed (Ch. 4th , pp. 105-108) -(Ch12) 1.William D. McArdle, Frank I. Katch, Victor L. Katch. Exercise Physiology: Nutrition, Energy, and Human Performance. ch 8 & 9 Physiology: Theory and Application to Fitness and Performance by Scott Powers and Edward Howley (Ch2) pg. 67- 69; Pg. 83-86