Sports nutrition Pennington Biomedical Research Center Nutrition for

Sports nutrition Pennington Biomedical Research Center Nutrition for Health Professionals

Benefits of exercise People who are physically active on a regular basis have a reduced risk of hypertension, heart disease, diabetes, osteoporosis, depression, anxiety, sleep problems, and frailty. Exercise reduces the risk of gaining weight and becoming obese, reduces the risk for stroke and, now we have some very good data that indicates that certain types of cancer may be reduced by exercise. PBRC 2009 2

Exercise has Specific Benefits on: Cardiovascular health – Increases heart strength and overall cardiovascular function, which decreases chance of developing coronary heart disease and stroke – Helps maintain healthy blood pressure – Can increase HDL-cholesterol and lower LDL-cholesterol and triglycerides in the blood Obesity – Helps maintain lean tissue and promote loss of fat tissue – Assists in better control of appetite & increases energy expenditure – Helps prevent or reverse development of diseases associated with obesity including type 2 DM, HTN, and CVD (even if one can’t attain a more healthy weight) PBRC 2009 3

Exercise has Specific Benefits on: Muscular health – Contributes to building and maintaining muscle mass and muscle tone Diabetes – Increases glucose uptake by muscle tissue cells independent of insulin action – Contributes to energy balance, which decreases risk of type 2 diabetes and related complications Osteoporosis – Helps strengthen bones and contributes to joint health PBRC 2009 4

Exercise has Specific Benefits on: Infections – Reduces susceptibility to respiratory and other infections by enhancing various functions of the immune system Cancer – Reduces risk of colon cancer, and likely breast cancer Gastrointestinal health – Improves peristaltic function and colonic mass movements – Lessens risk for gallstones and related gallbladder disease PBRC 2009 5

Exercise has Specific Benefits on: Fewer Injuries (from falls) – Contributes to balance and agility, especially in older adulthood Psychological health – Reduces depression, anxiety, and mental stress, while enhancing a sense of well-being and self- image, and improving sleep patterns PBRC 2009 6

Recommendations: Experts recommend that, to help yourself stay with an exercise program, you should: should – Start slowly – Vary your workouts; make it fun – Workout with friends and others – Set specific attainable goals and monitor progress – Set aside a specific time each day for exercise; build it into your routine, but make it convenient – Reward yourself for being successful in keeping up with your goals – Don’t worry about occasional setbacks; focus on the long-term benefits to your health PBRC 2009 7

Diet There is nothing unique about the optimal diet for a person who is in an exercise program. One important aspect about physical activity and its interaction with nutrition is that, when people become physically active, research shows that they will spontaneously eat more. Over time, exercised individuals will be able to maintain their energy balance, reducing weight gains that occur with aging. PBRC 2009 8

Energy Needs Because of the increased energy demands of physical activity, individuals need to eat a little bit more in their diet to maintain their body weight. This, in turn, means that they are spontaneously getting more of the other types of nutrients in their diet: protein, vitamins, and minerals. PBRC 2009 9

Supplements An exercise program combined with supplemental protein or micronutrients has no great benefits over exercise alone as far as increasing aerobic capacity, muscle strength, and function. To date, there is little added benefit from the nutritional manipulation on performance. PBRC 2009 10

Protein: Supplementation There is no evidence whatsoever that increasing protein over and above what people normally take in their diet will optimize the gain in muscle mass with exercise or optimize performance. Most Americans well exceed the RDA for protein each day anyways. So, for healthy men and women, adding protein supplements is not going to help at all. PBRC 2009 11

Protein: Athletes Typical protein needs for athletes range from 1. 2 to 1. 6 g/kg body weight. For endurance athletes, about 10% of energy comes from protein and these individuals should aim for the higher value. Untrained subjects undergoing endurance training increase their protein need to about 1. 0 to 1. 2 g/kg/d, well above the RDA of 0. 8 g/kg body weight. PBRC 2009 12

Protein: Body building In the initial stages of body building when a lot of new tissue is being built, intake should be around 1. 8 -2. 0 g/kg body weight. This is probably due to the fact that resistance exercise seems to exert an anabolic effect and allows for better protein utilization. Once the desired muscle mass is achieved, protein intake need not exceed twice that of the RDA ( > PBRC 2009 1. 6 g/kg). 13

Protein: Older Adults A subset of about 20 to 25% of older men and women may not get the RDA for protein. For them (and the very frail, or with denture problems and poor food intake) increased protein intake is recommended when they are starting an exercise program. Protein should be from food sources, not from supplements. Milk shakes and other dairybased foods can greatly help. PBRC 2009 14

Protein: Toxicity There could be a toxicity risk when people start consuming too much protein (over 2. 0 g/kg/d). An excessive load of protein represents a stressful stimulus for the kidney. This is even more of a concern as we get older, when the kidneys activities decrease. Very high protein diets will result in overworking the filtration system of the kidneys. PBRC 2009 15

AA: Supplements Amino acid supplements are widely used by athletes. These supplements are not digested and absorbed in the body as readily as amino acids coming from food sources. Moreover, amino acid supplements tend to cause an imbalance of the amino acids already present in the body. PBRC 2009 16

Fuels for muscle cells Source/System ATP When in Use Examples of an Exercise At all times All types All exercises initially; extreme exercise thereafter Shotput, jumping Carbohydrate (anaerobic) High-intensity exercise, especially lasting 30 seconds to 2 minutes 200 -yard (20 meter) sprint Carbohydrate (aerobic) Exercise lasting 2 minutes to 4 -5 hours; the Basketball, swimming, higher the intensity, the greater the use jogging Phosphocreatine (PCr) Fat (aerobic) Exercise lasting more than a few minutes; greater amounts are used at lower exercise intensities Long-distance running, long-distance cycling; much of the fuel used in a brisk walk is fat Protein (aerobic) Low quantity during all exercise; moderate quantity in endurance exercise, especially when carbohydrate fuel is lacking Long-distance running

Phosphocreatine (PCr) During periods of relaxation, muscles synthesize PCr from ATP and creatine and then store this in small amounts. As soon as ADP, from the breakdown of ATP, begins to accumulate in a contracting muscle, an enzyme is activated that transfers a high-energy Pi from PCr to ADP, thus reforming ATP. PCr + ADP Cr + ATP Advantage of PCr: PCr It can be activated instantly and can replenish ATP at rates fast enough to meet the energy demands of the fastest and most powerful sports events. Disadvantage of PCr: PCr Not enough is made and stored in the muscle to sustain a high rate of ATP resupply for more than a few minutes. PBRC 2009 18

Anaerobic Pathway Carbohydrate The anaerobic pathway has three major disadvantages: – It can’t sustain ATP production for long – Only about 5% of the energy available from glucose is released during glycolysis – The rapid accumulation of lactate greatly increases the acidity of muscle cells Because high acidity inhibits the activity of key enzymes in glycolysis, anaerobic ATP production soon slows and fatigue sets in. PBRC 2009 19

Aerobic Pathway Carbohydrate If there is plenty of oxygen available in muscles (aerobic state) and the physical activity is of moderate to low intensity (jogging or distance swimming), then the bulk of pyruvate produced by glycolysis is shuttled to the mitochondria and further metabolized into carbon dioxide and water in a series of reactions. Although the aerobic pathway supplies ATP more slowly than does the anaerobic pathway, it releases more energy. In addition, ATP production via the aerobic pathway can be sustained for hours. PBRC 2009 20

Fat Main fuel for prolonged low-intensity exercise Factors that increase the rate at which muscles use fatty acids for energy. – How much the particular muscle is trained Muscles that are highly trained contain more, larger mitochondria when compared to similar untrained muscles. – The concentration of fatty acids released from adipose stores into the bloodstream If more is present, then more will be used. – Length of exercise As exercise becomes increasingly prolonged, fat use predominates (especially if exercise remains at a low->moderate aerobic rate). PBRC 2009 21

Protein Minor fuel source, primarily for endurance exercise Although amino acids derived from protein are used to fuel muscles, their contribution is relatively small when compared with that of carbohydrate and fat. Only about 5% of the body’s general energy needs are supplied by proteins. However, proteins can contribute significantly to energy needs in endurance exercise, perhaps as much as 10 -15%, especially as glycogen stores in the muscle are exhausted. PBRC 2009 22

Fuel Use and Sources A 100 -meter sprint is powered by stored ATP, creatine phosphate, and glycolysis of muscle glycogen producing lactic acid. A 1000 -meter run is powered at first by ATP, creatine phosphate and glycolysis and also some fat oxidation. Marathon: ATP generated equally from glycogen and fatty acids are used as fuel for marathons. PBRC 2009 23

Velocity versus Fuel ATP More Carbohydrate More Fat PBRC 2009 24

Energy Needs The daily energy needs of an athlete depend on his/her activity factor. A high level of sustained activity can double the daily energy required for BMR and activity. Weight maintenance indicates adequate caloric intake. PBRC 2009 25

Energy Needs Calories are an important factor but not one to worry very much over because normal appetite regulation will enable individuals to adjust their intake, depending on what their energy expenditure dictates. If a person starts an exercise program, his/her appetite will generally increase to meet the body's extra needs and, in this way, the individual will be able to maintain weight. PBRC 2009 26

Vitamins and Minerals Higher energy intake generally assures greater intake of vitamins and minerals if sensible meals are consumed. Long distance and marathon runners may require iron supplementation due to breakdown of red blood cells during prolonged running events. PBRC 2009 27

Carbohydrate Loading Days 1 2 3 4 5 6 Exercise Time (minutes) Rest 20 20 40 40 60 Carbohydrate (g) 600 450 450 600

“Appropriate” Activities for Carbohydrate Loading… Marathons Long-distance swimming Cross-country skiing 30 -k runs Triathlons Soccer Long-distance canoe racing Cycling events PBRC 2009 29

“Inappropriate” Activities for Carbohydrate Loading… Football games 10 -k runs Walking and hiking Most swimming events Basketball games Weight lifting Most track and field PBRC 2009 30

Fluids One nutrient that we don't often think about that is essential for a successful exercise program — fluids! It is important to monitor the hydration level of the physically active person. Many people are dehydrated subclinically, especially older individuals or people who are exercising in heat and, in these situations, hydration needs go up precipitously. PBRC 2009 31

Fluids Active people should be encouraged to drink more non-alcoholic, noncaffeinated fluids when they become physically active. At least eight (8 ounce) glasses of fluids per day. PBRC 2009 32

Dehydration Athletes that depend on weight class to enter an event run a risk of dehydration. As little as 3% loss of body weight as water impairs performance, particularly endurance events. PBRC 2009 33

0 2 Thirst Stronger thirst, vague discomfort Pe rc en tw ei gh tl os s Normal weight 4 6 8 Economy of movement, impatience, sleepiness, apathy Tingling in arms, feet, headache, increase in body temperature Dizziness, cyanosis, indistinct speech, mental confusion PBRC 2009 34

Normal weight Spastic muscles, general incapacity, delirium, failing renal function Pe rc en t we ig ht lo ss 10 15 Shriveled skin, inability to swallow, sunken eyes, painful urination Cessation of urine formation, cracked skin, bare survival limit 20 Death PBRC 2009 35

Exercising in Hot Climates Heat related illnesses include – heat cramps, heat exhaustion, and heat stroke. Heat cramps are deemed the most benign. They are characterized by painful spasms of the skeletal musculature, particularly the legs. The body temperature is usually normal. PBRC 2009 36

Exercising in Hot Climates Heat exhaustion is characterized by fluid depletion. Patients tend to present sweating profusely. Symptoms include headaches, nausea, vomiting, dizziness, and syncope. Treatment includes rest, rehydration (which often needs to be given intravenously), and cooling. PBRC 2009 37

Exercising in Hot Climates Heat stroke is a life threatening emergency defined as a high core temperature (>40 C°) accompanied by neurological symptoms. The presentation can range between a patient with minimal to no sweating, to a patient with profuse sweating. The patient should be moved to a cool environment, clothing removed and evaporative cooling of the skin encouraged by spraying tepid water over the body, while electric fans are directed at the patient. If available, bags of ice should be placed over the major vessels in the axillae, groin and neck or ice water baths. Heat stroke requires treatment in the ER. PBRC 2009 38

People who would not benefit from an exercise program Those with unstable medical conditions: • Unstable angina • Out-of-control diabetes • Uncontrolled blood pressure • Or patients who have experienced other serious medical events within the last six months – These listed individuals should not have a regular exercise program until their condition has better stabilized. Also not beneficial for those immediately after a major surgery, those with a progressive neurological disorder, or any type of progressive disease state that has not been stabilized. PBRC 2009 39

References Wardlaw G. , Kessel M. Perspectives in nutrition. 5 th ed. 2002. PBRC 2009 40

Pennington Biomedical Research Center Division of Education Phillip Brantley, Ph. D, Director Pennington Biomedical Research Center Claude Bouchard, Ph. D, Executive Director Heli J. Roy, Ph. D, RD Shanna Lundy, BS Beth Kalicki PBRC 2009 41

About Our Company The Pennington Biomedical Research Center is a world-renowned nutrition research center. Mission: To promote healthier lives through research and education in nutrition and preventive medicine. The Pennington Center has several research areas, including: Clinical Obesity Research Experimental Obesity Functional Foods Health and Performance Enhancement Nutrition and Chronic Diseases Nutrition and the Brain Dementia, Alzheimer’s and healthy aging Diet, exercise, weight loss and weight loss maintenance The research fostered in these areas can have a profound impact on healthy living and on the prevention of common chronic diseases, such as heart disease, cancer, diabetes, hypertension and osteoporosis. The Division of Education provides education and information to the scientific community and the public about research findings, training programs and research areas, and coordinates educational events for the public on various health issues. We invite people of all ages and backgrounds to participate in the exciting research studies being conducted at the Pennington Center in Baton Rouge, Louisiana. If you would like to take part, visit the clinical trials web page at www. pbrc. edu or call (225) 763 -3000. PBRC 2009 42