All of us, at some point or another, want to feel a little better about ourselves, get a bit stronger, increase stamina, and perform at the top of our game. But how can these desires be achieved? Check out the ways below that are supported by recent research.

Boost your self-image: You don't need to spend your money on pricey cosmetics and weight loss pills to feel better about yourself - a bout of good old exercise will do the trick. In a review of 57 studies that investigated the effects of physical activity on body image, researchers from the University of Florida found that exercise boosted self-image regardless of whether actual changes in body composition and fitness level occurred. Furthermore, the research results indicated that the effect on body image was greatest for those who exercised most often. The investigators conclude that the dose of exercise needed to improve self-image may be lower than that required to achieve physical benefits (e.g., improved exercise endurance).

Build stronger muscles: Performing one set of 8-12 repetitions per weight training exercise is sufficient to improve your strength. But, if you really want to see results you will need to add a few more sets to your routine. According to a review of the literature published in the September 2009 issue of the Journal of Strength Training and Conditioning Research, performing 2-3 sets per activity will increase your strength gains by 46% over what you can achieve by completing just one set.

Increase stamina: If you want to give your energy levels a boost midday, engage in a little low- to moderate-intensity exercise. Researchers from The University of Georgia found that the energy levels of previously inactive individuals who complained of chronic fatigue were increased by 20% when they engaged in either low- or moderate-intensity exercise for 20 minutes, 3 times per week for a period of 6 weeks compared to those subjects who did not exercise during that same time frame. Interestingly, low-intensity exercise was associated with a greater reduction in feelings of fatigue than was moderate-intensity exercise (65% versus 49%, respectively). The authors explained that for individuals who suffer from chronic fatigue, moderate-intensity exercise may be too difficult to perform.

Improve exercise performance: What does rest have to do with it? Plenty according to a Stanford University study that investigated the role of sleep patterns on athletic performance in members of Stanford's Women's tennis team. The athletes experienced improvements in hitting depth and accuracy of serves as well as better sprint drill times after a 5-6 week period during which they aimed to get 10 hours of sleep per night. Adequate sleep is essential because it is during sleep that the body restores and heals itself, especially after long bouts of intense exercise and training. Bottom line, the harder your workouts, the more hours of sleep you may need to get at night.

Note: Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources:

J Health Psychol 2009: 14: 780, "Effects of Exercise Interventions on Body Image: A Meta-analysis," Campbell, A. and Hausenblas, H.

Journal of Strength and Conditioning Research, September 2009, Volume 23, Issue 6 - pp. 1890-1901, "Single Versus Multiple Sets of Resistance Exercise: A Meta-Regression," Krieger, J.W.

University of Georgia Office of Public Affairs news release, February 28, 2008, "Low-intensity Exercise Reduces Fatigue Symptoms by 65 Percent, study finds," Puetz, T.

American Academy of Sleep Medicine news release, June 8, 2009, "Study Shows Sleep Extension Improves Athletic Performance and Mood," Mah, C.

Are you at risk for a magnesium deficiency? You could be if you are active, especially if you engage in intense exercise. Magnesium is lost through your sweat as you exercise. An increase in urinary output from vigorous physical activity also results in magnesium loss. According to the results of the 1999-2000 National Health and Nutrition Examination Survey, a large number of the general population fail to meet the Dietary Reference Intake (310-420 mg/day based on age and gender). This insufficient intake, in combination with intense exercise, increases your risk for developing a deficiency.

Magnesium has many roles in your body. It is involved in more than 300 biochemical reactions according to The National Institutes of Health, Office of Dietary Supplements. Some of these include:

• Nerve conduction
• Muscle function
• Regulation of heart rhythm and blood pressure
• Energy metabolism
• Protein synthesis
• Regulation of insulin and blood sugar levels
• Maintenance of a healthy immune system

Data from several studies have shown that athletes, particularly those involved in weight-class and body-conscious sports such as skating, gymnastics, ballet, wrestling, and tennis, have suboptimal levels of magnesium. Although more research needs to be conducted, there is some evidence to indicate that exercise endurance is affected by low levels of magnesium, with a deficiency increasing the body's need for oxygen at submaximal workloads.

Insufficient intake of magnesium is associated with an increased risk for chronic health conditions such as metabolic syndrome and type 2 diabetes. Researchers are investigating the role of magnesium in the prevention and management of high blood pressure and cardiovascular disease.

Factors that can lead to magnesium deficiency:

• Insufficient intake
• Older age - older adults tend to have a lower intake of magnesium compared to younger individuals, regardless of race and gender
• Intense exercise
• Exercising in hot and humid environments which promote greater sweating rates
• Poor health of the digestive and kidney systems (magnesium is absorbed via the small intestines and excreted by the kidneys)
• Certain medications can increase urinary excretion of magnesium, such as diuretics
• Poorly-managed diabetes
• Alcoholism
• Stress

Signs and symptoms of magnesium deficiency:

• Loss of appetite
• Nausea/vomiting
• Feelings of stress are worsened
• Sleep disturbance
• Muscle spasms/cramps
• High blood pressure
• Irregular heart rhythm
• Depression/change in personality

The signs and symptoms associated with magnesium deficiency are general and can be the result of other medical conditions. Contact your physician if you are experiencing any of the above conditions. He or she will give you a thorough examination and may perform blood tests. You may also receive a referral to a nutritionist or registered dietitian who may give suggestions on how you can increase your intake of magnesium.

Some of the literature suggests that active individuals, especially those involved in intense exercise regimens, may benefit from an increase in magnesium intake by 10-20% above values recommended for the general population. Good food sources of magnesium include dark-green, leafy vegetables (spinach), legumes, nuts (almonds and cashews), and whole grains (oatmeal and wheat bran/germ).

Resources:

The Coaches' Guide to Sports Nutrition, 2007, Benardot, D. and Thompson, W.R.

ACSM's Health & Fitness Journal, January/February 2008, Volume 12, Number 1, pp. 33-35, "Magnesium and Athletic Performance," Volpe, S.L.

National Institutes of Health, Office of Dietary Supplements: "Magnesium"

ACSM, ADA, DC Joint Position Stand "Nutrition and Athletic Performance," 2009 Medicine & Science in Sports & Exercise

Fat - is it friend or foe to the active individual? In the past, fat has been demonized by nutritionists and health care professionals alike because of its link to an increased risk for chronic disease. A high-fat diet (more than 70% of total caloric intake) does not bode well for the competitive athlete and the American College of Sports Medicine (ACSM), along with the American Dietetic Association (ADA) and Dietitians of Canada (DC), in their Joint Position Stand on Nutrition and Athletic Performance, recommend against it. But, a certain amount of fat, and from the right source, is necessary for proper functioning of your body, whether you are physically active or not. The ACSM, ADA, and DC state in their joint position stand that consuming less than 20% of your total caloric intake from fat does not enhance athletic performance. Fat should be a part of a healthy, well-balanced diet.

Why do you need fat in your diet?

• Fat is a constituent of cell membranes.
• Fat is needed in the production of hormones, such as testosterone and estrogen.
• Fat is needed for the storage of the fat-soluble vitamins, A, D, E, and K.
• It is a source of essential fatty-acids.
• It is a source of energy/fuel for your body.

What are the different types of fat?

• Saturated fats are fatty acids whose carbon atoms are saturated with hydrogen atoms. Saturated fats are typically solid at room temperature (lard, butter, etc.,). They can be categorized as long- or medium-chain saturated fats and are metabolized differently by your body. Long-chain saturated fats, found in foods such as bacon, are linked with higher LDL ("bad" cholesterol) levels. Medium-chain saturated fats, such as found in coconut oil, are metabolized by the liver to provide energy for the body and are not linked with increased LDL values. They are associated with health-promoting characteristics, such as protection against heart disease and aiding in weight loss. Some even purport that medium-chain saturated fatty acids may improve athletic performance because of the means by which they are metabolized by your body. Food sources of medium-chain saturated fats should be chosen over those with long-chain saturated fatty acids.
• Monounsaturated fats are fatty acids that have one carbon molecule that isn't bound to hydrogen. They are typically liquid at room temperature and when refrigerated, start to solidify. Olive and canola oils are examples of monounsaturated fats. When the diet is low in saturated fat, monounsaturated fats can decrease your risk for cardiovascular disease and lower your LDL levels.
• Polyunsaturated fats are fatty acids that have more than one carbon molecule that are not bound to hydrogen. These fatty acids are liquid at room temperature and when refrigerated. They include such oils as sesame and sunflower. Polyunsaturated fats have been linked with improved cholesterol levels.
• Trans fats are unsaturated fats that have been altered by adding hydrogen atoms so that they remain solid at room temperature. These include your hydrogenated vegetable oils that are found in margarine. Trans fats raise both total and LDL cholesterol levels while lowering your HDL ("good" cholesterol) values.

How much fat should you consume per day?

• Total fat consumption should not exceed 20-35% of your total energy intake, which is dependent upon your age, activity level, and body weight goals. The American Heart Association (AHA) states that if you are overweight, you should not consume more than 30% of your total daily caloric intake from fat.
• The AHA recommends that your intake of saturated fats should not exceed 7 percent of your total daily caloric intake.
• The Dietary Guidelines for Americans recommends that intake of unsaturated fatty acids should comprise approximately 10% each from monounsaturated and polyunsaturated sources of your total daily energy intake.
• Consumption of trans fats is strongly discouraged and should not exceed more than 1% of your total daily calories.

Healthy sources of fat:

• Olive, soybean, canola, sunflower, and coconut oils
• Lean cuts of meat
• Fish, such as salmon and tuna
• Seeds, such as sunflower and flaxseed
• Nuts, such as almonds

Sensibly including fat in your diet can help you to achieve optimal health. Diets extremely low in fat have been linked to depression, nutrient deficiencies, low energy levels, poor concentration, and even weight gain. Fat can be the active individual's friend when consumed from healthy sources and in the right proportions.

Resources:

American Heart Association

Food for Fitness, Eat Right to Train Right, 2004, Carmichael, C.

The Encyclopedia of Healing Foods, 2005, Murray, M.

OnFitness, November/December 2009, pp.68-69, "Fat Science."

Joint Position Statement Nutrition and Athletic Performance, The American College of Sports Medicine, The American Dietetic Association, and Dietitians of Canada

Chicken noodle soup has been purported to alleviate symptoms of the common cold and to improve digestion. Deemed as a comfort food by many, it is even said to "warm the soul." But did you know that it may help you stay hydrated during exercise? The results of a study published in the November 2009 issue of Medicine & Science in Sports & Exercise indicate that it might.

Nineteen college-age subjects underwent three testing sessions, each separated by at least one week, during which a different liquid, (chicken noodle soup, water, and a commercially-prepared carbohydrate-electrolyte drink) was consumed 45 minutes prior to exercise (90 minutes of steady-state exercise followed by a 5 minute rest and then participation in a physical performance task). Fluid balance during the exercise was improved after 355 ml (1 1/2 cups) of chicken noodle soup was consumed in comparison to the trials during which either water or the carbohydrate-electrolyte drink was consumed. The enhanced fluid balance associated with the soup consumption was achieved through an increased rate of water intake ad libitum (i.e., as one so wishes) during exercise and a decreased amount of water lost in urine.

The investigators noted that a higher plasma osmolality occurred with the consumption of the chicken noodle soup, which has a greater electrolyte concentration (sodium content) compared to water. They state that the higher plasma osmolality was the driving force behind the greater water intake ad libitum, which in turn, led to the improved fluid balance. In addition, the researchers sited findings of previous research that indicate when fluids with high electrolyte concentrations (such as chicken noodle soup) are consumed before exercise, the body conserves the ingested water during the physical activity. This fluid retention contributes to improved fluid balance.

The investigators of the current study did not note an effect on physical performance when chicken noodle soup was consumed compared to the water and carbohydrate-electrolyte drink trials. However, they suggest that the greater water intake and subsequent improved fluid balance may postpone the onset of exercise-induced dehydration during an extended exercise session and/or physical activity in a hot and humid environment. The researchers conclude that chicken noodle soup is an acceptable alternative for improving hydration status during aerobic exercise.

Note: Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources

Medicine & Science in Sports & Exercise, Volume 41, Number 11, November 2009, pp .2017-2025, "Effect of Preexercise Electrolyte Ingestion on Fluid Balance in Men and Women," Johannsen, N.M. et al,.

Nourishing Traditions, 2001, Fallon, S.

The Encyclopedia of Healing Foods, 2005, Murray, M.

     With the onset of warm weather comes the increased risk of exercise-related dehydration.  Sweating, a protective mechanism of your body, regulates your body temperature.  As your sweat evaporates, heat is dissipated.  This prevents your core body temperature from rising to dangerously high levels.  The rate at which your body sweats is dependent upon the intensity and duration of the exercise, environmental conditions, acclimatization, type and amount of clothing worn, individual biological differences, and your hydration status before exercise.

     Dehydration can result if fluid consumed does not match fluid lost from exercise.  When you are dehydrated your risk for heat-related illnesses increases and your exercise performance becomes impaired.  Physiologic function of the body starts to be compromised when 1%-2% of body weight is lost as a result of fluid loss.  Your risk for heat-related illnesses increases when 3% or more of your body weight is lost as a result of fluid loss.  If you are well-hydrated before exercise, it could take only one hour of exercise for this to occur, sooner if you are dehydrated from the start.

     An understanding of the signs and symptoms of dehydration is important in order for you to take appropriate action when they occur.

Signs and Symptoms of Dehydration

• Thirst
• Headache
• Nausea
• Vomiting
• Dizziness
• Cramps
• Weakness
• Chills

     You can reduce or prevent the likelihood of becoming dehydrated by following certain guidelines.  These include adhering to a fluid replacement schedule and incorporating steps to optimize your fluid replacement.

Fluid Replacement Schedule

Pre-Exercise

• Drink 17-20 fluid ounces of water or sports drink 2-3 hours before beginning exercise
• Ingest 7-10 fluid ounces of water or sports drink 10-20 minutes before exercise

During Exercise

• Ingest 7-10 fluid ounces every 10-20 minutes

Post-Exercise

• Drink approximately 16-20 fluid ounces of water or sports drink for every pound of weight lost from the activity within 2 hours after completing your exercise session

     If you find it difficult to adequately rehydrate, there are some tactics you can follow to optimize fluid replacement.

Steps to Optimize Fluid Replacement

• Carry water bottle with you while you exercise
• Choose a water bottle with measurement markings to keep track of the amount of liquid consumed
• Choose drinks that are palatable, such as flavored water or sports drink

Characteristics of Fluid to be Consumed

• Palatable
• Cool.  The ideal temperature range of the drink is 50-59 degrees Fahrenheit (10-15 degrees Celsius)
• Post-exercise drink should include a carbohydrate source, especially if your session lasts more that 45 minutes, to replenish glycogen (energy) stores 
  
• Contains electrolytes, such as sodium chloride (0.3 - 0.7 g/L), to offset loss from sweat and to reduce your risk for conditions associated with electrolyte imbalance (muscle cramps) - this is particularly important if exercise lasts longer than 4 hours and during the initial days of warm weather when your body hasn't yet been acclimated.

Drinks to Avoid

• Caffeinated and alcoholic beverages which can increase fluid loss through increased urine output
• Carbonated beverages which may lead to a "full" sensation causing you to decrease your fluid intake
• Drinks with carbohydrate concentrations that are greater than 8% are not recommended to drink during exercise because they interfere with stomach emptying and intestinal absorption
  

Resources

Journal of Athletic Training, 2000:35(2):212-224; "National Athletic Trainers' Association Position Statement: Fluid Replacement for Athletes," Casa D.J. et al.

Track Shack - Sports Nutrition Developed by the Gatorade Sports Science Institute www.trackshack.com

     Can Vitamin D enhance exercise performance?  Vitamin D has been a topic of discussion lately as experts debate whether or not the current recommended daily intake is sufficient to meet the needs of the body.  Vitamin D is a fat-soluble vitamin (can be stored in body fat) and a hormone (conversion occurs in the skin to be sent to the liver and kidneys for further conversion to a useable form in other areas of the body).  Our primary source of Vitamin D comes from the sun.  Fortified foods, such as milk, are the next prominent source.

     Vitamin D is "inactive" and in order for it to become "active", and useable by the body, it has to go through hydroxylation.  This process starts in the liver where Vitamin D becomes 25-hydroxyvitamin D (25(OH)D).  Further conversion occurs in the kidneys where it becomes 1,25-dihydroxyvitamin D (1,25(OH)2D).  Adequate blood levels of Vitamin D, 40-100 nmol/L, are determined by measuring blood levels of 25(OH)D.  Modern day man's habits, such as sunscreen use and increased participation in indoor activities, have reduced our exposure to the sun's Vitamin D producing rays.  This, in turn, increases the risk for becoming deficient.  In order to achieve sufficient levels for body systems to function, dietary intake of Vitamin D needs to be increased to compensate for the decreased sun exposure.

     Adequate levels of Vitamin D are needed by the body to promote calcium absorption, bone health and muscle function, to maintain normal blood levels of calcium and phosphorus, for homeostasis of the nervous system, to regulate cell production, and for protein synthesis.  Vitamin D's role in enhancing exercise performance has been recently speculated.  An extensive review of the literature by Cannell et al., published in the May 2009 issue of Medicine & Science in Sports & Exercise, suggests that it can for individuals who are Vitamin D-deficient, especially for those who participate in indoor athletics (gymnastics) or who live at the northern latitudes.  The extra stress that exercise places on the metabolic pathways in which micronutrients, such as Vitamin D, play a role may indicate that there is a greater need for, and hence a greater intake required, of Vitamin D.  In addition, athletes are more likely to engage in dietary practices that limit Vitamin D intake, such as restricting total energy consumption and eliminating one or more of the food groups.

     Cannell et al.'s review of the literataure discovered that many studies have shown exercise performance to be seasonal.  That is, individuals perform at their best when 25(OH)D is at its peak in the late summer (when sun exposure has been greatest).  Exercise performance then starts to decline in early autumn as sun exposure decreases, and subsequently 25(OH)D levels decline.  In late winter, when sun exposure is very limited, and 25(OH)D levels are at their lowest, so is athletic performance.  This phenomenon suggests adequate levels of vitamin D are needed for optimum performance.  Cannell et al. also cited literature that indicated Vitamin D has been shown to increase the size and number of Type II (fast twitch) muscle fibers.

     Do these findings mean that everyone who wants to enhance their physical performance should start supplementing with Vitamin D?  No.  If you consume a nutritionally adequate, well-balanced diet, your Vitamin D levels should be sufficient to meet the demands of exercise.  There is no evidence that Vitamin D levels above normal will increase exercise performance.  In fact, taking mega-doses of Vitamin D can lead to toxicity.  Scientific findings only indicate that individuals who are Vitamin D-deficient can benefit from increased sun exposure and dietary intake or through Vitamin D supplements.

     If you think you may be Vitamin D deficient you should consult your physician to have your blood levels tested.  You may also want to consider having your diet reviewed by a registered dietician who has experience counseling active and athletic individuals.

Note:  Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources:

Medicine & Science in Sports & Exercise, Vol. 41 No.5 May 2009, "Athletic Performance and Vitamin D,"pp. 1102-1109.  Cannell, JJ et al.

ACSM's Health & Fitness Journal Vol. 12, No. 5 September/October 2008, "Vitamin D and Health: Do We Need More Than the Current 

DRI?," pp. 34-36. Volpe, S.L.

The Encyclopedia of Healing Foods, Murray M., Pizzorno, J., and Pizzorno L.

American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada Joint Position Statement "Nutrition and Athletic Performance," Medicine & Science in Sports & Exercise, pp. 709-731.