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How to adjust carbohydrate intake
How to adjust carbohydrate intake is the third article in this short series dedicated to this important source of fuel for physical activity. We have described what are carbohydrates and the use of carbohydrate for sports. In theory, carbohydrate requirements can be calculated knowing a few variables, however in practice there is often a mismatch between estimated and actual requirements. Sources of mismatch Wrong calculations Biological factors These include insulin sensitivity and glucose oxidation rates, which will determine how much carbohydrate the athlete can actually use for fuel. Health conditions Actual vs predicted output In many cases, this is the biggest source of mismatch. Some athletes can predict with a…
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Carbohydrate for sports
The use of carbohydrate for sports has been well-known for several decades. The amount and timing of carbohydrate intake depends on many factors, including the duration, intensity and type of exercise. Roles of carbohydrate in sport As seen in the previous article, the main role of carbohydrate in the body is the production of energy. During exercise, this can translate to: In the time between training or competition bouts, carbohydrate intake is important to: The amount of carbohydrate an athlete requires during and around exercise depends on several factors: It is important to mention the fact that the individual factors listed above can change with habits. When it comes to…
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Sodium in sports
At the population level, health authorities recommend limiting sodium intake to prevent chronic conditions. However, the role of sodium in sports is more complicated, as this electrolyte plays important roles related to performance and recovery. Roles of sodium As seen in the article How much salt is too much?, sodium has roles in the maintenance of plasma volume and transmission of nerve impulses. In addition, it is needed for muscle contraction and glucose transport into cells. As a reminder, glucose is essential for energy production during most types of exercise, as well as recovery post-exercise. Sodium in sports How do we lose sodium The main ways we lose sodium is…
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Training the gut
Training the gut is a sports nutrition strategy designed to allow athletes to handle increased amounts of food and fluid to meet their training and competition requirements. Gastrointestinal symptoms Many athletes, particularly those participating in intense and/or prolonged exercise, suffer from gastrointestinal (GI) discomfort. The symptoms are highly individual and can include bloating, abdominal cramping, diarrhea and vomiting (1, 2). On the most severe end of the spectrum, athletes may experience ischemic colitis and small bowel infarctions, which may require surgical resection (2). Regardless of severity, GI symptoms can certainly affect both performance and recovery (2). Factors The following factors play a role in the development of gastrointestinal symptoms in…
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Exercise and bone health
It makes intuitive sense that exercise and bone health are tightly related. Regular exercise can help prevent bone loss and decrease the risk of falls and fractures later in life. Exercise can help with muscle strength and bone strength, improving balance (1). At the same time that the muscle contraction during exercise leads to muscle grow, it also causes mechanical strain on the bones, leading to bone adaptation (1). As seen in the article Nutrients for bone health, bone tissue undergoes opposing processes of resorption and formation. Therefore, bone loss occurs when resorption is greater than formation. Most (about 90%) of our peak bone mass is gained from infancy until…
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Sleep and nutrition in athletes
Sleep and nutrition in athletes is an often overlooked aspect of recovery and performance. In this article, we explore the multiple factors that can affect an athlete’s sleep quality and quantity. Sleep in athletes Many athletes suffer from sleep issues, including short duration of sleep (a.k.a. sleep deprivation) and sleep disturbances (e.g. insomnia, waking up at night) (1, 2). The factors that may contribute to sleep issues in athletes include: Muscle soreness (1) and pain Intense training (1) Early or late training sessions or competition (2, 3, 4) Poor sleep hygiene, including screen use close to bedtime (2, 3) Stress, nerves and/or anxiety due to competition or other reasons (2,…
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How to prevent and reduce DOMs
If you have ever engaged in exercise, chances are you have experienced delayed-onset muscle soreness, a.k.a. DOMs. In this article we explore how to prevent and reduce DOMs. What is DOMs Delayed-onset muscle soreness (DOMs) describes the tenderness and soreness that may be experienced after exercise. It normally peaks 24-72 hours after exercise and goes away after 5-7 days (1). DOMs typically occurs after performing exercises one is not used to (i.e. unaccustomed exercise) and/or eccentric exercise (i.e. controlled lengthening of muscles) (1, 2, 3). The most commonly cited potential causes for DOMs include lactate build-up in muscles, inflammation, muscle spasm, muscle/connective tissue damage, increased muscle temperature (1, 3). There…
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Why do we keep breaking World and Olympic records?
If you watched the Tokyo 2020 Olympic games you would have noticed there were many records broken, often by the same athlete. Why do we keep breaking World and Olympic records? Of course there is no one answer to this question and this is not meant to be a prescriptive article, but more of a thought process around the fact that records are broken all the time. The great and humble Georges St Pierre said that MMA fighters of today are better than fighters of his generation and future fighters will be better than current ones. It is a fact of sports because all the disciplines that support athletic performance…
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Exercise, gut health and gastrointestinal issues
Exercise is generally regarded as beneficial for health. Gut health is not an exception, athletes tend to have microbiomes with increased composition and/or function. However, too much exercise can be detrimental. This is an overview on exercise, gut health and gastrointestinal issues. Exercise and gut health Most people will agree that exercising is beneficial for health. When comparing the microbiomes of exercising individuals (including athletes) with those of sedentary individuals, scientists have found: More bacterial diversity and/or richness, generally regarded as beneficial to health More short-chain fatty acid (SCFA) metabolic pathways, important for intestinal integrity and other aspects of health Increased metabolic pathways of amino acids (including branched-chain amino acid,…
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Protein requirements for female athletes
Are protein requirements for female athletes the same than those of male athletes? Although it makes sense to think that body composition, energy metabolism and sex hormones may play a role in nutrient requirements, there are no fast and hard rules, but sensible guidelines as detailed below. Protein requirements for female athletes In theory, female athletes should have slightly lower protein requirements than their male counterparts because oestrogen causes exercising female bodies to increase fatty acid oxidation and decrease amino acid (and carbohydrate) oxidation (1, 2). Moreover, protein catabolism is higher in the luteal phase when oestrogen and progesterone are high (1). On the other hand, some studies seem to…
