When we recommend carbohydrate intake for the day, it is often expressed as grams per kg bodyweight. For example, for most sports this will be between 5 and 8 g/kg with values up to 12 g/kg on some days, in some sports. Protein intake is also expressed per kg body weight or per kg fat-free mass and this makes sense. However, when it comes to carbohydrate intake during exercise, recommendations are provided in grams per hour. A recent study challenged this view. Should we real

The definition of relative energy deficiency in sport (REDs) is that low energy availability (LEA) is the cause of a wide range of symptoms that are common amongst athletes. In the current REDs model, low energy availability is depicted at the centre of a wheel with numerous spokes. Each spoke represents a grouping of symptoms or suggested consequences of LEA. Considering LEA is central to the REDs model, this blog asks the question: can we measure LEA? Challenges defining lo

Below are the 5 most popular blogs on mysportscience in 2024! Click the title to read... 1. HMB: a magic supplement? In top spot this year is an older, but always popular blog on HMB. In this blog, Asker discusses the potential ergogenic effect of the supplement β-hydroxy-β-methylbutyrate (HMB); a supplement carrying very little evidence to support its popularity. The blog synthesises evidence from a review by Jakubowski et al. (2020) to highlight the effect of HMB (or lack

In our recent paper, “ Does REDs exist? ”, we raise some important questions about the REDs concept and supporting evidence (1). This blog covers whether low energy availability (LEA), considered the cause of REDs, leads to ‘immunosuppression’ or ‘immunological dysfunction’ in athletes, as has been suggested. Interest in this topic has been stoked by observations that leanness and LEA are associated with the recall of illness symptoms in athletes. Are infections a serious pro

With increasing age muscle strength, lean/muscle mass and functional ability decline. This is commonly referred to as sarcopenia. Sarcopenia decreases the ability to perform activities of daily living (1). It is also associated with reductions in bone mass/strength and cognitive function (2). Creatine has been proposed as a possible countermeasure of sarcopenia. Accumulating research over the past few decades shows that creatine supplementation, primarily when combined with r

“Does REDs exist?” is the title of a paper we recently published (1). After many years assuming REDs was based on a solid evidence base,...

One of the most researched supplements on the market is creatine. Creatine combined with strength training has been shown to consistently help individuals gain more muscle mass, strength, power, and muscle function across the lifespan (from adolescents to older adults). The effects on endurance performance are much less studied, but there is a growing body of evidence that creatine can benefit endurance athletes in critical race situations such as finishing kicks or breakaway

Ketone ester supplements continue to receive attention from athletes for their claimed potential to enhance endurance exercise performance. The basis of this interest stems from being able to drink this supplement and quickly induce ketosis (high blood levels of ketone bodies) without the need to restrict dietary carbohydrate (for example, adhering to a ketogenic diet). It is becoming increasingly clear that ketone supplements influence exercise responses, however scientists

There are countless times I have watched sports on TV and commentators provide their insights on the regulation of fuel use. “And then you switch to fat metabolism” is one of the commonly heard catch phrases. Last weekend this happened again when I was watching cycling. But it is a myth that we have a switch that allows us to select different fuels. How does it work? Please pass this one on to TV commentators. Energy for muscle contraction When we exercise the muscle contract

More protein is often considered better. Here we discuss findings from a study linking a high protein intake to CVD risk?

In a series of previous blogs on mysportscience, the role of blood glucose was discussed and we highlighted what insights Continuous Glucose Monitoring (CGM) can provide athletes now and possibly in the future. In this blog, Dr Nicola Guess highlights the multifactorial nature of glucose metabolism, challenging the notion of straightforward causal links between food intake and glycemic responses. In previous blogs Dr Mike Riddell and I discussed opportunities and also some li

Current sports nutrition guidelines recommend distributing protein intake in multiple equal meals throughout the day (1). This concept of protein distribution is primarily based on studies suggesting that only a limited amount of protein ingested in a single meal can effectively be used for muscle protein synthesis (the process that allows muscle to recover and adapt to training). It was believed that there is a linear increase in muscle protein synthesis up to doses of appro

Glycogen is essential for high intensity exercise performance. A review concluded that elevated glycogen concentration can improve performance by 2-3% and endurance capacity by 15-25%. Muscle glycogen concentrations can be increased by eating a diet that is rich in carbohydrate. However, studies in the 70s suggested that extreme glycogen loading protocols resulted in very high muscle glycogen concentrations. These protocols employed combinations of high carbohydrate days, low

In previous blogs we have discussed the role of protein intake for muscle protein synthesis. However, muscle contains many different...

Fructose can constitute a substantial energy source in the human diet. It is a dispensable (non-essential) nutrient, and no adverse...

In 2003, we discovered that certain combinations of carbohydrate could be absorbed faster in a sports setting. Before this discovery it was believed that the maximal amount of carbohydrate that could be delivered to the muscle was around 60 grams per hour (or 240kcal per hour). With energy expenditures over 1000 kcal/h in some endurance sports it was speculated that delivering more carbohydrate would help performance. This blog outlines the science behind carbohydrate ratios

The question of whether mild dehydration (~2-3% body mass loss) really affects athletic performance is crucial. While several studies...

Iron deficiency is a prevalent issue among athletes, which can significantly affect training consistency and performance if left...

It's 4:30 AM as the laces of the thick soled fire boots are tightened. The only light comes from a headlamp and the inside of the tent is...

CGM is a tool that can give us insights into “blood glucose” in real time! Although we must understand the limitations and be wary of not over interpreting or wrongly interpreting any data that is obtained, the technology can also be really useful for athletes. In this blog we discuss how CGM can best be used! There are a number of very clear and straightforward applications for your CGM. Most of these are related to individual glucose responses to things like foods, meals an