It’s heatwave season and soaring temperatures are adding an extra challenge to our workouts. How can you mitigate the effects, stay cool and keep exercising?
To be able to perform well in the heat, you need to be efficient at shedding heat and replacing lost water – but how exactly?
What happens in the body when you exercise in the heat?
The fatigue and loss of power you experience during very warm weather workouts is caused by two main factors: a rise in core body temperature and changes in your metabolism. Both the exercise itself and the air temperature and humidity can increase your core body temperature, putting stress on your cardiovascular system.
To help cool itself, your body sends more blood to the skin. This leaves less blood available for your muscles, and your heart has to work harder. Losing fluid in the form of sweat through the skin means blood volume decreases and your heart’s stroke volume decreases.
The most effective method of getting rid of excess heat during exercise is sweating, whereby the moisture on the surface of your skin cools you down as it evaporates. Staying on top of your hydration is crucial when exercising in the heat.
Dehydration difficulties
Hot conditions plus dehydration can lead to a drop in performance and, at worst, a dangerous rise in your core body temperature. If your body’s temperature exceeds 39ºC, you’ re at risk of developing heat-related illness – heat stress, heat exhaustion and heatstroke – stated in ascending order of severity.
Generally, performance starts to decrease when you lose 2% of your body weight as fluid through sweating. You may see anywhere between zero and 20% drop in performance.
Cooling strategies
Reduce the duration and intensity of your workout.
Exercise early in the day or later in the evening to avoid the worst of the heat – avoid exercising in the hottest part of the day
If you’re exercising outdoors, seek the shade as much as possible.
Sip an ice-cold drink or ice slushy (crushed ice + water) just before you exercise – this will pre-cool your body
Pour or spray water over your skin to aid heat evaporation
Put ice cubes inside your helmet, socks or jersey.
Make sure you’re hydrated
Dehydration is a key factor in heat-related illness. Staying hydrated helps your body sweat so will help lower your core temperature. Ideally, you should drink enough so that you keep your fluid loss below 2% body weight. That’s equivalent to a weight loss of 1.4kg for a 70kg person.
If you’re doing exercise that lasts less than two hours, where sweat losses are relatively small, you should only drink when thirsty. Over-hydrating can be as problematic as dehydration, causing a potentially dangerous imbalance in the body’s salt levels.
But if you’re sweating heavily or exercising longer than 2 hours you may need to be more proactive in your drinking strategy to avoid becoming dehydrated.
Can electrolytes help performance?
Although you lose electrolytes in sweat, you don’t need to replace them during workouts of less than two hours. You have enough sodium in your body to replenish sweat losses. By taking extra sodium in tablets, you could be pushing your overall salt intake too high. Only athletes sustaining heavy sweat losses, for example during workouts or races of longer than two hours are likely to see any benefit. But even then, the benefit is on longer-term sodium balance, not performance in any single event. It is a good idea to replace sodium after exercise, though most of us have plentiful salt in our regular daily diet to cover these needs.
Riders who suffer from cramps during long, hot rides, sportives or races often blame poor hydration or lack of electrolytes. However, recent studies have indicated that this isn’t always the case, and the exact reason for cramping is still unknown.
Heat adaptation training
If you know you’ll be racing in hot, humid conditions, doing heat adaptation training a few weeks beforehand will help you perform better.
If you can’t travel to a hot country before your race, the alternative is to simulate the conditions by wearing extra clothing while training or immersing yourself in a hot bath (40ºC) for 45 minutes.
You’ll need to raise your core temperature by 1.5ºC for at least 60 minutes daily for 10 – 15 days until a few days before your target race.
How do you know whether you know whether you are heat adapted? Your resting and exercise heart rate will be lower for the same power output, and you’ll start sweating earlier in your session or at a lower ambient temperature.
The Complete Guide to Sports Nutrition, ninth edition is the definitive practical handbook for anyone wanting a performance advantage. This fully updated and revised edition includes guidance on:
maximising endurance, strength, performance and recovery
the most popular sports supplements
relative energy deficiency in sport (RED-S)
hydration strategies
nutrition for masters athletes, young athletes and plant-based athletes
nutrition preparation for competition
gut health and how to avoid gut problems during exercise
Not sure how much carbs to consume before, during and after exercise? With so much noise around low-carbohydrate and ketogenic diets, its easy to get confused as to how much carbohydrate you really need. Here’s a summary of the current carbohydrate recommendations for fuelling your body.
This is an abridged extract from The Complete Guide to Sports Nutrition (9th edition)
Why is carbohydrate important for performance?
Carbohydrate is the preferred fuel source for the brain, nervous system and heart and is used by the muscles to fuel both aerobic and anaerobic activities. Carbohydrate offers advantages over fat as a fuel since it provides more energy per volume of oxygen. It is, therefore, considered a more efficient fuel and is the fastest way for your body to produce energy.
Any glucose that’s not needed immediately for energy is converted to glycogen, which is stored in the cells of the liver and muscles. The liver can store a maximum of 100g of glycogen and the muscles a maximum of 400g, equivalent to a total of 500g or 2000 kcal worth of energy in an average person. This is relatively small compared to your fat stores. Most people have 90 – 120 minutes’ worth of glycogen they can use when doing high-intensity aerobic exercise. When glycogen stores are depleted fatigue sets in and you will need to reduce your intensity.
During exercise, glycogen is broken down into glucose and delivered to the muscle for energy. You’ll burn a mixture of fat and carbohydrate, but the more intense your workout, the more your body relies on carbohydrate for fuel.
Carbohydrate recommendations
The exact amount of carbohydrate you need to consume depends on the goals of your workout. When you want to maximise your performance, i.e. do high intensity training, daily carbohydrate intakes should match the fuel needs of training and glycogen replenishment. In this scenario, the following recommendations are appropriate:
Activity level
Recommended daily carbohydrate intake (g/ kg body weight)
Very light training (low-intensity or skill-based exercise)
Your pre-exercise meal should provide 1–4 g carbohydrate per kg body weight, depending on exercise intensity and duration, and should be consumed between 1 and 4 hours before exercise.
Exercise < 45 minutes
If you’re exercising for less than 45 minutes, there is no performance advantage to be gained by consuming additional carbohydrates.
Exercise 45 – 75 minutes
When you’re doing high-intensity exercise lasting between 45 and 75 minutes, simply swilling (not swallowing) a carbohydrate drink in your mouth (‘mouth rinsing’) may improve performance. The carbohydrates stimulate oral sensors that act on the central nervous system (brain) to mask fatigue and reduce perceived exertion, thus allowing you to maintain exercise intensity for longer.
Exercise > 60 minutes
But for exercise lasting longer than about 60 minutes, consuming carbohydrate will help maintain your blood glucose level, delay fatigue and enhance your performance. The consensus recommendation is an intake of 30–60 g carbohydrate/hour, depending on the exercise intensity and duration. For low-moderate intensities, 30g/ hour is probably enough.
Exercise > 2 ½ hours
Previously, it was thought that the body could absorb no more than 60 g carbohydrate per hour. However, this relates to single source carbohydrates, such as glucose. Newer research suggests that it is possible to absorb more than this amount, as much as 90 g, if this comes from multiple transportable carbohydrate sources(e.g. glucose and fructose). A 2:1 mixture of glucose + fructose is less likely to cause gut problems than single carb sources.
Exercise duration
Recommended amount of carbohydrate
Type of carbohydrate
< 45 minutes
None
None
45–75 minutes
Very small amounts (mouth rinse)
Any
1–2.5 hours
30 – 60 g/h
Any
> 2.5 hours
Up to 90 g/h
Multiple transportable carbohydrates (glucose or maltodextrin + fructose)
500 ml isotonic sports drink (6 g carbohydrate/100 ml)
Two (40 g) Medjool dates
2 x 35g fruit and nut bars
One (45g) energy bar
One (50 g) energy gel
After exercise
If you plan to train again within 8 hours, it is important to begin refuelling as soon as possible after exercise. To promote rapid post-exercise recovery, aim to consume 1.0–1.2 g carbohydrate/ kg BW/ hour for the first 4 hours after exercise. Moderate and high glycaemic index (GI) carbohydrates will promote faster recovery during this period. When carbohydrate intake is suboptimal for refuelling, adding protein to a meal/snack will enhance glycogen storage. However, for recovery periods of 24 hours or longer, the type and timing of carbohydrate intake is less critical, although you should choose nutrient-dense sources wherever possible.
Should you go low carb?
The concept of ‘training low but competing high’ as well as ‘carbohydrate periodisation’ (integrating short periods of ‘training low’ into the training programme) has become very popular among elite endurance athletes. Strategies include occasional fasted training, training following an overnight fast, and not replenishing carbohydrate stores after the first of two training sessions of the day.
Training in a glycogen-depleted state may amplify the adaptive responses to endurance exercise, such as mitochondrial biogenesis, and increase the muscles’ ability to use fat for fuel. However, there are drawbacks: exercise feels harder and results inevitably in a reduction in training intensity. For this reason, it is important to undertake high-intensity training sessions with high carbohydrate stores.
Chronically training with low glycogen stores can impair the muscles’ ability to store and use carbohydrate during high-intensity exercise. Another disadvantage of repeatedly ‘training low’ is the risk of illness, injury and over-reaching (short-term overtraining).
Despite increasing the muscles’ ability to use fat as an energy source, there is no clear evidence to date that chronically consuming a low-carbohydrate or ketogenic diet enhances endurance performance.
‘Where do you get your protein?’ is probably the most common question every vegan gets asked. And none more so than athletes and regular exercisers. Dietary protein is needed to repair muscle cells damaged during intense exercise as well as to build new muscle proteins. But can you get enough protein from plant-based foods for optimal performance and recovery?
How much protein is considered optimal?
Regular exercise increases your protein requirement to the tune of 1.2 – 2 g per kg of body weight per day (vs 0.75g for the general population), depending on the type, intensity and duration of your activity. Studies suggest that 20 – 25g per meal is the optimal amount of protein to promote muscle protein synthesis (MPS) following resistance training. However, you may need around 40 g in your post-workout meal if you have done a whole-body resistance workout (as opposed to legs-only) or if you are over 60. Additional protein helps counteract the anabolic resistance that occurs as we get older.
How can vegan athletes get enough protein?
When you cut meat or animal products from your diet, you also eliminate a primary source of protein. Therefore, you will have to put more thought into how you will reach your protein goals using plant-based sources.
The key is to develop an understanding of amino acids, the building blocks of protein. There are 20 amino acids in the human body, but only 9 of these are essential, meaning they must come from the diet.
All plants contain all 9 essential amino acids (EAAs) although pulses, grains, nuts and seeds tend to contain relatively low concentrations of one or more EAAs. On the other hand, soya products (e.g. tofu and soya milk alternative), quinoa, chia and hemp seeds, buckwheat and amaranth contain EAAs in ratios more closely matched to the body’s needs. Provided you eat a variety of plant-based foods, any shortfall of EAAss in one food is compensated by the higher amounts found in another. For example, rice is low in lysine and high in methionine while lentils are high in lysine and low in methionine. Eating both foods will give you all nine essential amino acids.
Contrary to popular belief, plant proteins do not need to be combined in each meal in order to achieve an adequate intake of amino acids. The body has a pool of amino acids, which it draws upon and uses as required.
In other words, a vegan diet can provide enough protein as long as a variety of plant protein sources are consumed and energy intakes are adequate.
Are plant proteins as good as animal proteins for building muscle?
Until recently, plant proteins were considered less effective for building muscle than animal proteins owing to their lower amino acid concentration. Indeed, studies show that soya protein produces a smaller MPS response in the immediate (3 – 5 hour) post-exercise period than animal proteins. This is likely due to its lower leucine concentration. However, MPS following resistance exercise can last for 24 hours or more, so it is more meaningful to look at longer term muscle mass gains.
A meta-analysis of nine long-term studies (longer than six weeks) found that plant proteins are as good as animal proteins for increasing strength and muscle mass, provided you eat enough of them. The researchers found that soya and whey protein supplements produce similar gains in strength and muscle mass following resistance training. There was no difference in bench press, squat strength or total lean body mass gains between those consuming whey and those consuming soya supplements.
These results support the findings of a previous meta-analysis, which found that provided you hit a minimum threshold intake of 1.6g/ kg/ body weight, the protein source (soya vs whey) makes no difference to your strength and muscle mass gains. More recently, a study at the University of Sao Paulo and McMaster University compared gains in leg muscle mass and strength between vegans and omnivores consuming 1.6g protein/ day for 12 weeks (Hevia-Larraín et al., 2021). Researchers found no difference in gains between the groups, suggesting that plant proteins are just as effective as animal proteins for building muscle provided you consume enough of them.
Which are the best protein sources for vegan athletes?
The richest vegan sources of protein (and leucine) are soya-based foods. Firm tofu contains 13g per 100g, while tempeh (21g/ 100g) and soya mince (15g/ 100g) contain levels comparable to meat and fish. Soya products along with quinoa, buckwheat, amaranth, chia and hemp seeds are considered ‘high quality’ or ‘complete’ proteins as they contain all nine essential amino acids in ratios closely matched to the body’s needs.
Beans, lentils and peas typically contain 7 – 9g per 125g portion (or half a 400g tin), while edamame beans (young soya beans) contain 15g per 125g portion. Hummus comes in lower, at 3g per 50g portion – owing to its higher water and oil content. Nuts and seeds contain 6 – 9g per 30g portion.
You may be surprised to learn that many grains, such as pasta, bread and oats, are also valuable sources of protein. Even green vegetables such as broccoli supply a few grams. So, if you were to eat a portion of pasta (9g), beans (9g) and broccoli (4g), then you will be getting 22 g protein – the amount deemed optimal for muscle building.
If you enjoyed this article and want to find out more about food and nutrition, as well as some easy and tasty meal inspiration, then my new book, The Vegan Athlete’s Cookbook is now available from Amazon, Waterstones, Bloomsbury and other booksellers.
Exciting, healthy and tasty vegan recipes with the nutrients you need to train, recover and perform.
Whether you already live a vegan lifestyle, embrace a meat-free day each week or you simply want to try some amazing flavour combinations, The Vegan Athlete’s Cookbook will help you create easy, nutrient-packed meals to support your training goals.
With a focus on performance, every recipe has been created to provide a high level of nutrients that will fuel your body. All the main meal recipes supply at least 20g protein per serving, the optimal amount needed for muscle recovery.
Your gut microbiota has a huge impact on virtually every aspect of your physical and mental health. Now a growing body of research suggests that it also affects your performance and recovery.
What is the gut microbiota?
Your gut microbiota comprises trillions of bacteria, yeasts, fungi and viruses that live in your digestive tract, mostly in the colon. These microorganisms break down fibre and produce chemicals, namely short-chain fatty acids (SCFAs) that are needed for many vital functions in the body
Can exercise affect your gut microbiota?
Regular exercise has shown to increase microbial diversity. A 2014 study of professional rugby players found a much greater diversity of gut microorganisms in the players compared with sedentary controls.
More recently, researchers at the University of Illinois at Urbana-Champaign, US showed how previously-sedentary volunteers who undertook six weeks of endurance exercise improved the diversity of their gut microbiota. When the volunteers stopped exercising, their microbiomes reverted back to their previous state.
Exactly how exercise affects the gut microbiota isn’t clear but it is thought that exercise creates favourable conditions in the gut that allows for more diversity of gut bacteria and increased production of SCFAs. A review published in the Journal of the International Society of Sports Nutrition concluded that regular exercise has beneficial effects on the composition and diversity of the gut microbiota.
Can your gut microbiota affect performance?
At the same time, your gut microbiota may influence your performance and recovery. A review published in 2020 concluded that the variability in responses to physical activity may be explained by differences in people’s gut microbiota. The exact mechanisms are not fully understood but it is likely that those with a high diversity of gut microorganisms produce more SCFAs, and have less oxidative stress and lower inflammation, key factors that may result in enhanced performance and recovery.
A review of 33 studies with athletes concluded that the gut microbiota plays a key role in controlling oxidative stress and inflammatory responses as well as improving immunity, metabolism and energy expenditure during endurance exercise.
With better immunity, you’re less like to suffer illnesses that can hamper your training. And with less oxidative stress and lower inflammation, you will have less muscle damage and faster recovery. Additionally, the SCFAs produced by gut microorganisms help regulate energy metabolism, appetite hormones and body composition.
How can you change your gut microbiota?
You can increase the diversity of your gut microbes – and gain a performance and health advantage – by eating a plant-based diet rich in fibre, polyphenols, probiotics and prebiotics. These all provide food for your ‘good’ gut microorganisms so they can thrive. A US study showed that you can achieve significant alterations in your gut microbiota within as little as 24 hours of a dietary change.
Here are my top tips:
Eat a wide range of plant foods – Try to get as many different kinds of fruit, vegetables, whole grains, beans, lentils, nuts, and seeds in your diet as possible. Variety is key because each contains different nutrients that the gut microorganisms thrive on. The American Gut Project, a large-scale study that analysed microbiome samples from more than 10,000 people showed that people who ate 30 different plants each week had much greater microbial diversity than those who ate just ten.
Eat plenty of fibre – There are many types of fibre and the more types you eat the greater the benefit. Aim for a minimum of 30g fibre a day. Fibre promotes the growth of health-promoting gut micororganisms.
Include polyphenol-rich foods – Colourful fruit and vegetables, especially berries, as well as nuts, tea, red wine, and cocoa products are rich in polyphenols that encourage the growth of health promoting microorganisms
Include fermented foods containing probiotics – these are the live bacteria found in non-dairy yogurt, sauerkraut (fermented cabbage), miso (fermented soya bean paste), tempeh (fermented soya beans), kombucha (fermented tea) and kimchi (fermented Chinese cabbage), and will have a short-term beneficial effect on your gut microbiota (it lasts only as long as you are eating these foods regularly)
Focus on prebiotics – these are a type of dietary fibre that feed the ‘good’ microorganims in your gut. Foods rich in prebiotics include beans, lentils, chickpeas, Jerusalem artichokes, onions, garlic, asparagus, and leeks.
Avoid ultra-processed foods – They contain ingredients, such as emulsifiers, that either suppress health-promoting microorganisms or increase ‘unhealthy’ species.
Summary
In summary, your gut microbiota plays an important role in shaping your health and performance. A gut microbiota with a high diversity of microorganisms can help you perform to your full potential and promote healthy recovery. This can be achieved by consuming a plant-based diet rich in fibre, polyphenols, probiotics and prebiotics and minimising ultra-processed foods.
If you enjoyed this article and want to find out more about food and nutrition, as well as some easy and tasty meal inspiration, then my new book, The Vegan Athlete’s Cookbook is now available to pre-order
Exciting, healthy and tasty vegan recipes with the nutrients you need to train, recover and perform.
Whether you already live a vegan lifestyle, embrace a meat-free day each week or you simply want to try some amazing flavour combinations, The Vegan Athlete’s Cookbook will help you create easy, nutrient-packed meals to support your training goals.
With a focus on performance, every recipe has been created to provide a high level of nutrients that will fuel your body. All the main meal recipes supply at least 20g protein per serving, the optimal amount needed for muscle recovery.
With less than three weeks to go before the 2021 London Marathon, here are nine evidence-backed nutrition tips to help you get the most out of your marathon training.
ALWAYS EAT CARBS PRIOR TO A LONG RUN
A good rule of thumb is to eat a good source of carbohydrate with a smaller amount of protein and healthy (unsaturated) fat two to four hours before a run. This combination of macronutrients will provide sustained energy to help you through a longer run. For long runs, avoid too much fibre within 30 minutes of exercise, especially if you are prone to tummy issues.
The carbs in your pre-run meal will help maintain blood sugar levels during your run and prevent fatigue, while a small amount of protein and unsaturated fat will slow the digestion of carbs, resulting in a more sustained rise in blood sugar – exactly what you need when running. Good pre-run meals include a jacket potato with beans, cheese or tuna; rice with beans; chicken stew with couscous; or pasta with tomato sauce.
THINK ABOUT THE NIGHT BEFORE
Many runners prefer doing their long runs early in the morning, especially on the weekend. If this is you, prioritise carbs in your meals the day before to ensure you have plenty of glycogen in your muscles. Then have a small pre-run snack 30-60 minutes before you set off – good options include a banana, a handful of dried fruit, or a couple of Medjool dates. If you cannot stomach anything before your run, ensure you’re properly hydrated before you set off and plan to run for less than 90 minutes.
REFUEL AS YOU RUN
For any run or race longer than 60-90 minutes, it’s worth thinking about taking extra carbs on board while you run. This will help maintain blood glucose levels and supply a quick source of energy to your muscles, which means you’ll be able to keep up your pace for longer. Start fuelling 30-45 minutes into your run and don’t wait until you’re depleted. Aim for 15-30g of carbs every 30 minutes depending on your pace; the key is little and often. Good options that serve up 30g of carbs include one large banana, one 50g energy gel, 500ml isotonic sports drink, or two Medjool dates.
DON’T FORGET ABOUT PROTEIN
There are three main goals of nutrition recovery: rehydrate, refuel and repair. Your post-run meal needs to supply carbs to replace glycogen but also protein to repair muscle. Aim for around 20-25g of protein post-run. Milk and soya milk alternative are near-perfect recovery drinks as they not only aid rehydration but also contain carbs and good-quality proteins to promote rapid post-run recovery. Great recovery meal options include a berry, yoghurt and almond smoothie; falafel and hummus wrap; chicken and prawn paella; bean and sweet potato curry; or a lentil, chickpea and cauliflower dahl.
MAKE SURE YOU EAT ENOUGH
One of the most common mistakes I see runners make when training for a marathon is under-fuelling. Marathon training should never be seen as a way to lose weight. Running long distances places a great deal of stress on the body and doing this without adequate fuel can harm your body. A consistent mismatch between your energy intake and output will almost certainly result in chronic fatigue, frequent illnesses and injuries and poor recovery. It can cause women to lose their period, which increases the risk of bone loss and stress fractures. Prevent under-fuelling by fuelling for the work required, ensuring you eat more carbs before hard sessions, and prioritising your post-run recovery nutrition.
CARB UP BEFORE A MARATHON
Carb loading – maximising your glycogen stores – may help delay fatigue and reduce your chances of hitting the dreaded wall. You can achieve this by increasing your carbohydrate intake for the final two days as well as tapering your training. This allows the carbs that you would have burned in your long runs to get stored as glycogen in your muscles instead. Don’t overload, though – aim to keep overall calories the same by cutting fat while upping carbs. Opt for easy-to-digest carbs (e.g. potatoes, rice and pasta), aim to eat most of your carbs at breakfast and lunch and avoid too much fibre.
MAKE A FUEL PLAN
Everyone’s different so you will need to work out what works for you by practising your fuelling and hydration strategy a few times during your long runs. Simulate race-day conditions as far as possible, using the same foods and drinks and practise taking them at the frequency you plan to during the race. Making it as realistic as possible will help ensure there won’t be any surprises on the big day. You’ll also need to practise drinking on the move from cups or bottles. This may feel tricky or uncomfortable to start with but start with small amounts and gradually build up. Check in advance where feeding and drinks stations are on the route so you can plan when to refuel.
STICK TO WHAT YOU KNOW
It may sound obvious but don’t do anything new on race day. I’ve seen so many first-timers make the mistake of consuming energy gels or products for the first time during their marathon experience stomach problems. If you want to use these products, trial them during your long runs. Similarly, don’t make the mistake of eating anything different for breakfast on race day – if you normally have porridge with honey before your long runs then eat porridge with honey before your marathon.
DON’T OVER-HYDRATE
If you’ve practiced a drinking strategy in training, then you should have a good idea how much to drink. But if the temperature is higher or lower on race day then you will need to adjust your plan. Dehydration can increase fatigue, slow your pace and cause a drop in performance. Equally, drinking more than you’ve lost in sweat – over-hydration – can be just as harmful. If you feel bloated, swollen and fatigued, then you’re probably over-hydrated so should stop drinking.
If you enjoyed this article and want to find out more about food and nutrition, as well as some easy and tasty meal inspiration, then my new book, The Vegan Athlete’s Cookbook is now available to pre-order
Exciting, healthy and tasty vegan recipes with the nutrients you need to train, recover and perform.
Whether you already live a vegan lifestyle, embrace a meat-free day each week or you simply want to try some amazing flavour combinations, The Vegan Athlete’s Cookbook will help you create easy, nutrient-packed meals to support your training goals.
With a focus on performance, every recipe has been created to provide a high level of nutrients that will fuel your body. All the main meal recipes supply at least 20g protein per serving, the optimal amount needed for muscle recovery.
CBD (cannabidiol) seems to be all the rage among athletes and regular exercisers. Among other things it purports to help relieve pain, reduce muscle soreness and inflammation, improve sleep quality and ease anxiety. Approximately 4 – 6 million UK adults have tried CBD. However, research to support its use is sparse and manufacturers are not allowed to make explicit health claims for it. Here’s what you need to know about cannabidiol.
What is CBD?
CBD is one of around 120 active compounds (cannabinoids) found in the Cannabis sativa plant. CBD is produced from the hemp (as opposed the marijuana) strain of the plant, which has a very low concentration of tetrahydrocannabinol (THC), the illegal psychotropic compound. Whereas THC enables you to get ‘high’, CBD does not. However, it is mistaken to describe it as having no ‘psychoactive’ effect, because it acts on the brain and appears to impact cognitive functions. CBD is widely available in the form of oils, tinctures, capsules, sprays, lotions and gummies.
Despite this, one study of more than 500 rugby league and union players found that 26% currently or previously used CBD to provide pain relief or improve sleep quality.
How does CBD work?
It is thought that CBD works by interacting with the body’s endocannabinoid system (ECS). This is a network of receptors in your brain, peripheral tissues and immune system which is involved in regulating sleep, appetite, pain and immune responses. The body produces its own cannabinoids (endocannabinoids), that bind to CB1 and CB2 receptors and inhibit the release of certain neurotransmitters. It is plausible that CBD supplements augment the body’s own endocannabinoids.
In terms of improving sleep quality, it has been proposed that CBD inhibits adenosine re-uptake in the brain.
Is it legal?
Hemp-derived CBD is legal to buy and use in the UK provided it contains less than 0.3% THC. It is also legal for use in drug-tested sport since it was removed from the World Anti-Doping Association’s (WADA) prohibited list in 2018. However, UK Anti-Doping (UKAD) cautions against its use as it may be contaminated with THC or other prohibited cannabinoids.
A recent report by industry body, the Centre for Medicinal Cannabis, blind-tested 30 CBD products, bought on the High Street and online. It found almost half (45%) had measurable levels of THC, making them technically illegal in the UK. Only 38% of the products were within 10% of the advertised CBD content and 38% actually had less than half of the advertised CBD content. One product had 0% CBD. For this reason, athletes subject to anti-doping rules are advised to avoid it as it carries a risk of inadvertent doping.
Are there any side effects?
A 2018 report from the World Health Organisation says CBD is safe and doesn’t have the potential for addiction. Similarly, a review on the safety and side effects of CBD found it is well-tolerated although there are reports of tiredness, diarrhoea and changes in appetite. One study in mice indicated potential for liver damage and interactions with other medications.
Practical recommendations
The lack of published evidence for CBD and the risk of contamination with THC means it cannot be recommended to athletes and regular exercisers at present, particularly those who are subject to anti-doping rules. Even those products displaying a certificate of analysis cannot guarantee inadvertent doping. Another problem is the big variation in CBD concentration between products, as well as the lack of data on effective doses. Since CBD products are expensive, I recommend saving your money for now.
If you enjoyed this article and want to find out more about food and nutrition, as well as some easy and tasty meal inspiration, then my new book, The Vegan Athlete’s Cookbook is now available to pre-order
Exciting, healthy and tasty vegan recipes with the nutrients you need to train, recover and perform.
Whether you already live a vegan lifestyle, embrace a meat-free day each week or you simply want to try some amazing flavour combinations, The Vegan Athlete’s Cookbook will help you create easy, nutrient-packed meals to support your training goals.
With a focus on performance, every recipe has been created to provide a high level of nutrients that will fuel your body. All the main meal recipes supply at least 20g protein per serving, the optimal amount needed for muscle recovery.
Almost every athlete will have to take time off from training due to a sports injury at some stage. A survey of British Olympic athletes found that 43% of athletes get at least one injury per season, some suffering multiple injuries, with each injury causing on average 17 days lost to training and one competition to be missed. And when that happens you’ll want to do everything possible to speed your recovery. Here are some evidence-based nutrition recommendations to help you avoid muscle loss and unwanted weight gain during recovery from injury.
How can I avoid gaining or losing weight while injured?
To avoid unwanted weight gain when you’re not exercising, you will need to compensate for your reduced calorie output by eating less. However, this may not be as much as you imagine – during the initial recovery phase, resting metabolic rate increases by 15 – 50%, depending on the type and severity of injury, and effectively counteracts some of the drop in energy output from physical activity.
Overly restricting your food intake when injured hinders recovery, delays healing and reduces muscle protein synthesis (MPS). Similarly, a large calorie excess can also delay recovery. In practice, you will probably need to consume less than when in training but more than your sedentary baseline intake. Of course, this is easier said than done as it may take a while for your appetite to re-adjust if you are used to consuming, say, 3000 or 4000 calories. Replacing processed snacks such as cakes, biscuits and crisps with fruit, vegetables and nuts, which are more nutritious and are naturally more filling is a good place to start.
How can I minimise muscle loss?
Loss of muscle mass (atrophy) is perhaps the biggest problem during recovery from injury, especially if you have broken a limb. Even short periods (1 – 2 weeks) of muscle disuse can cause substantial loss of muscle mass and strength. Most of this is due to a decline in muscle protein synthesis (MPS) as the muscles become more resistant to the muscle-building effects of dietary protein (‘anabolic resistance’).
To minimise muscle loss, you’ll need to ensure you are consuming enough protein. Although you’re not exercising as much, your body needs additional protein for healing, and for the formation and repair of body tissues. A sub-optimal intake of protein or a drastic reduction from pre-injury levels, will impair healing and exacerbate muscle loss.
There are no official protein recommendations for recovery but studies suggest intakes in the region of 2 – 2.5g/ kg body weight/ day would help minimise muscle loss. It would also be wise to include a minimum of 20–25g at every meal and to include protein in snacks. Distributing your protein evenly across your meals and including high quality proteins that are naturally high in leucine can help mitigate anabolic resistance. These include whey protein supplements, dairy products, eggs, meat and fish. Plant protein sources include soya (tofu, soya milk alternative and tempeh), chia seeds and quinoa.
What supplements may promote recovery from injury?
Some evidence suggestscreatine supplementation may help you regain muscle faster during recovery following immobilisation. Omega-3 supplements may help to reduce inflammation and promote wound healing. Including omega-3-rich foods, such as oily fish, walnuts, rapeseed oil, chia seeds and ground flaxseed is also likely to help the healing process.
Scientists are currently investigating whether collagen supplementation can prevent or treat musculoskeletal injuries. One study showed that taking 15g of vitamin C-enriched gelatine (a food form of collagen) 1h before high-intensity exercise (skipping) increased collagen manufacture. But its early stage research and the functional benefits are not currently known.
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Under-fuelling can have a serious effect on your health and performance. The problem is many athletes and regular exercisers are eating less than they realise. What starts as a genuine desire to shed a few pounds or get fitter can easily backfire and result in under-fuelling. This means that day after day, week after week, you are not eating enough to meet your energy needs. Instead of getting fitter and faster you can end up fatigued and illness-prone. As many athletes (and here and here) have discovered, under fuelling can also cost you your performance.
Who is at risk?
Athletes most at risk include those involved in sports where havinga high power-to-weight ratio confers an advantage (such as running and cycling), weight category sports (such as boxing), and aesthetic sports (such as bodybuilding, dance and gymnastics). Young athletes can be especially vulnerable to restrictive eating and subsequent under-fuelling.
What is under-fuelling?
Under fuelling or, more accurately, low energy availability (LEA) refers to the situation in which your energy intake does not match the fuel demands of your training and basic body functions. As described in my previous article, LEA can happen either intentionally when you cut your energy intake to lose weight or unintentionally when you increase your training load without adequately increasing your food intake.
LEA underpins a condition called relative energy deficiency in sport (RED-S), which more accurately describes the clinical syndrome previously known as the female athlete triad. Although more common in females, RED-S is also something that affects male athletes.
What does energy availability mean?
Energy availability (EA) the amount of energy left over and available to the body to carry out essential functions after the energy cost of exercise has been subtracted from the energy you take in from food. In other words:
Energy Intake – Exercise Energy Expenditure = Energy Availability
For example, a 70kg athlete with 15% body fat who consumes 2500 kcal a day and burns 1000 kcal training has an energy balance of 1500 kcal. If you divide this by the athlete’s fat-free mass (FFM) (55kg) and you have an EA of 27 kcal/ kg FFM/ day. For optimal health and performance, EA should be about 45 kcal/ kg FFM/ day, although the threshold varies between individuals. Going below this level (particularly below 30 kcal/ kg/ FFM/ day) results in LEA and means you will not have enough energy available to cover basic physiologic demands. Your body will go into ‘energy-saving mode’, reducing its metabolic rate and essential functions.
What are the risks of under-fuelling?
Under-fuelling over weeks or months results in negative health and performance effects. It can impair hormonal function, immune function, gastrointestinal function, cardiovascular function and psychological function. In the longer-term, health problems such as infertility, low bone mineral density, nutrient deficiencies and disordered eating can develop (Fig 1). Even short-term energy deficits, for example during a long workout or not consuming anything following a workout, have been shown to disrupt hormones. Long-term LEA can reduce your performance and increase your risk of illness and injury (Fig 2).
How do you know if you are under-fuelling?
There are several early warning signs to look out for. These include
missed or irregular periods in females (although this can be masked by oral contraception)
lack of morning erection in males
persistent fatigue
a drop in performance or lack of expected improvement in performance
poor recovery
increased perception of effort during exercise and daily activities
recurrent illness and injuries (such as stress fractures)
changes in mood (such as feeling anxious or irritable)
reduced social interaction
problematic relationship with food and/ or training
disrupted sleep patterns.
How to prevent under-fuelling
Contrary to popular belief, lighter does not always mean faster! The weight at which you perform at your best will depend on many factors, including your age, gender, genetics and natural build. Instead of trying to get super lean, aim instead to achieve a healthy weight and body composition that allows you to perform well without compromising your health.
If you really do need to drop a few pounds, then reduce your current calorie intake byapproximately 15% on some training days, but not others. This should produce a relatively modest energy deficit of around 300 calories a day. Any more than this risks under fuelling and LEA. Calculating your personal energy requirements can be a useful starting point and there are a number of food tracking apps that you can use.
Under-fuelling can begin unintentionally so if you have recently increased training volume or if you are doing a hard block of training, you should take steps to avoid it by being more proactive in planning your food. Pay attention to your energy levels, and make a sustained, conscious effort to consume enough energy (calories). You will need to eat more on hard training days. If this proves difficult, then including some lower fibre (e.g. ‘white’ instead of wholemeal pasta) options can make this easier. Include plenty of foods rich in healthy fats, such as nuts, seeds, nut butters, avocado and olive and rapeseed oil in all your meals and snacks. These foods will help boost your energy intake without adding too much extra volume. If you find it difficult to eat larger portions, add high-energy snacks, such as nuts, nut butter on toast, and fruit and nut bars between meals.
If you suspect under-fuelling, then you will need to increase your food intake and/ or reduce your training volume. However, these two things can often be harder than they sound so consider seeking the help of a professional to get you back on track. Your GP, sports doctor, sports dietitian, or a psychologist will be able to provide assessment and advice. My previous article also provides practical advice for those with amenorrhoea.
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Expert advice on how to how to eat well and improve your performance
The sports supplements market is big business. But, according to a recent consensus statement by the International Olympic Committee, the majority of sports supplements have little evidence to back them up. At best, they are unnecessary, and, at worst harmful or prohibited. In Part 1, I looked at supplements supported by solid evidence. In this article (Part 2) I cover supplements that may be worth considering and those that have no or limited benefit.
Category 2: Supplements that may be worth considering
Cherry Juice
POSSIBLE BENEFITS: REDUCED INFLAMMATION, IMPROVED BLOOD FLOW
A study at Northumbria University found that cyclists who consumed 30 ml of Montmorency tart cherry juice concentrate twice daily for 5 days before and 3 days after a simulated 109-minute road race experienced less muscle damage and inflammation. And a meta-analysis of 10 previous studies, published earlier this year concluded that it may also enhance endurance performance when taken 1.5 hours or up to 7 days before an event. These benefits are attributed to its high content of anthocyanins, which are powerful vasodilators, antioxidants and anti-inflammatory agents.
Blackcurrant extract
POSSIBLE BENEFIT: IMPROVED BLOOD FLOW
Blackcurrant anthocyanins have similar benefits to those found cherries and may also improve recovery from exercise-induced muscle damage. A double blind study from the University of Chichester found that 7 days of supplementation with 300mg New Zealand blackcurrant extract improved 16.1km time trial performance by an average of 2.4% and increased fat oxidation by 27% during moderate-intensity cycling. However, a more recent study by the same research team found that runners who took blackcurrant extract fared no better in terms of recovery, post-exercise muscle soreness or fatigue after a half-marathon compared with those who took a placebo.
Collagen
POSSIBLE BENEFIT: ENHANCED INJURY RECOVERY
Collagen is the main protein in tendons, bones, ligaments and cartilage and scientists are currently investigating whether collagen supplementation can prevent or treat musculoskeletal injuries. A joint US- Australian study showed that taking 15g of vitamin C-enriched gelatine (a food form of collagen) 1h before high-intensity exercise (skipping) increased collagen manufacture. But its early stage research and the functional benefits, and the effects on injury recovery in elite athletes are not currently known.
Turmeric/ curcumin
POSSIBLE BENEFIT: REDUCED INFLAMMATION
Curcumin is the bioactive ingredient in turmeric root that gives the spice its distinctive yellow colour and has been shown in lab tests to have anti-inflammatory properties. A double-blind New Zealand study in 2015 showed that taking 5g curcumin a day for 2.5 days prior to and following eccentric (muscle damaging) exercise reduced subsequent pain associated with DOMS and lowered muscle damage. More research is needed to back up these findings, though.
‘Greens’ powders
POSSIBLE BENEFIT: EXTRA PLANT-DERIVED NUTRIENTS
Greens powders contain various blends of plant extracts, vitamins and minerals. Although it’s tempting to believe that the powdered form of vegetables are just as good, you’re better off eating the actual food. Powders lack the fibre and water abundant in vegetables that are so important for satiety. When it comes to vitamins and minerals, more isn’t necessarily better and – unless you eat whole foods too – you risk getting too much of one vitamin and not enough of others. There’s no published evidence that they enhance performance. However, green powders could be a useful addition to your diet if you struggle to eat sufficient fruit and vegetables.
Category 3: Supplements that have no or limited benefit
Branched chain amino acids (BCAAs)
CLAIMED BENEFIT: IMPROVED MUSCLE SYNTHESIS
Theoretically they may help prevent protein breakdown and during fasted training. But, according to a 2017 study at the universities of Exeter and Stirling, if sufficient protein is being consumed then there appears little benefit in taking BCAAs.
Cannabidiol (CBD)
CLAIMED BENEFIT: REDUCED PAIN AND INFLAMMATION
CBD is a cannabinoid produced by the cannabis plant, which some brands claim has pain relieving and anti-inflammatory benefits. These claims are supported only by anecdotal evidence. Although it is not currently a banned substance, it carries a high risk of inadvertent doping due to contamination with tetrahydrocannabinol (THC), the illegal psychoactive compound.
Nootropics
CLAIMED BENEFIT: SHARPENED MENTAL FOCUS
Nootropics, or ‘smart drugs’ are supplements that can potentially boost mental performance. They include both natural (e.g. herbal extracts) and synthetic substances. Nootropics marketed as pre-workout boosters claim to improve energy and focus. Some small studies show that some nootropic supplements can affect the brain. But there is a lack of evidence from large controlled studies to show that these supplements work and are completely safe.
DON’T ACCIDENTALLY DOPE
Supplements are the biggest cause of inadvertent doping in the UK. Unlike prescription medicines, there is no systematic regulation of supplements, which means there’s no official check on safety, quality or whether they are free from prohibited substances. British Cycling have a policy of strict liability, which means you take supplements at your own risk and cannot claim you didn’t know what you were taking. Not only could you risk failing a doping test but you also risk serious harm to your health. You can cut this risk by making sure your supplement comes from a reputable company that has strict manufacturing controls and provides a certificate to prove it has been batch tested for banned contaminants by a recognised sports anti-doping lab. Look for the Informed Sport logo on the label and cross reference the batch number on their website www.informed-choice.org/.
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Expert advice on how to how to eat well and improve your performance
The Complete Guide to Sports Nutrition, ninth edition is the definitive practical handbook for anyone wanting a performance advantage. This fully updated and revised edition includes guidance on:
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