Skip to content

Sports Performance Blood Testing Guide

A great way to improve your performance and get results is to understand what's going on inside your body. It's how top athletes fine-tune and make gains.

Shop sports performance tests Dr Sam Rodgers - Chief Medical Officer

Reviewed by Dr Sam Rodgers

6th December 2019


Blood tests for sports performance

Chapter 1

Blood tests for sports performance

Strong and injury free running

Chapter 2

Strong and injury free running

Training and sports nutrition

Chapter 3

Training and sports nutrition

The female athlete triad

Chapter 4

The female athlete triad

Case study - Anna Bonniface

Chapter 5

Case study - Anna Bonniface

Knowledge is power -  blood testing for body builders

Chapter 6

Knowledge is power - blood testing for body builders

How to boost testosterone naturally

Chapter 7

How to boost testosterone naturally

Blood tests for sports performance

Chapter 1

Blood tests for sports performance

Sports performance isn’t just about what you look like on the outside. Find out how checking your inner health can help you perform at your best.

Most people who embark on a fitness regime measure their progress with a stopwatch, a tape measure or a mirror. Although your physical appearance can be a good indicator of your general health, at Medichecks we’re far more interested in finding out and helping you to understand what is happening on the inside – usually improvements in personal bests are matched by improved biomarkers in the blood.

How can you improve your performance?

For sports people of all levels, sometimes things don’t go according to plan. You can feel tired, lack motivation and struggle to recover after injury. You may well be over-supplementing and throwing out the delicate balance of hormones and nutrients your body needs to function at its best. You might be over-training and not giving your body the chance to recover causing chronic stress and inflammation. Without knowing what’s going on in your body, it can be very difficult to understand why you’re not performing at your best.

What can a health check tell you about your performance?

Monitoring baseline markers throughout training cycles enables necessary adaptations to training, recovery and nutrition to be put in place to keep you on track to perform. Here are 5 key areas that are important to monitor to make sure you perform at your best and keep yourself healthy in the process.


Hormones, especially testosterone and its precursor DHEA, are important for building muscle and burning fat as well as for mood and motivation. Low levels might explain why you’re finding it difficult to lose those extra pounds and gain that six-pack you’re aiming for. Exercise is perceived by the body as a form of stress and it stimulates the release of cortisol. Long-term high levels of cortisol can lead to the breakdown of muscle and will interfere with muscle development. Endurance athletes are commonly low in testosterone so doing more strength work can raise testosterone levels.

Having a greater understanding of your hormone levels can help to optimise your sporting performance.

Thyroid function

Your thyroid is the gland which governs your metabolism. Too low and you’re often lacking the energy to climb the stairs let alone run a 10k, too high and you’re jittery and nervous and finding it difficult to sleep. An underactive thyroid could be the reason why, despite your diet and exercise programme, you struggle to lose those unwanted pounds.


C-reactive protein (CRP), is a protein used as a marker of inflammation in the body. High-intensity sports training causes inflammation and raises CRP levels – and if you don’t recover properly, CRP levels can remain elevated. The good news is that exercise with proper recovery can help to decrease CRP in the blood. As an athlete it’s important to monitor levels of CRP to make sure you are correctly balancing exercise and recovery.

Iron status

Iron is a mineral vital for transporting oxygen from the blood to the tissues which is crucial for every type of athlete – using oxygen efficiently is very important in athletic training and muscle building. Unsurprisingly, low levels of iron can affect sporting performance – not only will you feel tired, but your body will struggle to get the vital oxygen it needs, causing you to feel breathless and dizzy. On the other hand, too much iron in the blood can increase inflammation, raise cholesterol and impact cardiovascular health – so as an athlete it is important to monitor iron levels.

Vitamins and minerals

Nutrition is a cornerstone of athletic performance and is just as important as training plans and broader recovery strategies. There are several vitamins and minerals that are important to monitor when training including magnesium, vitamin D and B12. Magnesium is an important mineral needed for proper muscle, nerve and enzyme function. Vitamin B12 is important for the production of red blood cells, for metabolism and for the normal functioning of the nervous system, while vitamin D is important for athletes as it relates to overall health, bone density, innate immunity and muscle wasting. Many of us in the UK are vitamin D deficient – with symptoms including muscle weakness, mood swings and fatigue. To train and perform optimally, it is important to monitor and track your levels of these vitamins and minerals.

Strong and injury free running

Chapter 2

Strong and injury free running

What are the pitfalls of too much training? Learn about the role of catabolic and anabolic hormones in training and recovery.

To improve as an athlete, from beginner to elite level, you need to stress your body. As you recover, rest and adapt the stress you create through training allows you to get fitter and stronger. When they think about stress in the context of sport, athletes mostly focus on muscles and joints….and normally associate it with injury or being out of shape. This is understandable, the body of your racing car is what you see first and we want that paintwork shiny and undented. However, what is under the bonnet – your engine, oil and fuel – is more relevant to athletic performance.

For endurance athletes, adrenal health is a critical consideration in deciding what training to do, when to build up that training and when to cut back. Here we look at some basic considerations to get a rounded sense of your health and performance.

Keeping it on a level

As you exercise your body releases hormones in order to keep itself in balance – a process called homeostasis. Hormonal changes occur which allow you to meet your increased energy needs, balance your hydration and manage your stress reactions in order to perform. After exercise, your hormones work to restore your energy levels and hydration and assist proteins to repair and rebuild damaged muscle fibres and tissues. There are many hormones involved when you train and race but let’s look at a few key ones;

Stress hormones – key stress hormones cortisol and epinephrine help increase energy levels, circulation, respiration and blood sugar levels when we exercise.

Sex hormones – oestrogen, progesterone and testosterone are all involved with growth metabolism, reproductive health, strength and endurance.

On a simplistic level testosterone is an anabolic hormone – it helps to build muscle, produce red blood cells and increase aerobic metabolism in muscles. Cortisol is a catabolic hormone – catabolism is the breaking down of complex molecules (in food) into simpler ones that can be used for energy in the body. Cortisol works antagonistically with testosterone, inhibiting protein synthesis and blocking anabolic signalling.

Running on flat – overtraining syndrome (OTS)

When chronically elevated, cortisol actively breaks muscle down and makes you more prone to infection, leading to fatigue and failure to make progress. For both endurance and strength trainer athletes chronically elevated cortisol can be a marker of overtraining which is where the body does not sufficiently recover after exercise. This in turn leads to physiological stress, emotional change and a decline in performance.

If ignored, overtraining syndrome (OTS) can be a very serious condition which can take months and even years to recover from. Don’t think you need to be running 120 miles a week either – our busy and stressful work, social and family lives can mirror many of the effects of overtraining and the combination of training and life factors makes this a real consideration for thousands of everyday people.

Check under the bonnet

Coaches working with athletes use regular blood tests to monitor levels of cortisol, testosterone and oestrogen over periods of time to establish a baseline for individual athletes and check for significant changes, particularly in hard training cycles. In addition, they check for sustained markers of inflammation namely cytokines and C-reactive protein (CRP). CRP is a plasma protein produced by the liver which changes in response to acute and sustained stress and infection.

The warning signs

In addition to blood tests it’s important to be mindful of other key warning signs of damaging hormonal changes:

Lack of progression: Despite increasing the quality and/or quantity of your training, your progression slows or reverses. You’re working harder in sessions that have felt easy in the past.

Injuries and niggles: Consistently getting injuries or persistent niggles that don’t clear or keep reappearing.

Muscle fatigue and slow recovery: Really struggling to recover from your harder sessions and feeling flat regularly.

Mood swings and sensitivity: Finding yourself regularly irritable and moody.

Loss of motivation: Simply no longer enjoying your training, seeing running as a ‘chore’ and fearing your hard sessions as well as a loss of focus and determination in sessions and races.

Weight loss or gain: Overtraining increases the likelihood of rapid and hard-to-explain weight fluctuations.

Cravings: It’s common to find yourself craving sugar and processed foods to help give you an energy boost not produced by your adrenal system.

Tiredness: Constant, or periods of, extreme tiredness. A decreased ability to achieve a deep sleep phase, often indicated by an increase in movement during sleep is another sign.

Illness: Upper respiratory infections are a very common OTS indicator.

Loss of libido: Overtraining causes a reduction in anabolic hormones, which can result in reduced sex drive.

Blood deficiencies: Aside from checking your hormones blood tests can also reveal OTS markers such as a drop in ferritin (a protein that stores iron), B12 and magnesium.

In order to get a good balance of catabolic and anabolic hormones we recommend a few key steps;

1. Have a plan:

A sensible, structured and balanced training plan that takes gives you a planned and sustainable progression is really important. A good plan will see you move through different types of training at different times of the year, balance rest and recovery with harder sessions and ensure you have lighter weeks.

2. Be ready to adapt:

Keep an eye on the warning signs and your blood markers and be prepared to step off your plan and take extra rest or recovery sessions if needed.

3. Write it down:

Tracking both your volumes and intensity of training but also your blood results and motivation is key to monitoring your body and adaptation over time. A good training diary should include all this data – review it on a weekly basis.

4. Take the hard with the easy:

Alternate hard and easy sessions to ensure your body rebuilds at a cellular level – and make sure you include at least one full rest day each week. Include cutback weeks, where intensity and volume are reduced, every third or fourth week. Schedule periods of total rest after key races such as a marathon. A heart rate monitor and activity tracker can be a great tool in helping you understand the ‘load factor’ of your sessions and just how long your body needs before it’s ready for another hard session.

5: Life priorities:

Look at all the external forces around your training – work and social life pressures, emotional upheaval and relationship stress will massively impact on your ability to recover. Manage these where you can but if you can’t you might need to accept that your training may need to be scaled back for a period.

6: Fuel your recovery:

A balanced diet packed full of micronutrients from varied healthy sources will help keep your body ticking over. Ensure a good intake of key vitamins and minerals, including iron, vitamin C, magnesium, B vitamins and zinc.

7: Sleep yourself fit:

Anabolic hormones are released during your deep sleep cycles and there’s a direct link between regular poor sleep and increased risk of OTS in athletes. Banish phones, tablets, laptops and TVs from the bedroom and avoid caffeine, sugar and alcohol late at night.

Training and sports nutrition

Chapter 3

Training and sports nutrition

Fuel is a cornerstone for any athlete. Find out what to eat and when for maximum gains and learn how iron deficiency can affect your race performance.

Nutrition is a cornerstone of athletic performance and with the professional athletes, nutrition is just as important as training plans and broader recovery strategies. Getting your nutrition spot on before your training sessions will not only give you more energy to hit the speed or intensity you want but will also help kick-start your recovery after your sessions.

Here are our top tips to guide your nutrition:

Mixing it up:

Varying your food and your diet can really help boost your intake of vitamins and minerals. Many of us tend towards eating the same foods with small changes day in, day out. Mix it up, get creative in the kitchen and think about adding to your foods to increase nutrient density.

Carbohydrate clever:

Eat wholesome wholegrain carbohydrate sources such as rye bread, sweet potatoes and buckwheat for more sustained energy. Try and avoid excessively large portions of ‘refined carbohydrate’ such as cakes and sugary cereals as these won’t provide the same sustained energy and have less nutrient density.

Protein rich:

Eating protein regularly is critical to recovery as our body doesn't store protein like it does carbohydrates and fat. It's important to eat a good variety of protein sources daily. Of course, this can include lean meat and dairy but there are plenty of vegetarian sources if you look to nuts, seeds, pulses and pseudo-cereals like quinoa or teff.

Keep it flowing:

Carry a bottle of water wherever you go and ensure you keep filling it up aiming for at least 2-3 litres a day. If it’s hot, and to be sure of avoiding dehydration, consider sipping from water containing an electrolyte tablet to retain pre-exercise vitamin and mineral balance.

Fasted training:

Training ‘fasted’ pre-breakfast can be useful for runners training for longer distance events such as a marathon as it can help to stimulate stored fat metabolization. However, these runs should be easy and relaxed up to a maximum of 75-90 minutes. Regularly completing harder sessions pre-breakfast will limit your ability to recover and adapt.

Pre-run fuelling:

Meal timing is especially important in activities such as running. A good rule of thumb is to limit your pre-run meal to about 300-400 calories eaten approximately 3 hours before training. A smaller 200-calorie meal such as a wholemeal bagel could be a great option between 1 and 2 hours before running.

Energy packed:

Your pre-training meal should contain foods that are high in carbohydrate, low in fat, with moderate amounts of protein. It’s worth being careful with high fibre foods in this meal as they can cause digestive discomfort when you run. Bananas, homemade energy bars, wholegrain bagels or oatcakes are great options.

Plan your day:

If you plan on running in the evening, plan your food intake accordingly to allow for a healthy mid-morning and mid-afternoon snack. This could include whole grain rice cakes with nut butter, a handful of dried mango or a banana to ensure you’ve got enough energy to fuel your run. However, try not to overeat during the day as this might leave you feeling lethargic, sluggish and may cause stomach issues whilst running later on.

Finding a kick:

Some runners find that a coffee or other source of caffeine gives them a boost when training, but for others it can cause higher heart rates and stomach discomfort. Make sure you try different options in training before a key race. In a similar vein, sports specific products such as energy bars, drinks or gels have a role at the right time in or around hard sessions or racing but you should be getting the majority of your energy and nutrients from your day to day diet.

How to make it all work

Get organised: The main reason for runners arriving at sessions tired or under-fuelled is lack of planning. Think about your day, plan your meals and don’t just wing it. Treat your body like the racing car it is.

Have the option: It’s very hard to have a varied diet packed full of healthy foods if you haven’t bought them in the first place! Check out some of our ideas below and aim to plan your weekly shopping in advance.

Link your training to your nutrition: It sounds obvious but on days when you have a harder session in the evening or a long run you’re going to need a bit more energy. On these days put extra focus on ensuring a good level of carbohydrate intake.

Get creative: Scratch cooking doesn’t always take as much time as we think. High-quality meals, cooked from scratch ARE possible within 30-40 minutes and you are much more likely to increase your nutrient density if you enjoy time in the kitchen!

Healthy Breakfast Ideas

  • Oatmeal, raw honey, berries, cinnamon and mixed seeds
  • Amaranth or buckwheat pancakes with fruit and yoghurt
  • Smoothies – vegetable, fruits, nuts, seeds and dairy based
  • Nut Butter (almond), banana, and chia seed rye toast
  • Berry and yogurt smoothie
  • Savoury oatmeal with an egg
  • Quinoa fruit salad
  • Teff grain, fruit and flaxseed porridge
  • Tahini on spelt toast with egg
  • Sprouted grain wholemeal toast with seed butter and chopped banana
  • Bircher muesli with apple

Healthy Lunch Ideas

  • Sprouted tofu salad with cauliflower mash
  • Split pea soup with teff bread with cashew cheese
  • Tofu, cashew and salad wholemeal wraps
  • Black beans, brown rice and salad
  • Quinoa, feta and walnut salad
  • Sweet potato, cottage cheese and salad
  • Hummus, beetroot and salad pitta breads
  • Edamame bean hummus on rye toast and salad
  • Buckwheat pancakes (make the night before and re-heat in the microwave) with avocado, crème fresh and salad

Healthy Dinner Ideas

  • Miso-roasted aubergine steaks with sweet potato
  • Butternut squash, fennel rocket risotto with mozzarella
  • Cauliflower, paneer with couscous
  • Ratatouille with lentils, goat’s cheese and polenta chips
  • Moroccan chickpea stew with faro grain or quinoa
  • Adzuki beans with millet pasta and tomato and vegetable pasta sauce
  • Bulgar wheat with mixed bean chilli and vegetables
  • Chili made with beans and whole grains like bulgur
  • Whole-grain pasta and soy, lentils, quinoa and mixed salad
  • Mashed potatoes and marinated tofu with roasted vegetables
  • Refried beans and corn tortillas with salad

Are micronutrients important to athletes?

If you take part in regular sports, when looking at dietary intake and fuelling, it’s common practice to focus on energy intake and “macro” nutrients – carbohydrate, protein and fat. These are certainly important and a major driving force behind how we perform but what about our micronutrients? Their name may infer that they are less important, however despite the fact we need them in smaller amounts compared to macronutrients, micronutrients are vital to our performance and health.

What are micronutrients?

Micronutrients are better known as vitamins and minerals. They are only needed in minute amounts but the body cannot usually synthesise them itself and therefore they must be consumed through the diet. They are needed in almost every process in the body, such as immune function, bone health, blood clotting, energy production and fluid balance to name a few.

Ensuring we consume adequate amounts of vitamins and minerals on a daily basis is key to good health and performance. The micronutrient content of food varies so you need a wide variety of food to meet your requirements. Marginal deficiencies may have little effect on the sedentary person but could have significant effect on an athlete. It is also possible that regular, intense exercise may result in an increase in micronutrient losses from the body making it important for athletes to meet their micronutrient intake requirement.

How do you ensure you are getting enough vitamins and minerals?

People who exercise regularly generally have an increased overall energy requirement. This means most athletes have a higher dietary intake during the day to fuel this increased energy expenditure and most will meet their overall macro and micronutrient needs. However, this is not the case for all. If you skip meals or don’t have a good food group balance throughout the day you are at risk of not getting enough vitamins and minerals. If you ensure you are having a varied 5-8 portions of fruit and vegetables a day (in a variety of different colours) and plenty of whole grains with each meal, you will be well on your way to getting what you need.

Do I need supplements?

If you are eating a well-balanced, varied diet there is no reason why you should need a supplement. If you have a Medichecks blood test and you find you have low levels of a particular vitamin or mineral, initially you may want to try and increase those levels with a food first approach (unless otherwise advised by a health care professional). You may be advised to take a specific supplement to address that deficiency. If you are wanting to take a multivitamin (as some athletes do as a safety blanket), ensure it does not supply above 100% RDA levels of any particular nutrient. There is no point in exceeding these levels and it could even be dangerous. Excess water-soluble vitamins will simply be excreted but fat-soluble vitamins (A, D, E and K) can build up and in rare cases cause toxic levels in the body.

In simple terms, if you meet your energy needs during the day with a balanced, varied diet you should meet your body’s requirements for micronutrients. People who have to be more aware are those that struggle to meet their daily energy needs or those who follow restricted diets which might mean that their micronutrient levels are low. Having blood tests throughout the year at specific phases of your training cycles will ensure you are in balance and that you are providing your body with what it needs to perform and recover well.

How important is iron to the endurance athlete?

We have often mentioned the importance of healthy iron levels to runners and its relevance to aiding performance. Too often runners concentrate on the training itself rather than the surrounding factors that could be contributing to their running having hit a ceiling or even gone backwards.

Why is iron important for endurance athletes?

Iron is essential for the transportation of oxygen to aerobically exercising muscles. It is an important element of haemoglobin, the oxygen carrying protein in red blood cells, and is also an essential constituent in myoglobin which transports oxygen within the muscle cells to the mitochondria, the energy producer of the muscle cell. Within cells, iron is an important component in the enzymes and proteins involved in the breakdown of glycogen and other fuel sources to produce energy.

How would I know if my iron levels are low?

The main symptoms of iron deficiency in athletes are fatigue and poor or reduced performance. You may notice your training times are slightly slower than you would expect. If the iron deficiency is not treated it can lead to anaemia. Anaemia is a condition that arises when there are a low number of red blood cells or if there isn’t enough haemoglobin within the red blood cells. Symptoms of anaemia include extreme fatigue, lethargy, feeling faint, pale skin and excessive shortness of breath on exertion.

Both men and women can be deficient in iron, but female runners are at particular risk of depleting their iron stores as their iron requirements are higher. Blood lost through menstruation needs to be replaced and iron is required for new red blood cell production. Endurance exercise by itself stimulates red blood cell production and the iron requirements go up accordingly. Low dietary iron intake is the most common cause of iron deficiency, so a focus on quality of food is of the greatest importance. Vegetarians and those who eat little red meat are particularly at risk of having low iron levels. Iron rich foods include red meat, turkey meat, leafy green vegetables, lentils and chickpeas.

Other common causes of iron deficiency in runners include coeliac disease, foot strike haemolysis where red blood cells travelling through the vessels on soles of the foot get squashed with each foot strike, altitude / hypoxic tent use and inappropriate anti-inflammatory use.

We would recommend all runners with fatigue or reduced performance consider taking a Medichecks Iron Deficiency Blood Test blood test to see whether low iron levels are to blame for reduced performance. This check looks at your ability to store and transport iron as well as the actual level of iron in your blood.

If I have low iron levels can they be improved?

Although iron deficiency can be treated through taking supplements, the starting place must always be through dietary review and ensuring you are getting enough iron intake through the food you eat. The body absorbs two to three times more iron from animal sources than from plants and the inclusion of vitamin C with meals helps with absorption of iron. Some of the best animal sources of iron include:

  • Lean beef
  • Eggs
  • Tuna
  • Chicken
  • Turkey

Vegetarians are at greater risk of iron deficiency due to the lower absorption rates from plant-based sources of iron but some of the best sources of iron are:

  • Beans and lentils
  • Tofu
  • Cashews
  • Dark green leafy vegetables such as spinach
  • Whole-grain and enriched breads

Typically, an athlete with iron deficiency but without anaemia, (and with no other cause for fatigue) will start to feel better within 2 - 3 weeks of taking regular iron supplements but this varies depending on how low the iron levels are to begin with and how well the person can absorb iron. Taking vitamin C alongside an iron supplement helps absorption and some iron supplements such as ferrograd C have vitamin C in the same tablet. Be careful to avoid ‘slow release’ iron preparations as your body absorbs iron from the first part of the gut. Caffeine, dairy products and calcium supplements can inhibit iron absorption so iron supplements should be taken 1-2 hours either side of these. Iron absorption can also be reduced immediately after a run, so time your supplementation or dietary intake away from training sessions.

The best way to prevent iron deficiency is to make sure you have adequate iron rich foods in your diet as outlined above. Ideally, monitor and track your iron levels with an Iron Deficiency Blood Test every 4 - 6 months to make sure you are providing your body with what it needs.

The female athlete triad

Chapter 4

The female athlete triad

Why are female athletes at risk of menstrual problems, osteoporosis and low energy? Read on to learn more about the female athlete triad.

Women are, unfortunately, more prone to performance inhibitors than men. It’s already known that many women could be turning up to races with low levels of iron; a study[1] of female runners at the London marathon showed that heavy menstrual bleeding was affecting more than a third of female athletes. Menstrual bleeding is linked to both iron deficiency and negative performance.

What is the female athlete triad?

A healthy female athlete has a good balance between energy availability, bone health and menstrual function. The female athlete triad is a condition seen when this balance falls apart. It is most commonly seen in sports where there is an emphasis on low body weight, such as endurance sports, gymnastics, ballet and rowing[2]. It has three components:

  • Low energy availability – with or without disordered eating
  • Menstrual dysfunction – irregular or absent periods
  • Low bone density

Although it is called a triad, these components are all inter-related and you don’t need to have all three at the same time.

Let’s break these down in more detail and then see how blood tests might be useful:

Low Energy Availability

Essentially your outflow (energy expenditure) exceeds your intake (calories consumed). This can result in hypothalamic, gastro-intestinal and immune dysfunction. In the past this was often attributed to eating disorders which restrict calorie intake to maintain a certain weight, but we now know that lack of proper nutrition or knowledge of proper nutrition can inadvertently lead to this too[3].

Menstrual Dysfunction

Athletes may notice a change in their menstrual cycle, ranging from irregular periods to irregular bleeding during the cycle. Absent periods in the female athlete triad is usually the result of hypothalamic dysfunction which leads to low levels of oestrogen, which in turn can negatively impact bone density.

Low Bone Density and Osteoporosis

Having poor nutrition and/or irregular or absent periods can lead to decreased bone density. This can cause weakness and an increased risk of bone fractures (such as stress fractures in the runner).

Blood tests will check your hormone levels and nutrition status (in particular calcium, iron and vitamin D). If there is something out of balance then it can be addressed before they lead to more serious problems.

Track and improve

Track and improve

See how changes in your diet and training affect your bloodwork and trend changes over time. Its a great tool for monitoring what works for you. 

Case study - Anna Bonniface

Chapter 5

Case study - Anna Bonniface

How Anna Bonniface used blood tests to help her recover from energy deficiency to a season of new personal bests.

Anna Boniface was the first non-elite woman to cross the finish line at the London Marathon in 2017. She is currently recovering from Relative Energy Deficiency in Sport (RED-S) and is gradually returning to full training. Thanks to a Medichecks blood test, Anna is able to monitor her recovery. Tracking her baseline biomarkers has helped guide her medical management, training and nutrition to ensure she is as robust as possible before transitioning back into competition.

Here we talk to Anna about how blood testing is important in sports training.

1. Why is it important for endurance athletes to have regular health checks?

For endurance athletes, there's a fine line between training hard enough to get fitter and faster whilst maintaining health. Once that line is crossed illness and injury are likely to follow. It’s difficult for an athlete to know exactly when they have crossed that line until it’s too late.

Pre-season health checks are essential for athletes to maximise their health before tough training blocks. Baseline markers can be monitored throughout training cycles and necessary adaptations to training, recovery and nutrition can quickly be put in place to keep the athlete on track to perform.

2. Has your health check given you a valuable insight into your inner health?

I’m currently getting back to full training following a stress fracture as a consequence of Relative Energy Deficiency in Sport (RED-S). My latest health check has shown that I am healthy which is reassuring. Most importantly, it provides key markers of recovery from RED-S – for example, female sex hormones, bone profile, leptin and IGF-1. These have been monitored closely by my doctors over the last few months. It helps piece the puzzle together to guide my medical management, training and nutrition.

3. Was there anything unexpected about your results? If so, will you be changing anything to try and change/improve this?

I was quite surprised by my liver function which showed raised liver enzymes. This is common after strenuous exercise, however, I didn’t perceive my training to be particularly taxing at the time. It’s highlighted that my training is causing more stress than I perceived. My body is clearly working harder than normal to recover after sessions. This has given me the vital information that I need to make the necessary changes after training sessions to ensure I recover better.

Knowledge is power -  blood testing for body builders

Chapter 6

Knowledge is power - blood testing for body builders

How we can help you reach your ultimate goals and ensure all those long hours in the gym are delivering the results you deserve.

For bodybuilders, getting bigger, body composition and improving performance are the ultimate goals. To reach these goals, many spend hard-earned money and hours in the gym to be the best they can be. But if hormones are out of balance, or blood chemistry is showing inflammation or injury, no matter how hard you train you won’t be able to perform at your best. When training your inner health is just as important, if not more so, than how you look on the outside.

Why is blood testing beneficial?

Monitoring important blood markers can provide answers to common training questions and give you the knowledge you need to improve performance and stay healthy at the same time.

1. Are you performing at your best?

Hormones in the body play a critical role in strength training. Testosterone is a hormonal driver of muscle growth, responsible for the development of male physical characteristics, muscle mass, strength and fat distribution, whereas the catabolic hormone cortisol (often called the ‘stress hormone’) breaks down muscle, suppresses the immune system and enhances fat storage at the expense of protein and muscle.

2. Are you recovering properly after training?

Training hard puts the body under a lot of stress and it’s very important to give your body enough time to recover and rebuild. Creatine kinase (CK) is a muscle enzyme which signifies muscle cell damage and can indicate if muscle damage is not being repaired. Those who train often are also at risk of chronic low-level inflammation, which can impact your performance negatively. C-reactive protein (CRP) is an inflammation marker used to assess whether there is inflammation in the body and high levels can indicate inadequate recovery or overtraining.

3. Is your diet providing the necessary nutrients for energy and optimal performance?

Nutrition is a key component of fat loss and muscle building and many people who train monitor their diet very closely and restrict their calorie intake in order to help improve their physique. It is very important to fuel the body with important vitamins and minerals – becoming deficient in essential vitamins or minerals causes breakdown of the metabolic pathway that produces optimum efficiency and performance. Because of this, it is important to monitor levels of key nutritional markers like iron, vitamin D, active B12 and folate. Proteins are the building blocks for repairing muscle tissue and a high protein diet is important in preserving muscle when training. Too much protein, however, can cause kidney damage and because of this, monitoring kidney function is also important.

Blood testing for IPED users

One group of people who should pay extra attention to their inner health are those who use image and performance enhancing drugs (IPEDs) to boost their performance gains. Many men and women use anabolic steroids to make gains quickly but without knowing or understanding the risks – it’s easy to be blind to the damage you can do to your heart, liver, hormone balance and future fertility if you are unaware of the impact of IPED use on your body. The only way to truly know if you are causing serious harm to your body before it is too late is by measuring your blood markers.

Taking IPEDs and anabolic steroids (anabolic-androgenic steroids (AAS)) can have a significant impact on your health as well as your hormone balance. Making sure that you are monitoring your health and hormones, and taking action if you can see that your results are becoming unhealthy is an important part of reducing the harmful effects of AAS use.

How can anabolic steroids affect my health?

Red blood cells: taking anabolic steroids can cause you to produce more red blood cells than normal making your blood thicker and more prone to clotting. This raises your risk of heart attack and stroke.

Liver function: liver inflammation is commonly seen in AAS users, especially if steroids are taken orally. Inflammation causes liver enzymes to leak into the blood where they can be measured. Steroid use can cause liver damage even before your enzymes are elevated.

Kidney function: although there may be no direct effect on the kidneys, elevated blood pressure (which is commonly seen with IPED use) can cause kidney damage. The combination of steroid use and high protein intake can also put pressure on kidney function.

Cholesterol: taking steroids can increase your LDL (bad) cholesterol and markedly reduce your HDL (protective) cholesterol. This increases your risk of cardiovascular disease.

Hormones: depending on whether you are on or off cycle, your testosterone levels can fluctuate wildly. It is extremely common for steroid users to have supra-normal levels of testosterone, even above the range that many laboratories will test for. Other hormones which are also affected by IPED use include oestradiol, prolactin, FSH and LH. Your hormones can affect not only your physical appearance, but also your mood, libido and your fertility.

Our range of Sports Hormone blood tests are specifically designed to give IPED users these insights and provide a special focus on the areas of your health that can be most affected by steroid use. Our doctors are experienced in understanding the risks and can help highlight any areas you need to be concerned about.

Take the ultimate test!

Take the ultimate test!

The ultimate test for athletes of every type and every level who are looking to transform their bodies through exercise and nutrition.

How to boost testosterone naturally

Chapter 7

How to boost testosterone naturally

Testosterone is essential for building muscle. Find out how you can improve your levels naturally.

Testosterone is the quintessential male hormone – responsible for the classical masculine features including increased musculature, facial hair, deep voice and sexual energy/libido.

From our mid-20s, levels of testosterone can start to decrease in males and a large part of this decline is down to deteriorating lifestyle. As we get older our commitments increase and often our stress levels go up alongside them. This can contribute to worsening diet and we generally have less time for exercise and sleep. Each of these lifestyle factors can have a negative effect on testosterone production and as one deteriorates, it makes it more difficult to maintain the others.

It takes discipline and motivation but with these four simple steps below which help boost testosterone levels naturally, you can reverse poor lifestyle choices and begin working towards a healthier and happier life.

Ways to boost testosterone naturally:

1. Move like you were meant to

Exercise and movement of any kind are essential for a long and healthy life and this is how we as humans evolved. Hunting, farming and manual labour have kept us moving in the past and it is only in recent times that levels of physical activity have dropped dramatically. This is devastating for testosterone levels and health in general.

Any exercise boosts testosterone levels in all age groups [4,5,6] and on top of this physical activity will build muscle, improve cardiovascular health and help to maintain joint mobility. If you are overweight then shedding some excess fat will also help to boost your testosterone [7]. If you are totally sedentary then you may already be caught in a negative spiral and this can be tough to break out of. The key is consistency and just getting started. Commit to doing something 3 times a week, to begin with – even for just 15 minutes. It can be a body weight circuit in your living room or a 15-minute walk around the block. If you are a more advanced trainer then regular weight training is the best way to boost testosterone levels [8].

2. Eat well and fuel your body and mind

Eating a balanced diet made up largely of whole, single ingredient foods is healthy in itself, but including all of the main macronutrients (carbohydrates, fats and protein) can contribute to healthy testosterone levels [9]. Chronic over- or under-eating or extreme dieting can all be bad for your testosterone levels [7, 10, 11].

As well as the main macronutrients, eating a wide variety of vegetables will ensure that you get sufficient vitamins and minerals to support testosterone production. Vitamin D, in particular, is essential for testosterone production [12] and as well as food, the main source of vitamin D is sunlight. Supplements can fill gaps in lifestyle and will give a boost to these essential vitamins and minerals – zinc being another that may be essential when it comes to normal levels of testosterone [13, 14].

Eating well fuels physical activity and won’t leave you feeling sluggish and lacking in motivation. The best place to start with nutrition is to try and get some form of protein and vegetables with each meal. For breakfast, this may be eggs along with some spinach. Lunch can be a tuna or chicken salad and snacks can include beef jerky, protein shakes with cucumber or carrot sticks.

3. Think and be happy

Managing stress, optimising mood and laughing often will all improve levels of naturally produced testosterone and allow the body and mind to thrive. This is easier said than done, but persistent stress and abnormally high levels of cortisol (the stress hormone) will cause testosterone levels to fall. [15,16] On top of this, high stress can cause us to make poor food choices [17] which will in turn cause increased body weight which will also negatively affect testosterone levels.

Meditation and time management are both powerful tools to manage stress and mood. Clarifying tasks, limiting the use of email and prioritising to do lists will make workloads more manageable. Meditation is also hugely underutilised, and you can start simply by stopping each day for 3-5 minutes to count breaths. There are many meditation apps available out there to guide you through this. All these techniques can help to calm the mind, gain perspective and reduce the perception of stress.

4. Sleep, rest, recuperate and grow

Adequate sleep is essential for many reasons and prioritising those 8 hours is extremely important for health. Getting less than the required amount of sleep each night will cause testosterone levels to drop [18,19,20] and in the modern age of smartphones and 24-hour accessibility, this isn’t uncommon. As with exercise, diet and mindset, sleep works in synergy and a bad night’s sleep can make you more likely to eat poorly, make it more difficult to cope with stress and make motivation for exercise more difficult.

The easiest and most accessible trick for getting a good night’s sleep in the modern world is simply to leave your smartphone outside of your bedroom at night. Apart from the blue light that the screen emits (even in night mode), you have the mental stimulation of social media and potential stress that a late-night email can cause (when you can’t do anything about it).

Boost your levels

Here are 4 simple steps that you can implement today that will boost your testosterone production and get you started on that upward spiral towards a healthy and happy life.

It’s worth noting that there are a number of medical conditions that can cause low testosterone levels and although lifestyle interventions can help in many cases, medical advice may be required. If you are suffering symptoms that you are concerned about or that don’t improve with committed lifestyle change then we would recommend seeking medical advice – a Medichecks testosterone check could be the first step in that process.


[1] Bruinvels G, Burden R, Brown N, Richards T, Pedlar C.The Prevalence and Impact of Heavy Menstrual Bleeding (Menorrhagia) in Elite and Non-Elite Athletes

[2] Noel Pollock, Claire Grogan, Mark Perry, Charles Pedlar, Karl Cooke, Dylan Morrissey, and Lygeri Dimitriou. Bone-Mineral Density and Other Features of the Female Athlete Triad in Elite Endurance Runners: A Longitudinal and Cross-Sectional Observational Study. International Journal of Sport Nutrition and Exercise Metabolism. 418-426, 2010, Vol. 20.

[3] For section:7. Loveless, Meredith B. Female athlete triad. Current Opinions in Obstetrics and Gynecology. 301-305, 2017, Vol. 29.


















Sports performance testing FAQs

Sports performance testing FAQs
How do I know the tests are accurate?

We only use laboratories which have been accredited by UKAS, the UK's accreditation service. This means that they are subject to the same stringent review procedures as an NHS laboratory.

Who will interpret my results?

One of our team of qualified doctors will interpret your results working to guidelines established by our specialist sports doctor and sports nutrition experts. 

How often should I test?

How frequently you test will depend on your goals and your training progress. Typically athletes use our tests before and after their pre-season training and then before, during and after a competitive event or bout of intense training. However, testing can be done at any time, especially if you want to track your general health as your fitness improves. 

Do you share my results with my doctor?

No, we offer a completely confidential service and won't share your results with anyone unless you ask us to. We've made it easy for you to save or print  a PDF of your results if you want to share them with your coach, doctor or nutritionist. 

Should I tell you if I'm supplementing?

We encourage you to tell us as much as you can before you have your test so that we can interpret your results accurately. This is particularly important if you are taking any performance enhancing drugs (PEDs) or any other medication that might impact your results. The more you tell us, the more tailored our advice can be.