Updated 19th April 2024

Are you experiencing exhaustion?

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Everyone has days when they feel tired, but if you’re constantly struggling with exhaustion or fatigue, it can have a significant impact on your health. 

People with exhaustion may also experience headaches, muscle soreness, problems concentrating, mood swings, and even difficulty sleeping. 

If exhaustion comes with other symptoms, it could signify a serious health condition, and you may need to discuss it with your doctor. 

At ZOE, we run the largest nutritional study of its kind, with over 15,000 participants so far. Our research shows that everyone’s body responds differently to food, and this can affect tiredness.

Our unpublished data also found that 82% of people who closely followed our personalized nutrition program for 3 months said they had more energy.

You can take a free quiz to find out what the ZOE program can do for you. 

In this article, we'll explore the reasons why you might be feeling exhausted and some lifestyle changes you can try to help you boost your energy, including how to eat the right foods for your body. 

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What are the signs of exhaustion?

While some signs of exhaustion may seem obvious, others can be hard to pinpoint. 

Aches and pains, or problems focusing, can sneak in slowly. And if you find yourself in a bad mood regularly, it can be hard to know why. 

Headaches and muscle soreness

Studies have established a strong link between fatigue and chronic migraine headaches. But the potential effects on the body go beyond that. 

Researchers are continuing to find associations between fatigue and chronic pain in other areas of the body, such as the joints and muscles. 

However, more research is needed to discover how the two are linked and whether one causes the other. 

Mood swings

Exhaustion can shorten your temper and make you more prone to feeling down. It may also make you extra sensitive to things like loud noises or being around too many people. 

Scientists studying the complex relationships between exhaustion, anxiety, and depression have found that they are distinct issues. Yet at the same time, they are often linked and are seen as interconnected. 

If you’re experiencing exhaustion, there’s a good chance you may also struggle to handle setbacks without them affecting your mood. 

Brain function

If you find it hard to focus or you’re avoiding making simple decisions, it can be a sign of exhaustion.

A review of recent studies looked at people who had experienced burnout due to the pressures of work. It found that this kind of exhaustion was linked to difficulties with attention and memory, as well as so-called executive functions, like planning and juggling different tasks. 

Problems with sleep

Although sleep seems like the thing you need most when you’re tired, some people find that feeling exhausted can actually lead to insomnia or poor quality sleep. 

That’s because the symptoms of exhaustion can increase your levels of the stress hormone cortisol, which plays an important role in sleep. Typically, your cortisol levels will drop as you approach your bedtime and begin to increase in the second half of the night to help you wake up the next day. 

Too much cortisol can make it much harder to fall asleep. This can, in turn, make your exhaustion worse. 

How to boost your energy

If you’re exhausted, there are lifestyle changes that may help.

Adding exercise to your routine and going to bed earlier — rather than sleeping for longer — can make a difference. Additionally, eating the best foods for you can be a key part of boosting your energy levels.

Eat the right foods for your body

If you regularly feel tired at the same time of day, it may have to do with the foods you’re eating

After you eat, your blood sugar rises and then drops again. Certain foods, like sugar, white bread, and other refined carbohydrates, can lead to bigger rises and bigger subsequent drops. 

This is sometimes called a blood sugar “crash” and can cause tiredness and a lack of energy, as well as other symptoms. 

However, avoiding these crashes and boosting your energy is not as simple as eating fewer processed carbs. 

Our research shows that everyone has different responses to foods. For example, some people may see large spikes in their blood sugar levels after eating bananas, while for others, their response may be more subtle. 

The bacteria and other microorganisms that live in your gut — known collectively as your gut microbiome — are also involved in your blood sugar responses to foods. 

Small studies have even suggested links between the health of your microbiome and chronic fatigue syndrome. 

ZOE’s at-home test can help you to understand your body’s individual blood sugar and blood fat responses to foods, and it will tell you the types of microbes that make up your unique microbiome. 

With the ZOE program, you get personalized recommendations to help you find the best foods for you. 

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Go to bed earlier

It’s no surprise that sleep is an important factor in your overall energy levels. However, it’s not just quantity or quality that counts. If you struggle with fatigue, try to adjust your sleep patterns. 

ZOE’s latest sleep study demonstrated that the time you turn in each night has an impact on your blood sugar control the next morning. 

People who went to bed later were more likely to experience spikes and dips in their blood sugar after eating breakfast, even if they slept in. 

As well as making you more tired, these dips can also lead to cravings for sweet foods. And, as we’ve seen, eating these can lead to more spikes and dips — so more spells of tiredness. 

Exercise more 

It may sound counterintuitive, but adding more exercise to your routine can help boost your energy. However, you don’t have to do a lot to make a difference.

In one small study, people who usually didn’t exercise, and who had been experiencing fatigue, started a 6-week exercise program. One group did moderate amounts of exercise, another did low amounts, and by the end of the study, both gave similar reports of having significantly more energy. 

If you’re feeling tired but don’t have time for a workout, you can still see some benefits from getting up and doing a short amount of exercise.

In another small study, 18 college women with long-term sleep deprivation found that a brief session of stair walking was more effective at improving their fatigue than taking caffeine supplements.  

While you’ll generally notice the effects immediately afterward, there are also long-term benefits of regular exercise when it comes to your energy levels. 

Unpublished research by ZOE found that people who exercise more have better blood sugar control, which we’ve already seen can have an impact on whether you feel tired. 

Other possible causes of exhaustion

Together with other symptoms, exhaustion could be a sign of a more serious health condition:

  • Thyroid conditions almost always cause fatigue due to changes in hormone levels. Other symptoms include increased sensitivity to temperature, weight loss or gain, muscle pain or weakness, and changes to heart rate. 

  • Anemia, due to iron deficiency, can reduce blood oxygen levels and make it harder to use energy. It can also cause generalized weakness and shortness of breath as well as pale and sallow skin. 

  • Depression can lead to fatigue and excessive sleep in many people.

Certain medications can cause drowsiness and lethargy, too. Drugs that treat allergies, depression, anxiety, and blood pressure may all leave you feeling tired.

Fatigue is also a common side effect of alcohol and other narcotic use. 


When coupled with long-term fatigue, migraine headaches, muscle soreness, mood swings, problems sleeping, and difficulty thinking can all be signs that you are suffering from exhaustion. 

Other symptoms — including sensitivity to temperature, weight loss or gain, nausea, trouble waking up, and shortness of breath — can be linked to serious health conditions. If you’re experiencing any of these alongside exhaustion, you should talk to your doctor.

If you’re regularly feeling tired during the day, try to change what you eat, focus on your sleep, and get more exercise. 

The ZOE program analyzes your blood sugar and blood fat levels, as well as your gut microbiome. Based on your individual results, you can find the best foods for your body and your long-term health.

Take our free quiz to find out more. 


10 medical reasons for feeling tired. (2021). https://www.nhs.uk/live-well/sleep-and-tiredness/10-medical-reasons-for-feeling-tired/

A randomized controlled trial of the effect of aerobic exercise training on feelings of energy and fatigue in sedentary young adults with persistent fatigue. Psychotherapy and Psychosomatics. (2008). https://www.karger.com/Article/Abstract/116610 

Fatigue in substance abuse disorders. Revue Médicale Suisse. (2015). https://pubmed.ncbi.nlm.nih.gov/26072600/ 

Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions. Diabetologia. (2022). https://link.springer.com/article/10.1007/s00125-021-05608-y 

Iron-deficiency anemia. (n.d.). https://www.hematology.org/education/patients/anemia/iron-deficiency

Job burnout and cognitive functioning: a systematic review. An International Journal of Work, Health & Organisations. (2014). https://www.tandfonline.com/doi/abs/10.1080/02678373.2014.909545

Migraine headaches in Chronic Fatigue Syndrome (CFS): comparison of two prospective cross-sectional studies. BMC Neurology. (2011). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058027/ 

Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome. Microbiome. (2016). https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-016-0171-4 

Replication of cortisol circadian rhythm: new advances in hydrocortisone replacement therapy. Therapeutic Advances in Endocrinol Metabolism. (2010). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475279/

Stair walking is more energizing than low dose caffeine in sleep deprived young women. Physiology & Behavior. (2017). https://www.sciencedirect.com/science/article/abs/pii/S0031938416310666 

The challenges of chronic pain and fatigue. Clinical Medicine. (2021). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850224/ 

The relationship between burnout, depression, and anxiety: a systematic review and meta-analysis. Frontiers in Psychology. (2019). https://www.frontiersin.org/articles/10.3389/fpsyg.2019.00284/full 

Thyroid 101: hypothyroidism and hyperthyroidism. (2020). https://healthblog.uofmhealth.org/health-management/thyroid-101-hypothyroidism-and-hyperthyroidism

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