He did not describe himself as stressed. He said he was simply tired.

A clinical story about chronic stress, fatigue and metabolic regulation

Case confidentiality statement
This article is inspired by a clinical pattern encountered in practice. The name, personal circumstances, chronology and other identifying details have been changed, omitted or combined to protect client confidentiality. It should not be interpreted as the complete history or treatment record of any identifiable individual.

When Daniel first came to the clinic, he did not describe himself as stressed. He said he was simply tired. For years, he had managed a demanding workload, financial pressures and responsibilities at home. He was accustomed to solving problems, meeting deadlines and carrying on regardless of how he felt. Even when life became difficult, he rarely stopped.

“I’ve always been able to push through,” he explained. “But now it feels as though my body has stopped cooperating.”

His tiredness began before he even got out of bed. He could sleep through the night and still wake feeling as though he had barely rested. Getting dressed and preparing for the day required more effort than it once had. By late morning, his concentration was already declining. After lunch, the fatigue became overwhelming. Instead of feeling replenished by food, he often felt as though someone had switched off his energy. His eyelids became heavy, his thinking slowed and he struggled to continue working. Whenever possible, he would lie down and sleep.

The nap helped temporarily, but by early evening he frequently wanted to sleep again.

He had also developed an almost constant desire for sugar. Biscuits, chocolate and sweet drinks gave him a brief lift, allowing him to continue for another hour or two. The improvement never lasted. His energy would fall again, and the search for something sweet would begin once more.

Over time, other changes appeared. His eyesight seemed to be deteriorating. His eyes looked puffy underneath, particularly in the morning. He experienced persistent discomfort across his lower back. He caught colds and flu-like infections more easily than he once had and appeared to take longer to recover.

Perhaps most worrying to him was the change in his thinking. He struggled to remember names and details that would once have come easily. He would enter a room and forget why he was there. During conversations, he sometimes found it difficult to retrieve the word he wanted.

“I don’t feel as sharp as I used to,” he said. “It feels as though my brain is working through fog.”

At first glance, these symptoms might seem unrelated:

• waking exhausted;
• needing to sleep during the day and again in the evening;
• severe fatigue after meals;
• persistent sugar cravings;
• slower thinking and poor concentration;
• changes in eyesight;
• recurrent colds and flu-like illnesses;
• puffiness beneath the eyes;
• lower-back discomfort.

Clinical practice, however, asks us to look beyond each symptom in isolation.

The history behind the fatigue

Daniel’s exhaustion had not appeared suddenly. For many years, his body had been responding to ongoing psychological and practical pressure. During a short-lived stressful event, the stress response is protective. Cortisol and other stress hormones help make fuel available so that the brain and muscles can respond to an immediate challenge. Glucocorticoids such as cortisol can increase glucose production by the liver and reduce glucose uptake and utilisation in tissues such as skeletal muscle and adipose tissue. In an acute emergency, this helps preserve fuel for the brain and other immediate demands.[1,2]

Once the challenge has passed, the body should be able to move back towards rest, restoration and metabolic balance. Daniel’s difficulty was that the challenge never seemed to pass. There was always another deadline, another responsibility or another problem requiring his attention. His body repeatedly received the message that energy needed to remain immediately available. Over time, prolonged activation of stress pathways and increased cortisol exposure can contribute to adverse metabolic effects, including impaired insulin sensitivity, particularly when combined with insufficient sleep, physical inactivity, visceral adiposity, dietary factors or an underlying susceptibility.[1,2]

Insulin is the hormone that helps cells take up and use glucose. When tissues become less responsive to insulin, the pancreas may initially compensate by producing more of it.

This compensation can sometimes maintain blood glucose within the reference range for a period, despite increasing metabolic strain beneath the surface.

In Daniel’s case, the combination of prolonged stress, disrupted recovery, persistent sugar cravings and marked fatigue after meals raised a clinical suspicion that insulin and blood-glucose regulation might have become part of the wider picture. It did not, by itself, confirm insulin resistance.

Post-meal fatigue can have several possible causes. Insulin resistance, prediabetes and diabetes must be assessed through appropriate medical history, examination and testing rather than diagnosed from symptoms alone.

The stress–sugar cycle

Daniel had become caught in a cycle that many exhausted people will recognise. Stress increased the demand for readily available energy. Fatigue made him crave sugar. Sugar gave him a temporary lift. The lift was followed by another decline. The decline created another craving.

Because he felt so tired, he moved less. Reduced movement meant that his skeletal muscles had fewer opportunities to use glucose through physical activity.

His low energy also made it harder to plan and prepare balanced meals. Quick, sweet foods became the easiest way to keep functioning. Meanwhile, the pressures contributing to his stress response remained unresolved.

This was not simply a failure of willpower. His body was searching for fuel in the fastest way it knew. The problem was that the strategy providing short-term relief was no longer creating long-term stability.

Why he felt tired and alert at the same time

One of the confusing features of chronic stress is that a person can feel profoundly exhausted while still finding it difficult to settle fully. Daniel needed to sleep during the day, but his sleep did not always leave him restored. His body was fatigued, yet part of his stress-response system appeared to remain watchful.

This can create the experience often described as being “tired but wired”: physically depleted, mentally restless and unable to move smoothly between activity and recovery. The body becomes increasingly practised at responding to demand, while the transition back into rest and repair becomes less successful.

Why he was catching more colds

Daniel had also noticed that he seemed to catch every cold circulating around him. The immune system does not operate separately from the nervous, endocrine and metabolic systems. Large analyses of human studies have found that chronic psychological stress is associated with changes in immune function, while prospective research has linked psychological stress with increased susceptibility to upper-respiratory infections.[3,4]

This does not mean that stress alone explains every cold or flu-like illness. Exposure to viruses, sleep, nutrition, existing health conditions, vaccination status and many other factors influence whether someone becomes unwell. However, recurrent illness formed another part of Daniel’s wider clinical picture: a body experiencing persistent demand without sufficient restoration.

What about his eyesight and mental fog?

Changes in eyesight and cognitive function should never simply be dismissed as consequences of stress. Fatigue, disrupted sleep and fluctuating energy availability can affect concentration and mental performance. However, worsening vision, persistent cognitive changes and severe daytime sleepiness may also have other medical explanations.

Fatigue and blurred vision are among the symptoms that can occur with diabetes, although many people with prediabetes or type 2 diabetes have few or no noticeable symptoms.[5,6] The presence of these symptoms does not prove that diabetes is present. It means that appropriate assessment is important. Depending on the individual presentation, investigation of persistent fatigue may include consideration of:

• fasting glucose and HbA1c;
• blood pressure and cardiovascular risk;
• full blood count and iron status;
• thyroid function;
• vitamin B12, folate or vitamin D where clinically appropriate;
• kidney and liver function;
• sleep quality and possible sleep apnoea;
• medication or alcohol effects;
• infection, inflammatory illness or other medical conditions.

An eye examination may also be necessary when eyesight is changing. The purpose of identifying a clinical pattern is not to force every symptom into one explanation. It is to recognise possible connections while remaining alert to conditions that require separate investigation.

The clinical turning point

Daniel initially wanted something that would give him more energy. But stimulating an already overworked system was not the answer. The goal was not to help him push harder. It was to understand why his energy was no longer being regulated and restored effectively.

His clinical plan therefore focused on reducing the repeated metabolic and stress-related demands being placed on his body. This included reviewing meal composition and timing, reducing reliance on sugar, supporting more stable glucose regulation, improving sleep and recovery, introducing appropriate physical movement and addressing the long-standing pressures that kept his stress response activated.

Medical assessment and relevant investigations were also important, particularly because of his severe fatigue, post-meal symptoms, eyesight changes and cognitive concerns.

The work was gradual. His body had spent years adapting to chronic demand. It could not be expected to reorganise itself in a few days. The first positive change was not that he suddenly felt full of energy. It was that he could eat lunch without feeling that he had to lie down immediately afterwards. His cravings became less urgent. His energy began to feel more predictable. He could think for longer without losing focus, and he gradually became less dependent on naps to complete the day.

These changes represented the progress of one individual clinical pattern. They do not predict how another person will respond or establish that the same approach is appropriate for everyone.

The wider clinical lesson

Chronic stress is not confined to the mind. Through interactions among cortisol, sleep, appetite, behaviour, glucose availability and insulin action, long-term stress may contribute to a wider disturbance of metabolic regulation.[1,2]

Fatigue is sometimes described as though the body has simply run out of energy. In some cases, however, the deeper problem may involve how energy is being mobilised, distributed, used and restored.

Fuel may be repeatedly made available in response to stress, while the tissues responsible for using that fuel become less responsive. Sugar may provide temporary rescue while contributing to a pattern of fluctuating energy. Persistent fatigue may then reduce movement, impair food choices and make restorative behaviour more difficult. The clinical question is therefore not only:

“Why is this person tired?”

It is also:

“What has happened to the body’s ability to regulate energy, respond to food and recover from demand?”

Daniel’s body had not suddenly failed him. It had adapted for years to an environment of persistent pressure. His symptoms emerged when those adaptations could no longer maintain stability without cost.

Recovery began when the focus shifted away from forcing more performance and towards restoring the conditions required for metabolic balance, immune resilience and genuine physiological recovery.

The body can survive prolonged stress by continually making energy available. But health also depends on being able to stop mobilising energy and begin restoring it.

Medical disclaimer

This article is provided for general education and does not constitute medical advice, diagnosis or treatment. The case narrative has been adapted and anonymised and should not be used to diagnose insulin resistance, diabetes, a cortisol disorder, immune dysfunction or any other condition.

Symptoms such as persistent or severe fatigue, worsening eyesight, cognitive changes, recurrent infections, excessive thirst, frequent urination, unexplained weight change or marked sleepiness should be discussed with a qualified medical professional. Insulin resistance and diabetes require appropriate clinical assessment and testing.

Sudden changes in vision, severe confusion, fainting, breathing difficulty or rapidly worsening symptoms require urgent medical attention.

Herbal medicines, nutritional supplements and significant dietary changes may not be appropriate for everyone and can interact with medicines or existing health conditions. Treatment should be individualised and, where appropriate, coordinated with the person’s medical practitioner.

References

1. Mazgelytė E, Karčiauskaitė D. Cortisol in metabolic syndrome. Advances in Clinical Chemistry. 2024;123:129–156. doi: 10.1016/bs.acc.2024.06.008.
2. Kuo T, McQueen A, Chen T-C, Wang J-C. Regulation of glucose homeostasis by glucocorticoids. Advances in Experimental Medicine and Biology. 2015;872:99–126. doi: 10.1007/978-1-4939-2895-8_5.
3. Segerstrom SC, Miller GE. Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry. Psychological Bulletin. 2004;130(4):601–630. doi: 10.1037/0033-2909.130.4.601.
4. Pedersen AF, Zachariae R, Bovbjerg DH. Influence of psychological stress on upper respiratory infection: a meta-analysis of prospective studies. Psychosomatic Medicine. 2010;72(8):823–832. doi: 10.1097/PSY.0b013e3181f1d003.
5. Centers for Disease Control and Prevention. Symptoms of Diabetes. Updated 15 May 2024.
6. National Health Service. Symptoms of Type 2 Diabetes and How It Is Diagnosed. Reviewed 10 February 2025.
7. National Health Service. Tiredness and Fatigue. Reviewed 2 June 2023.