We all feel tired from time to time. But if you’re waking up exhausted, struggling through the day, or feeling mentally foggy — even after a good night’s sleep — it might be more than just a passing slump.
Persistent tiredness, or fatigue, is one of the most common health concerns.
It can affect your mood, concentration, physical stamina, and even how much joy you feel day to day.
But the good news?
Many causes of fatigue are linked to lifestyle — and there are simple, evidence-based ways to start feeling more energised.
Not all sleep is equal. Even if you’re in bed for 7–9 hours, your body may not be getting the deep, restorative rest it needs.
The NHS emphasises that quality sleep supports energy, mood, and immunity.
Magnesium — a calming mineral found in leafy greens, seeds, and nuts — may help improve sleep by supporting the production of melatonin and calming the nervous system.
A systematic review in Nutrients found that magnesium intake is linked to better sleep quality, particularly in older adults [1].
Even slight dehydration — just 1–2% of body weight — can leave you feeling sluggish, foggy, or headachy. It can also reduce your ability to concentrate or stay alert.
A study in the British Journal of Nutrition found that adults who were mildly dehydrated reported greater fatigue and reduced alertness compared to those who were well hydrated [2].
✅ Tip: Aim for 6–8 glasses (1.5–2 litres) of fluids per day, and more if you’re active or in hot weather.
Your body relies on key nutrients to generate and sustain energy. When levels are even slightly low, tiredness can creep in.
Iron – needed for oxygen transport in the blood. Low iron is a common cause of fatigue, especially in women.
Vitamin B12 – supports red blood cell formation and nervous system health.
Magnesium – involved in energy production and stress regulation.
Omega‑3s – support brain health and help manage inflammation.
A 2020 review in Nutrients found that suboptimal intake of these micronutrients is widespread and may contribute to fatigue and low mood [3].
Meals high in refined carbohydrates — like white bread, biscuits, or sugary cereals — can cause your blood sugar to spike, then crash. That crash often comes with fatigue, brain fog, and cravings.
High-fibre foods help by slowing the absorption of sugar into the bloodstream, which prevents sharp spikes and dips in energy.
A randomised trial published in the Journal of the International Society of Sports Nutrition found that people following a low‑glycaemic load diet had significantly lower fatigue scores compared to those eating high‑GI foods [4a].
Another study in npj Digital Medicine found that both high and low blood glucose swings were linked to dips in mental clarity and energy [4b].
✅ Tip: Build meals around fibre, protein, and healthy fats. Think oats with seeds and berries, or lentil salad with olive oil and avocado.
That “tired but wired” feeling is often a sign your stress system is overactivated. Chronic stress raises cortisol levels, which over time can disrupt sleep, reduce immune function, and sap your energy.
A review in Psychosomatic Medicine confirmed that high stress is closely linked with fatigue — even when people report getting enough sleep [5].
✅ Tip: Take short breaks throughout the day, practise deep breathing, or spend a few quiet minutes outdoors. These small pauses help reset your stress response.
Daylight plays a key role in setting your internal body clock (circadian rhythm). Without enough morning light, your energy rhythms can drift — making you feel groggier during the day and more alert at night.
A 2023 study in Sleep Science Advances found that exposure to morning light significantly improved sleep and daytime alertness in indoor workers [6].
✅ Tip: Try to spend 10–30 minutes outside each morning, even if it’s cloudy. If that’s not possible, sit near a window to get some natural light exposure.
It might seem counterintuitive, but the less you move, the more tired you may feel. While it’s natural to want to rest when your energy is low, being inactive can actually make things worse — reducing circulation and slowing your metabolism.
Gentle movement boosts oxygen flow, lifts mood, and helps your cells (especially mitochondria) produce energy more effectively.
A 2023 meta-analysis in Scientific Reports found that moderate exercise significantly reduced fatigue in adults with chronic conditions [7]. Earlier research confirmed that even low-to-moderate intensity movement improves energy and reduces fatigue over time [8].
✅ Tip: Start with a 10-minute walk or gentle stretch. Even small bursts of movement throughout the day can lift your energy.
In the UK, vitamin D levels drop significantly during the colder months due to lack of sunlight. Low vitamin D has been linked to tiredness, muscle aches, and low mood.
A 2023 review in Nutrients found that vitamin D supplementation significantly reduced fatigue, particularly in people who were deficient [9].
✅ Tip: The NHS recommends everyone takes a 10 µg (400 IU) vitamin D supplement daily between October and March — or year-round if you’re indoors most of the time.
Caffeine — found in tea, coffee, energy drinks, and some supplements — can offer a quick lift in alertness and help with focus. In moderation, it can be a helpful tool.
But when used too often, or too late in the day, it can quietly undermine your energy in the long run.
A study published in Nature Communications Biology found that consuming 200 mg of caffeine in the evening significantly disrupted the brain’s ability to recover during sleep — reducing the amount of deep, slow-wave sleep your body depends on to restore energy [10].
It’s also easy to build up a tolerance — meaning the same amount of caffeine has less effect over time. And if you miss your usual dose, withdrawal symptoms like headaches, irritability, and sluggishness can creep in.
✅ Tip: Enjoy caffeine mindfully. Try to have your last cup by mid-afternoon to protect your sleep. If you're still feeling tired despite multiple cups a day, it may be worth gradually reducing your intake — and supporting your energy through better sleep, hydration, and nutrition instead.
Sleep: Stick to a routine, limit screens, try magnesium-rich foods at night
Hydration: Sip water regularly throughout the day
Nutrition: Eat balanced meals with protein, fibre, and healthy fats
Daylight: Get 10–30 mins of morning light exposure
Movement: Walk or stretch every 1–2 hours
Stress support: Take mindful breaks, go outside, or try breathing exercises
Caffeine: Cut off caffeine by mid-afternoon to protect sleep
Supplement if needed: Vitamin D, omega‑3, magnesium, iron or B12.
Fatigue is your body’s way of asking for support — not just more sleep, but deeper balance.
By focusing on gentle movement, nutrition, light exposure, stress relief, hydration, and mindful caffeine use, you can begin to restore your energy naturally.
You don’t have to change everything at once — even one small shift, like adding a morning walk or cutting back on caffeine, can make a real difference. Start with one or two changes this week — your future self will thank you.
1. How soon might I notice a difference?
Many people notice improvement in energy within 1–2 weeks of better hydration, daylight exposure, and light movement. Nutrient-related improvements (like iron or vitamin D) may take several weeks.
2. How do I know if I’m deficient in something?
Your GP can run blood tests to check iron, B12, and vitamin D levels if you’re feeling persistently tired.
3. Should I exercise even if I feel exhausted?
Yes — gently. Start with light stretching or a short walk. Movement boosts energy over time, even if it feels hard at first.
4. Can I take vitamin D all year round?
Yes, especially if you spend most of your time indoors or cover your skin when outside. The NHS recommends 10 µg (400 IU) daily.
5. What if I rely heavily on caffeine to function?
That’s often a sign your body needs more rest, sleep, or support. Try reducing caffeine gradually while focusing on underlying causes of fatigue.
6. When should I see a doctor?
If fatigue lasts more than four weeks, gets worse, or comes with other symptoms (like breathlessness, low mood, or pain), it’s a good idea to speak with your GP to rule out any underlying issues.
Hormonal changes — such as those during perimenopause or an underactive thyroid — can also contribute to ongoing tiredness, even if you’re otherwise healthy. Your GP can help check for these and suggest the right support.
This article is for general information only and is not intended to treat or diagnose medical conditions. If in doubt please check with your GP first.
References:
Rondanelli M et al. Magnesium and sleep quality. Nutrients. 2021;13(3):712.
Benton D, Young HA. Do small differences in hydration status affect mood and cognitive function? Br J Nutr. 2011;106(10):1535–1543.
Gröber U et al. Micronutrients and fatigue: A review. Nutrients. 2020;12(1):281.
Barton C et al. Effects of low vs high glycaemic load meals on energy and fatigue. J Int Soc Sports Nutr. 2012;9:26.
Hall H et al. Cognitive performance is associated with glucose excursions: evidence from continuous glucose monitoring. npj Digital Medicine. 2021;4:25.
Wingenfeld K et al. Chronic stress, fatigue, and cognition. Psychosom Med. 2007;69(9):876–884.
Blume C et al. Effects of morning light exposure on sleep and alertness in indoor workers. Sleep Sci Adv. 2023.
Chou L et al. Effects of exercise on fatigue in chronic conditions. Sci Rep. 2023;13:10512.
Puhr J et al. Vitamin D supplementation and fatigue reduction. Nutrients. 2023;15:2861.
Weibel J et al. Evening caffeine impairs slow-wave sleep and sleep homeostasis. Nat Commun Biol. 2017;8:110.
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