If you feel lethargic even after a full night's sleep, the cause might be surprising. Experts explain why your get-up-and-go has gone and what to do about it.
Open the Window
The air you breathe could be an issue. “Close the door, shut the window, add a partner and a heater, and by 3am a typical bedroom sits at 1,500 to 2,500 parts per million of carbon dioxide,” says Dr Jemma King, author of Sleep First: Sleep Smarter, Think Sharper, Feel Better. “Research shows that above 1,000 ppm sleep efficiency drops, deep sleep reduces and salivary cortisol rises on waking. You’re sleeping, but your nervous system is mildly activated all night.” The fix is easy: open a window – even 2cm will do, according to King.
Low Creatine Stores
Creatine isn't just for bodybuilders. Energy is a molecule called adenosine triphosphate (ATP), produced by mitochondria. As you age, you have fewer mitochondria, so your body struggles to produce enough ATP. Creatine helps. “When creatine is combined with phosphagen, you get phosphocreatine, which regenerates ATP,” says Justin Roberts, professor of nutritional physiology at Anglia Ruskin University. Research shows benefits for regular exercisers, women, vegans and vegetarians. Supplementing can improve mental fatigue and reduce fatigue during exercise. In three separate studies, people taking 5g daily showed improved mood and cognitive function after a poor night’s sleep, slept longer, and experienced improved sleep quality. Look for micronised creatine monohydrate and take 3-5g daily for two to four weeks. Cycle creatine: take it for six weeks, then off for two to four weeks, and repeat.
Not Enough Outdoors
“Emerging evidence suggests that exposure to daylight improves our sleep and blood sugar control,” says Dr Brendan Gabriel, whose research at the University of Aberdeen focuses on metabolic biochemistry. It’s down to circadian rhythms. “We have a body clock in nearly every cell in our body,” says Gabriel. “One of the most important is the brain’s suprachiasmatic nucleus, which is most responsive to daylight. Getting exposure to outdoor daylight helps our body distinguish between day and night, which can improve sleep quality.”
Eat More Fibre
A massive 96% of people in the UK don’t meet daily fibre recommendations of at least 30g. A fibre-rich meal can slow the release of sugar into your bloodstream, giving longer lasting, steadier energy, says Dr Emily Leeming, research fellow at King’s College London and author of Fibre Power: Transform Your Energy and Feel Amazing. She suggests adding “the BGBGs to our diets – beans, greens, berries, grains and seeds – and nuts. Make those the foundation of your meal, then add other things.”
Sleep Without Rest
Getting eight hours sleep but still exhausted? “We live in a world that equates our worth with productivity,” says Zahabiyah Yamasaki, author of Protect Your Energy. She believes we need to stop rushing and start to “move at a slower pace, be intentional about commitments, and choose presence over productivity. That might mean closing your eyes rather than reaching for your phone, or sitting quietly looking out the window.” So nap, listen to a podcast, stretch, read, sit in nature, turn down a plan, cuddle your pet.
Sworn Off Smoothies and Fruit Juice
A lack of polyphenols could be to blame. “These antioxidants give pigment to fruits and vegetables – the deep purple of an aubergine, the redness of a strawberry,” says Leeming. We get most from tea and coffee, but dark chocolate, black beans, herbs and spices are concentrated sources. Research shows polyphenol supplements help with oxygen and nutrient delivery to the brain, improving reaction time and mental fatigue. A small study gave people a 400ml smoothie containing blueberry, strawberry, raspberry and blackberry, or a placebo. The berry smoothie people maintained accuracy and response times throughout the day. “150ml of fruit juice is a good source of polyphenols and is one of your five a day.”
Brain Dump
While you sleep, your brain works. Dr Jemma King provides an analogy: events during the day get documented and stacked on the desk of your personal librarian, who works through the night deciding what to keep and discard. Sometimes the boss needs to decide, and you’ll be woken at 3am with a burning thought. Help your midnight librarian by spending a few minutes in the early evening creating a list of what you’ll address tomorrow. “Be sure to add times,” says King. “For example: call Sammy’s teachers at 10.30am; call my tax accountant at 11.15am.”
Eating Too Late
Ideally clear your plate by 7.30pm, especially on steak night. “Protein – particularly big chunks of meat – takes four to six hours to leave the stomach,” says King. “Fat slows it further, while digestion raises core body temperature and draws blood toward the gut, pushing against the nocturnal cooling trend needed for deep sleep.” Eating within three hours of bedtime decreases sleep quality. Eat heavier protein and fat at lunchtime, and build evening meals around veggies, lighter protein such as fish, chicken or tofu, and plant-based carbohydrates.
Sluggish Bowel
“There is two-way communication between your gut and your brain via the vagus nerve, and 80-90% of that communication goes in the direction of gut to brain,” says Leeming. “If things are sluggish, that can make you feel lethargic because your gut is communicating back to your brain that things are not optimal.” According to one study, eat two kiwis a day (skins optional – the research was done without). “There are different types of fibre, and the particular type found in kiwis helps to draw water in to soften the stool and move it through.”
Too Focused on Protein
The UK market for protein is expected to be worth £643m by 2031. But sacrificing carbs for more protein could be detrimental. As sports dietitian and personal trainer Kerri Major says: “If this puts carb intake too low for someone’s activity levels, it can impact energy.” As a general rule, for a steady energy releasing meal, half your plate should be colourful veggies, a quarter carbs and a quarter protein, alongside healthy fats.
Air Your Bed
“Mite droppings, fragranced laundry powder and synthetic fibres can all trigger low-grade inflammatory responses, producing nocturnal congestion, itching and microarousals you don’t consciously remember,” says King. “People with house dust mite allergies are far likelier to report insomnia.” Wash bedding weekly using fragrance-free detergent, put dust mite covers on mattress and pillows, and air your bed for 10 minutes in the morning.
Sitting Too Much
From an evolutionary perspective, “long hours of being sedentary sends a message that something is wrong,” says King. “One theory suggests that in order to conserve energy to fight potential sickness and to promote sleeping to heal, our brains will make us feel sleepy, despite not actually being ill.” Every 30 minutes, stand and move for two minutes. “A 10-minute walk after lunch lowers postprandial glucose and supports afternoon energy.”
Need a Blood Test
Has your GP ruled out iron or B12 deficiency, or thyroid problems, asks Dr Linia Patel, dietitian and author of Food for Menopause? Iron deficiency produces “a heavy, physical exhaustion and breathlessness on exertion, heart palpitations, pale skin and that frustrating inability to get through the day despite adequate sleep. It can also trigger restless legs, disrupting sleep further.” B12 deficiency fatigue “feels more neurological, so brain fog, poor concentration, low mood, tingling in the hands or feet, and a deep, bone-level weariness.” Thyroid problems cause tiredness. “An underactive thyroid brings sluggishness, weight gain and feeling cold; an overactive one can cause anxious, wired exhaustion.” Request a blood test from your GP.
