Energy: what you need to know

One in five of us have low energy levels at any one time. Get the lowdown on what reduces your vitality – and how to restore it

Written by Charlotte Haigh on March 8, 2019 Reviewed by Amanda Hamilton on March 14, 2019

Feeling wiped out? It’s normal to have ‘off’ days when you feel too tired to do anything more than what’s essential. But if this happens often, and gets in the way of your daily life, it’s time to take steps to lift your energy levels.

What is energy?

Energy is both your physical ability for activity, and a sense of strength and vitality.¹ It’s also a source of fuel – carbohydrates, protein and fat in our diets provide us with the energy to grow, keep warm, stay active and survive.² Our main energy sources are: Carbohydrates – the body’s preferred source of energy. Carbohydrates are broken down into glucose that fuels everything we do, from breathing to physical activity.³ Fats and protein – if you don’t eat enough carbs, your body will first use fat and then protein for fuel. However, these aren’t the most efficient energy sources. Using protein for energy means there’s less available for it’s main role; repairing and maintaining muscles, and other body tissues.⁴ Some diets, such as the Ketogenic Diet, are designed to optimise burning fat for fuel. But side-effects can include bad breath and a build-up of ketones in the body (acids created by fat digestion) that may be harmful.⁵

What is low energy?

We all feel tired occasionally but low energy, also known as fatigue, is more than just drowsiness – it’s feeling tired all the time. Symptoms include:⁶

• physical and mental exhaustion
• lack of motivation

One in five of us feel low in energy at any one time, while one in 10 have long-term fatigue, according to the Royal College of Psychiatrists.⁷ Low energy affects women more than men, and is more common in the very young and the elderly.⁸

 What causes low energy?

There are some common causes of low energy levels, including:^9-13

• poor diet – foods that score high on the glycaemic index, like white bread and cakes, can trigger fluctuations in your blood sugar, making you feel tired
• sleep problems – adults need between seven and nine hours of sleep a night to feel fully refreshed, according to The Sleep Council
• stress – high stress levels are linked to feelings of fatigue, and can interfere with your quality sleep, too
• lack of exercise – inactivity makes it harder to get quality sleep
• certain health conditions, including depression, arthritis and anaemia
• too much caffeine or alcohol

How to lift your energy levels

Try these tips to help restore your vitality: 1. Get some sunshine – our skin makes vitamin D from sunlight but low levels of the nutrient are linked to fatigue, according to a 2013 study from Newcastle University. It’s thought that vitamin D enhances the activity of mitochondria, the ‘batteries’ inside our cells.¹⁴ During our British winters, or if you don’t get outside much, the government advises everyone to take a vitamin D supplement. 2. Stay active – it may sound counterintuitive when you’re tired, but exercise works. A 2008 study in the journal Psychotherapy and Psychosomatics found just six weeks of gentle exercise improved energy levels in sedentary adults with unexplained long-term fatigue. The researchers suggested that exercise ‘wakes up’ the nervous system, reducing tiredness.¹⁵ 3. Eat energy-boosting foods – nutritious fuel is essential to beat low energy levels. Choose low-glycaemic index foods such as wholegrains, vegetables and legumes that release glucose more slowly, and can help keep you going for longer.¹⁶ Plan your meals and snacks ahead of time too, so you can make healthy choices even when you’re busy or stressed. 4. Get enough B-vitamins – B-vits are needed by the enzymes that break down the food we eat and turn it into energy.¹⁷ The B vitamins are found in a range of foods, including wholegrains, eggs, legumes and vegetables, so it’s important to eat a varied diet.¹⁸ If you think you’re not getting enough, consider taking a vitamin B complex.  5. Drink plenty of fluids - a 2011 US study found that even mild dehydration increased feelings of fatigue during exercise.¹⁹ The NHS advises drinking six to eight glasses of fluid a day – not necessarily all water – to stay hydrated.²⁰

When to see your GP

It’s normal to feel tired at times, when you’re working long hours or have a new baby, for example. But unexplained tiredness can sometimes indicate a health condition, such as anaemia or an underactive thyroid, so see your GP who may carry out some tests.²¹  Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies. Sources 1. Collins Dictionary Online. Energy 2. British Nutrition Foundation. What is energy? 3. NHS. The truth about carbs 4. As above 5. The Association of UK Dietitians. Top 5 worst celeb diets to avoid in 2018 6. Markus MacGill. Medical News Today. Tiredness and fatigue 7. Royal College of Psychiatrists. Tiredness 8. As above 9. As Source 6 10. Harvard T.H.Chan School of Public health. Carbohydrates and blood sugar 11. The Sleep Council. How much sleep do we need? 12. Kocalevent RD, et al. Determinants of fatigue and stress 13. Jon Johnson. Medical News Today. How to tell if stress is affecting your sleep 14. Sinha A, et al. Improving the vitamin D status of vitamin D deficient adults is associated with improved mitochondrial oxidative function in skeletal muscle 15. Tara Parker-Pope. The New York Times. The Cure for Exhaustion? More Exercise 16. Netdoctor. Carbohydrates 17. Laquale KM. B-complex vitamins’ role in energy release 18. NHS. B vitamins and folic acid 19. Ganio MS, et al. Mild dehydration impairs cognitive performance and mood of men 20. NHS. Six to eight glasses of water ‘still best’ 21. NHS. Sleep and Tiredness