Do you ever have those days when even though you had a long, peaceful sleep, you wake up feeling exhausted?
Well it turns out that there are a lot of other factors that could be affecting your energy.
From poor food choices to even your choice in candles, it turns out a lot of factors can affect your energy levels so if you're fed up of feeling sluggish, why not consider these options?
This trace element is important for a healthy thyroid and immune system, and aids cognitive function, among other benefits.
Common symptoms of a selenium deficiency are tiredness, mental fog and hair loss.
Selenium-rich foods include seafood, eggs and Brazil nuts. Nutrition Australia says just two Brazil nuts a day provides 100 percent of an adult's RDI for selenium. And don't overdo it: too much selenium can be harmful, so you should consider selenium supplements only if your doctor recommends it.
The theory goes that when you eat salt, you drink more, thus getting rid of the excess mineral.
Unfortunately, our bodies have grown used to an increased amount of salt, so we no longer feel as thirsty as we should.
The acid/base balance gets out of sync, making us lethargic. So limit your salt intake to ⅓ tsp-½ tsp a day.
According to an article in the journal Scientific Reports, around 1.1 billion people are thought to be deficient in zinc worldwide.
Zinc is involved in many metabolic processes, and a lack of it leaves us feeling exhausted. To meet your daily intake – 14mg for men and 8mg for women – seek out foods high in zinc, such as meat, wheat germ, dairy (milk and cheese), and legumes.
A weight gain of just 2kg can make us tired, says American physician Erika Schwartz, who has researched the causes of exhaustion.
"The heart comes under greater strain and that tires us," says Dr Schwartz.
If you're watching what you eat, make sure you're still getting your daily quota of vitamins and minerals.
READ MORE: How to lose 5 kilos in 2 weeks.
Who doesn't love a sweet treat – especially when we're feeling low on energy.
But the conversion of sugar into energy creates acids in our cells that need to be neutralised by an enzyme containing vitamin B1.
If you eat too much sugar, you'll eventually end up deficient in vitamin B, reducing the ability to function. Research from the American Academy of Sleep Medicine also found a greater sugar intake was associated with more shifts between deeper and lighter sleep stages.
A tidy space makes us feel good… and now science can explain why.
Neuroscientists at Princeton University have discovered that, to manage the daily flow of information, our brain needs to constantly sort information into subconscious mental categories, which is tiring. For our brain to restore itself, it helps if our surroundings are uncluttered.
Fresh air contains just 0.04 percent carbon dioxide (CO₂). If, however, we're sitting with 10 other people in a 30m2 room, the ratio changes to around 0.3 percent CO₂ after an hour.
Why does this matter? Because, say German researchers, "from readings of about one percent onwards, CO₂ has a narcotic-like effect on the central nervous system." We don't yet understand the mechanism for this, but we know that a rise in CO₂ reduces blood pressure, resulting in our haemoglobin binding less oxygen, which makes us tired.
So open a window and let air into your rooms in five-minute blasts!
Do you tend to slouch when you walk? It may be time to pull those shoulders back.
Researchers from San Francisco State University found that people who constantly walk around with sagging shoulders end up getting tired.
"An upright posture increases energy," says study director Professor Erik Peper.
Fast food – food high in salt, saturated fatty acids and sugar – may give us a burst of energy intially, but eating unhealthily can affect your energy levels in as little as one week.
A study from the University of Cambridge in the UK found that within nine days of adopting a high-fat diet, rats were only able to run half as fast on a treadmill as rats fed a more balanced diet.
Our immune system needs protein. If its stores are empty, it starts tapping into the muscles.
In doing so, the body also uses up the amino acids we need for metabolism, making us lethargic.
The Australian National Health and Medical Research Council recommends a daily intake of 0.75g protein per kilo of body weight for women and 0.84g/kg for men.
Regular exercise helps combat tiredness, says a study by the University of Georgia, which looked at adults with sedentary jobs who started doing light exercise – like bike riding or brisk walking – for 20 minutes three times a week. After six weeks, the participants felt less tired.
However, avoid exercise just before you go to sleep as it stimulates circulation and wakes you up.
Excessive exercise not only makes you tired; it can even cause burn-out and lead to injuries.
So even if you have your sights set on a goal – whether it be a competition or weight loss – never train to your maximum limits. The body also needs recovery phases after every exertion.
Music is great for the soul… but it can also be a stressor.
Researchers from Lehman College at the City University of New York have found that our cardiovascular system has a clear and extreme reaction to noise. The pulse quickens, blood pressure rises, and adrenaline is released. These are all the same reactions that occur with stress – and stress drains and tires us.
So Spotify away, by all means, but enjoy some silence in between.
Bananas are good for us, but more than two acts almost like a sleeping tablet.
This is because the fruit contains the amino acid tryptophan, which our brain uses to produce the happy hormone, serotonin. But in high doses this can also make us sleepy – incidentally, the same also applies with hot chocolate.
A fluid deficiency of just two percent of our body weight is enough to make us lethargic, so it's important to ensure you drink enough.
Across the day you should aim to drink a total of 2.8 litres from both food and fluids, with 2.1 litres (about eight cups) coming from water or other drinks. But as the gut absorbs between 800ml and 1L an hour, it's better to have one large glass of water an hour to help keep you awake.
WATCH: 6 tips for drinking more water. Post continues after video...
We tend to associate candles with relaxation, but many are made from paraffin, and as they burn, they release substances such as benzene and toluene into the environment.
Not only do these worsen air quality, they also make us tired. If you want to inject a little ambience in your living space, opt for beeswax candles instead.
It's vital when it comes to warding off fatigue, with studies showing a deficiency can lead to daytime tiredness.
Our body is able to produce its own vitamin D, and the main way is through being out in the sun – although foods like oily fish, eggs and dairy also contain the vitamin, and some foods are fortified with vitamin D too.
During summer, being outside for around 10 minutes mid-morning or mid-afternoon should be enough to meet your vitamin D needs – though it's still wise to practise good sun protection.