Five daytime hacks to fight fatigue and improve your sleep (while you're awake)

The secret to feeling good after a night's sleep may start during the day. Here are some tips on how to improve your sleep and feel less tired.

Feeling tired? You're not alone – and you may be thinking about how to tweak your sleep habits as a result.

Often, the strategies we're told will help us feel more rested focus on night-time strategies, like having a regular bedtime and not scrolling on your phone in bed. (Read more about some science-backed ways to improve your sleep).

But getting a good night's sleep isn't just about your nighttime routine. And feeling refreshed isn't always about getting a good night's sleep. There are other things you can do earlier in the day, while wide-awake, that can have an effect.

Here are five ways to feel more rested, increase your energy levels and, yes, even improve your sleep that don't have to do with changing your sleep habits themselves.

Around one out of every three people worldwide lack sufficient iron levels. Particularly susceptible groups include infants and toddlers, girls and women of reproductive age (thanks to blood loss during menstruation), pregnant people, endurance athletes, vegetarians (especially vegans) and frequent blood donors. But anyone can wind up with an iron deficiency or its potential consequence, iron-deficiency anaemia – and symptoms can include tiredness and fatigue, but also restlessness and waking at night.  

If you frequently feel tired, despite making tweaks to your sleep habits, it may be worth consulting your physician about testing your levels of ferritin (a protein that helps store iron), or haemoglobin, which transports oxygen throughout the body.

Even if you don't have an iron deficiency, being mindful of nutrition can help avoid one. Sources of the most readily absorbed iron, called heme iron, include meat, fish and eggs, while non-heme sources (like beans and green vegetables) can have their bioavailability boosted by consuming a vitamin C-rich food at the same time.

Several large-scale studies have found that adults who consume more fruits and vegetables report better sleep, while those who consumed more fast food and soft drinks report worse. In particular, research has found that individuals who eat the so-called Mediterranean diet – characterised by high levels of vegetables, fruits, nuts, legumes, whole grains and low-fat dairy – sleep more consistently, and better, than those who do not. Meanwhile, people who slept less than five hours per night have been found to consume lower amounts of iron, zinc, selenium, phosphorus, and magnesium, as well as vitamin C, lutein and selenium, than those who slept more.

It's always hard to untangle the relationship between cause and effect, particularly with topics as tricky to study as nutrition and sleep. For this reason, it's not clear from most studies whether people eat better when they sleep more, sleep better because they're eating better, or both.

Still, it's not just that we're likelier to reach for junk food when we're tired – it can also alter the kind of sleep we get. One study of 15 young men in Sweden found that when they consumed high fat, high sugar diets their brain waves changed as they slept and the quality of deep sleep they had deteriorated. When they switched to a healthier low fat, low sugar diet, their deep sleep improved.

While such studies are small due to the difficulties in collecting brain activity data as someone sleeps – they need to attend a sleep lab and be monitored through the night – there is plenty of other evidence pointing to the benefits of a healthier diet on sleep.

Some randomised controlled trials indicate that getting our five (or ten) vegetables a day can boost our sleep. One study of more than 1,000 young adults who ate less than three servings of fruits and vegetables per day, for example, looked at their sleep after they increased their intake. Three months later, women (but, interestingly, not men) were twice as likely to improve their insomnia symptoms, had slightly better sleep quality, and took less time to fall asleep if they increased their servings to at least six per day, compared to those who had not.

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Meanwhile, a randomised controlled trial found that when children were put on a diet that included eating green vegetables five times per week, they said they felt more rested and had better sleep. The researchers wrote that this is likely down to the high levels of vitamins in green vegetables, particularly A and C, which also help with the absorption of other minerals that can help with sleep, like iron.

While the precise relationship between physical exercise and sleep is still being researched, physical activity, in general, seems to help us sleep longer and better – and you don't have to do as much as you might think. 

One authoritative 2015 meta-analysis of 66 studies, for example, found that even just a few of days exercise helped people to fall asleep faster and sleep more, while exercising more regularly also improved sleep quality. Most of the effects were small, but they were larger for people who had sleep complaints. In other words, adults who struggle with their sleep might especially benefit from working up a sweat.

Other studies indicate that workouts don't have to be intense, or even every day, to make a difference. One review found that working out three times a week had better outcomes for sleep than working out every day (or just once a week). Moderate intensity exercise may promote sleep more than a high intensity, and that even just 10 minutes a day of exercise may make a difference. And another review of the research indicates that exercising in the evening, up to two hours before going to bed, doesn't disrupt sleep – good news for those of us who don't have any other time to lace up our trainers.

Improving sleep isn't the only way that exercise may help us feel more rested, however. Research has found that doing physical activity makes us more likely to feel refreshed and even to say we slept better the night before – no matter how well we actually slept.

It appears on many people's New Year resolutions list, but for those of us who regularly drink or smoke, suddenly cutting it out can be hard to stick to. That is perhaps because approach-orientated goals – those that are attainable and where success can be easily measured, such as adopting a new habit or introducing a positive change – are more successful than those that focus on abstinence. This year, though, you may want to try kicking a drinking or smoking habit as a way to feel more rested.

Smoking has been linked to having a harder time falling asleep and to less restorative, slow-wave sleep.

Drinking also seems to result in worse sleep, although there's a caveat. Having up to two or three drinks before bedtime may make us feel sleepier, but only at first: if we continue to tipple like this for three days (or more), the effect backfires, with regular drinking linked to greater risk of insomnia. Other research has found that even as little as a single drink before bed changes our sleep physiology, with drinkers falling asleep faster and sleeping more soundly in the first half of the night, but waking up more in the second half of the night and getting less REM sleep. Drinking may also mess with our circadian rhythm, reduce the amount of total sleep we're able to get and make any sleep disorders related to breathing, like sleep apnea, worse.

As the BBC has covered before, when it comes to the question of whether eating breakfast helps with weight loss (or maintaining a healthy weight), the evidence is mixed. One series of randomised controlled trials, for example, found that there's no clear impact of eating (or skipping) breakfast on outcomes like body mass.

The benefits of breakfast are a little clearer, though, when it comes to the meal's potential effect on feeling mentally alert and sharp. One review of 43 studies found that eating breakfast may improve our memory and concentration – and while these effects were generally small, they were also consistent. The same has been found to be true for children, with randomised controlled trials finding that children who eat a meal after they wake up experience a boost to their attention, memory and executive function.

Other research has found that eating breakfast might help with feeling less tired. One study of 127 medical school students, for example, found that those who ate breakfast reported feeling less fatigue than those who skipped it.

Eating at consistent times might also be beneficial. Both the study of medical school students as well as other research, including a study of more than 1,800 graduate students in Taiwan, found that participants who ate at irregular times experienced more fatigue than those who did not.

These two studies were observational, so it's possible that the more fatigued participants were simply less likely to make the time for breakfast or to eat at regular times. Still, a growing body of research has found that our circadian rhythms affect when we eat, and that when we eat affects our circadian rhythms – so it seems likely that the relationship goes both ways.

If nothing else, if you struggle with tiredness, squeezing in time for a couple of eggs or a bowl of porridge before you head out the door might be one more relatively easy fix to try.

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