Is there anything worse than facing up to a mountain of work and a tight deadline when you’re already feeling tired? Not just physically tired, but that eyeball crushing, 10-ton-weight-on-your-shoulders mental fatigue.

It doesn’t have to be this way. Even during peak busy times, you can help combat mental fatigue by using these 5 tips.

1. Fuel up right.

While that extra cup of coffee keeps you alert in the short term, additional caffeine paradoxically adds to fatigue levels over time. That’s because it competes directly with adenosine; the brain chemical that helps us to stay awake during the day and wind down at night. Caffeine speeds up neuronal firing, which over time depletes mental energy. If caffeine blocks too many of the adenosine receptors, the brain responds by creating more, meaning it now takes more caffeine to give us that same alertness boost – trapping us into the cycle of drinking yet more coffee.

Refueling right is about drinking enough water to stay hydrated and eating small regular meals that include cognitive boosters such as leafy greens, lean protein, seeds and nuts, legumes, whole grains and deeply pigmented berries.

2. Stand Up for Your Brain

Exercise prior to mental work primes the brain to perform at its highest capacity. We think more clearly, are more focused and productivity increases. Standing also boosts attention by over 40%.  Studies show that rats’ brain function and problem-solving abilities are improved when they have access to a running wheel.

While a desk-cum-treadmill has yet to hit the market, there are ways to encourage increased activity at work such as by using variable height desks, opting for standing or walking meetings, or choosing to use the stairs. It all counts towards improved mood, mental performance and more energy.

3. Nap on the job

Being tired is exhausting! That’s why savvy workplaces recognise the benefit of providing a nap room. A place where you can shut the door, turn off the light and take a short 20 minute snooze can restore mental energy, memory and boost productivity.

4. Give your brain a break

Blocking your day into chunks of 60-90 minutes interspersed with a well earned brain break of 20 minutes gives the brain the time it needs to reboot, restore and refresh, ready for that next chunk of focused work.

5. Go home!

All that extra time spent staying late, taking work home or toiling over the weekend is not only tiring, it’s counterproductive. Stanford researcher John Pencavel revealed how working beyond 48 hours a week leads to a significant nosedive in productivity due to slower speed of mental processing, higher rates of error, increased stress levels and poorer sleep patterns.

Managing mental fatigue begins by putting in place the right boundaries to ensure you can always work to your best.

Dr. Jenny Brockis is the Brain Fitness Doctor specialising in the science of high performance thinking and author of Future Brain: The 12 Keys To Create Your High-Performance Brain.