According to the US Department of Health and Human Services poor sleep leading to cognitive fatigue results in US$50 billion in lost productivity each year. While Safe Work Australia reports how mental stress costs the economy AU$10 billion per annum — an alarming increase from the AU$730 million reported in 2010.

Fatigue is more than just feeling tired all the time, it is a mental state that depletes motivation, increases emotional vulnerability and causes difficulty in processing information. In addition to being detrimental to physical health, mental fatigue reduces memory, problem solving and the ability to demonstrate sound judgment when making decisions.

Contributing factors include high stress levels, insufficient down time and insufficient sleep.  Addressing these is essential to restoring the cognitive stamina required to stay at the top of your game.

Place a High Value on Sleep

Choosing to invest in good quality sleep increases mental agility and maintains better cognitive functioning in later life.

Individual requirements vary but most of us need 7–8 hours to function at our best. Each night we complete 4–6 sleep cycles that include time spent in deep sleep when we consolidate long-term memory and REM sleep when we dream to get creative. We need both to function at our best. Too little sleep leads to an overactive limbic system that diminishes mood, increases a negative perspective and adversely affects decision-making.

Get an extra 20 minutes of sleep

Going to bed 20 minutes earlier each night helps to pay off some of our long-standing sleep debt, helping improve performance and memory.

The alternative is a 10–20 minute power nap. The brevity of the nap is to maintain light sleep and avoid sleep inertia that horrible groggy feeling experienced when waking from deeper sleep. Taking a nap or trying bright light exposure after lunch improves postprandial cognitive flexibility, boosts learning capacity and enhances memory. Finding a quiet room where you won't be disturbed is all that is required. Turn off the light, set the timer and enjoy that snooze.

Moderate your Stress

Stress is normal and contributes to performance, except when chronic and running too high. Elevated stress hormones interfere with sleep and increase the risk of mental illness. Reducing stress can be achieved by taking sufficient brain breaks during the day. This could be a 15-minute break between meetings, getting outside for a quick walk or a jog at lunchtime, pressing the pause button for a period of quiet, reflective thought or undertaking a brief meditation practice.

Remember to switch off

Working hard can be enormously rewarding, but working too much leads to a decline in performance and an inability to disconnect from work.

Like any energy source, mental energy requires renewal. Moderating how long you spend at work contributes to higher productivity, as revealed by John Pencavel from Stanford University.

Switching off can be about doing something else that gives you pleasure such as exercise, participating in a community project or singing in a choir.