Managing Personal Energy: Sleep and how to do it better

Nov 28, 2023

Managing Personal Energy: Sleep and how to do it better

In this blog, Deborah Hulme explores an important contributor to personal energy; sleep. Particularly, the importance of sleep and how to encourage more regular sleeping patterns.

Many of us suffer from interrupted or fitful sleep at certain moments in life and sometimes, as we age, restful, non-interrupted, sleep has a tendency to become more difficult. If we want to maintain or increase personal energy, then it is important to better understand the role of sleep as well as how to encourage sleep.

Typically, adults need between seven to eight hours of sleep per night

The amount of sleep required differs person to person and the best way to find out is via trial and error, noticing what does and does not work. The common rule of thumb for adults though is between seven to eight hours sleep per night. Individuals who can thrive on less than six hours a night account for about 5% of the population and have a rare genetic mutation that facilitates short sleeping with no apparent ill effects (Klein, 2019). Whilst for the rest of us, if we reduce to six hours or less, we start to see the negative impact within a few days as our performance drops to that of a person who has not slept for 48 hours (Van Dongen, Maislin, Mullington and Dinges, 2003).

As we sleep certain areas of the brain are more active than when we are awake. Sleep enables our brain to restore itself, consolidate memories and complete a toxin wash, flushing out natural toxins to bring brain toxicity back to healthy levels (Xie et al., 2013). It also works to make sense of what we do, consolidating our learning so that on waking we have access to insights and answers that were not there before. Also known as those Aha or Eureka moments.

Lack of sleep impairs our logical reasoning, decision making and creativity

In contrast, for example, lack of sleep impairs our logical reasoning, decision making, memory and creativity whilst increasing impulsiveness and poor judgement. In addition, those of us who engage in 5-hrs or less of sleep per night have a 50% chance of being obese. This being due to a connection between sleep loss and the release of the hunger hormone ghrelin, which directs us to take in more sugar and carbohydrate when tired (Taheri et al., 2004). There are many good reasons to cultivate healthy sleeping habits.

So, what can we do, to improve how we sleep?

We can start by aligning with our natural rhythms, particularly the Circadian and Ultradian rhythms. Focusing on our Circadian rhythm, which is the biological system that, among other things, controls our sleep/wake pattern over a 24-hour period. The Ultradian rhythm we experience throughout the day as high and low frequency periods of brain activity.

Different systems of the body follow the Circadian rhythm, all synchronized with a master clock in the brain, not an actual clock but a group of neurons located above the roof of the mouth. These neurons are heavily influenced by, and sensitive to, light, particularly sunlight, which operates our internal cellular timer and is the reason why the Circadian rhythm is tied to the 24-hour cycle of day and night (Blume, Garbazza and Spitschan, 2019).

Morning light triggers melatonin which informs our internal clock to wind down at night

Bright morning light stimulates our system to produce cortisol, a hormone that regulates different processes throughout the body, including metabolism and the immune response as well as playing an important role in helping the body respond to stress. Cortisol release makes us more alert with enough energy to get up and face the day. However, morning light also signals to our internal clock to set a timer for our body to release a different hormone, melatonin, about 12-14 hours later. Natural melatonin, released from the pineal gland in the middle of the brain, is essential for sleep and establishing stable sleep/wake patterns. This rhythm of cortisol and melatonin release happens within all of us continuously and automatically. It is when the rhythm is out of sync that it impacts our ability to sleep (Segal et al., 2011)

Our internal Circadian clock responds best to sunlight. The more we can view sunlight, even sun behind cloud, early in the day, the more we activate the cortisol pulse for increased alertness and activity whilst at the same time setting the timer for later melatonin release to aid sleep. It’s considered by researchers to be 50 times less effective to view sunlight through a window. And even internal house or office lights do not have the same impact, although bright LED lights are said to be the closest to natural sunlight (Jamrozik et al., 2019)

It does not take long for cortisol to pulse and the timer to set. An estimated two to three minutes when in bright sunshine and up to 15 minutes if there is heavy cloud. The key is to obtain appropriate light exposure before the Circadian dead zone, which is said to be around the middle of the day, between 10am and 4pm, when light has no impact on our internal clock (Zhu and Zee, 2012). As the day draws to a close and the sun starts to set from around 4pm our clock starts to adjust for the onset of rest and sleep. Dependent on the time we take in our morning light we can adjust our timer for natural melatonin release backwards or forwards, so impacting our sleep pattern.

Keep the lights low and reduce exposure to blue light post-8pm

However, as late evening approaches, from around 8pm, the more we expose ourselves to bright light, particularly blue light, the more we stimulate ourselves into wakefulness, thus hampering our ability to sleep. It’s far better to keep the lights low and wear blue blockers, if needed, post 8pm.

As we all have different light exposure needs, we may need to experiment to find our optimal light timings, however, the foundation of good sleep is a healthy and stable Circadian rhythm. For those on shift work, it’s important to get as much of the evening light as possible, before shift start, whilst reducing morning light to a minimum, which can be helped by wearing a pair of sunglasses if outside at the end of shift.

In addition to light management, there are other things we can consider to enhance sleep and increase personal energy. For example, we can consider:

  • Reducing caffeine intake, particularly in the afternoon
  • Avoiding exposure to blue light during the evenings, particularly post 8pm
  • Increasing our exercise regime whilst at the same time ensuring we regulate our sleeping, eating and exercise cycles and stick with the timings

Taking a hot shower or bath an hour or two before bed also directs our body towards rest. The water heats our body until we get out of the shower, at which point water evaporation cools the body temperature. Body temperature has a direct influence on our internal clock and as our body cools a signal is sent to the brain indicating time to sleep, hence feeling sleepy following a hot shower or bath.

Light management, however, is perhaps the most powerful. It works the same way for all regardless of whether we have full sight or not, only becoming ineffective if the eyes have been physically removed (Lickey et al., 1977).

We can all assess whether we need more sleep through observation and listening to our body; for example, are we irritable and/or grumpy for no reason, do we feel excessively tired during the day or find it hard to either go to sleep or stay asleep during designated sleep hours

Lack of sleep has a direct impact on personal energy, performance and wellbeing. It is not a given that we all sleep well, and good sleep often requires direct proactive action if we are to maintain healthy sleep habits. There are a few of us who function well as night owls, however, this may be down to genetic difference or it could be because we are simply not getting enough sunlight or bright LED light, on waking to set our internal clock for appropriate melatonin release before heading to bed.

For more information on the ways in which we can better manage our own resources for greater wellbeing, resilience and performance, get in touch with us at or click here for more information on our programmes and courses.

Further reading

  • Walker, M. and van der Helm, E., 2009. Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin, 135(5), pp.731-748.
  • Corsi-Cabrera, M. and Poe, G., 2014. The role of sleep in processing emotional and contextual information: from mechanism to impact on everyday life and emotional health. Experimental Brain Research, 232(5), pp.1399-1401.
  • Anderson, K. and Bradley, 2013. Sleep disturbance in mental health problems and neurodegenerative disease. Nature and Science of Sleep, p.61.
  • Zisapel, N., 2018. New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. British Journal of Pharmacology, 175(16), pp.3190-3199.