Author: Rohan Smith | Functional Medicine Practitioner | Adelaide, SA

Quick Answer: What Is Sleep Hygiene?

Sleep hygiene refers to the daily habits and environmental cues that prepare the nervous system for restorative sleep. Effective sleep hygiene supports the shift from sympathetic (“fight or flight”) activation to parasympathetic (“rest and digest”) dominance, allowing cortisol levels to fall and melatonin secretion to rise in alignment with the circadian rhythm (1,10,15).

Core Concept: Sleep Is an Active Biological Process

Sleep is not passive downtime. During sleep, the brain clears metabolic waste via the glymphatic system, tissues undergo repair, and key hormones involved in immune, metabolic, and cognitive health are regulated. Disrupted sleep hygiene interferes with these processes, increasing the risk of fatigue, mood disturbance, insulin resistance, and impaired stress tolerance (4,11,13).

Solution: Evening Rituals That Signal Safety to the Brain

The Evening Wind-Down Ritual

Deep, consolidated sleep depends on consistent pre-sleep signals that communicate safety and predictability to the nervous system.

1. The 8 PM Kitchen Closure

Late or heavy meals increase metabolic activity, body temperature, and cortisol secretion, all of which can delay sleep onset. When hunger is present, a small carbohydrate-containing snack may support tryptophan transport and melatonin synthesis without overstimulating digestion (1,12).

2. Mastering the Light Environment

Light is the dominant regulator of circadian biology.

• Blue light exposure: Evening exposure to screens suppresses melatonin and delays circadian timing. Blue-light filtering software or amber-tinted glasses may reduce this effect when screen use is unavoidable (2,11).
• Red and low-light environments: Warm or red-spectrum lighting in the final 30–60 minutes before bed has minimal impact on melatonin suppression compared with white or blue light (1,2).

3. Temperature and Sleep Environment

A small reduction in core body temperature is required to initiate sleep. Cooler bedroom temperatures (approximately 18–20°C) and complete darkness support normal sleep architecture and melatonin secretion (8,13).

Nervous System Resets for “Wired but Tired” Sleep

Many individuals with “wired but tired” fatigue patterns experience sleep disruption driven by autonomic nervous system hyperarousal rather than sleep pressure alone.

• Herbal teas: Valerian, lemon balm, and passionflower have been shown to modulate GABAergic activity and may support sleep latency and depth in some individuals (2,14).
• Aromatherapy: Lavender exposure has been associated with increased slow-wave sleep and reduced sympathetic activity (1,15).
• Controlled breathing: Slow breathing at approximately 4.5–5 breaths per minute stimulates vagal tone and reduces heart rate variability associated with stress states (15).
• Guided meditation: Structured mindfulness practices can reduce pre-sleep cognitive arousal and improve sleep quality by downregulating limbic activity (1,15).

The Morning Anchor: Setting the Circadian Clock

Sleep hygiene begins on waking. Morning light exposure suppresses residual melatonin and anchors circadian timing, ensuring appropriate melatonin onset the following evening (11,12). Consistent wake times are particularly important in individuals with altered cortisol rhythms or stress-related sleep disruption.

Sleep Saboteurs to Avoid

• Alcohol: Although alcohol may reduce sleep latency, it reliably disrupts REM sleep and increases night-time awakenings (11).
• Late caffeine: Caffeine blocks adenosine receptors, masking accumulated sleep pressure and delaying sleep onset (12).
• Electronic devices: Evening device use combines light exposure and cognitive stimulation, both of which interfere with circadian and autonomic regulation (2,11).

When to Consider Further Investigation

If sleep hygiene strategies improve sleep onset but not sleep maintenance, underlying contributors such as altered cortisol rhythms, thyroid-related sleep disruption, gut dysfunction, or micronutrient imbalance may be involved.

Next Steps

Persistent insomnia despite optimal sleep hygiene warrants a functional assessment of neuroendocrine and metabolic factors influencing sleep. Identifying these drivers allows targeted interventions rather than symptom suppression alone.

Key Insights

• Consistent sleep and wake times stabilise circadian hormone signalling.
• Darkness, cool temperatures, and reduced light exposure are biological requirements for melatonin release.
• Nervous system regulation is often the missing link in persistent insomnia.
• Sleep disruption may reflect deeper metabolic or endocrine imbalance rather than a primary sleep disorder.

Ready for a Better Night’s Sleep?

If you have implemented evidence-based sleep hygiene strategies and still struggle to stay asleep, there may be an underlying biochemical driver involving stress physiology, gut health, or hormone regulation. A functional assessment can help identify and address the root cause.

Book a discovery call with Rohan Smith at Elemental Health and Nutrition to explore a personalised, evidence-informed approach to sleep restoration.

References

1. Head KA, Kelly GS. Nutrients and botanicals for treatment of stress: adrenal fatigue, neurotransmitter imbalance, anxiety, and restless sleep. Altern Med Rev. 2009 Jun;14(2):114-40. https://pubmed.ncbi.nlm.nih.gov/19594223/
2. Sarris J, Byrne GJ. A systematic review of insomnia and complementary medicine. Sleep Med Rev. 2011 Apr;15(2):99-106. https://doi.org/10.1016/j.smrv.2010.04.001
3. Gooley JJ et al. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. J Clin Endocrinol Metab. 2011 Mar;96(3):E463-72. https://doi.org/10.1210/jc.2010-2098
4. Chang AM et al. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proc Natl Acad Sci U S A. 2015 Jan 27;112(4):1232-7. https://doi.org/10.1073/pnas.1418490112
5. Czeisler CA. Perspective: casting light on sleep deficiency. Nature. 2013 May 23;497(7450):S13. https://doi.org/10.1038/497S13a
6. Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol. 2012 May 31;31(1):14. https://doi.org/10.1186/1880-6805-31-14
7. Ebrahim IO et al. Alcohol and sleep I: effects on normal sleep. Alcohol Clin Exp Res. 2013 Apr;37(4):539-49. https://doi.org/10.1111/acer.12006
8. Reiter RJ et al. Melatonin as an antioxidant: under promises but over delivers. J Pineal Res. 2016 Oct;61(3):253-78. https://doi.org/10.1111/jpi.12360
9. Field T. Cortisol decreases and serotonin and dopamine increase following massage therapy. Int J Neurosci. 2005 Oct;115(10):1397-413. https://doi.org/10.1080/00207450590958574
10. Walker MP et al. Sleep and circadian rhythm disruption and mental health. Sleep Med. 2020 Jan;65:1-9. https://doi.org/10.1016/j.sleep.2019.09.003
11. Wright KP et al. Sleep and circadian misalignment: consequences for metabolic health. Proc Natl Acad Sci U S A. 2013 Apr 2;110 Suppl 1:4250-5. https://doi.org/10.1073/pnas.1217975110
12. Riemann D et al. The hyperarousal model of insomnia: a review of the concept and its evidence. Sleep Med Rev. 2010 Feb;14(1):19-31. https://doi.org/10.1016/j.smrv.2009.04.002
13. Vgontzas AN et al. Chronic insomnia and stress system hyperarousal. Sleep Med Clin. 2009 Sep;4(3):313-320. https://doi.org/10.1016/j.jsmc.2009.05.001
14. Bent S et al. Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006 Dec;119(12):1005-12. https://doi.org/10.1016/j.amjmed.2006.02.026
15. Chien LW et al. The effect of lavender aromatherapy on autonomic nervous system in midlife women with insomnia. Evid Based Complement Alternat Med. 2012;2012:740813. https://doi.org/10.1155/2012/740813