SLEEP TEMPERATURE

A core tenet of human physiology is the maintenance of our body temperature, generally accepted as 37°.2 C. For perspective, consider that the maximum setting on a hot tub or sauna is 40o C. Our bodies function optimally at the correct temperature, with processes like our immune response, digestion, cognitive function, and general operation dependent on it.

This balance is delicate. A variation of just 2oC can result in hyperthermia (overheating) or hypothermia (extreme cold). A 3oC increase could potentially cause heatstroke and death, while a 3oC decrease could lead to equally devastating effects. Symptoms such as intense shivering or profuse sweating, often dismissed as minor inconveniences, are serious signals that the body is fighting to maintain its proper temperature.

Our bodies are however highly adaptable. As daylight fades, our productivity lessens, and our bodies encourage rest and sleep. This synchronizes with the sun setting and environmental temperatures dropping. Correspondingly, our core body temperature slightly decreases from around 37.2°C to 36.1°C, creating a mild hibernation effect. This dip plays a significant role in our circadian rhythm, inducing sleepiness and signalling it's time to rest, heal and rejuvenate.

Towards the end of our sleep, sunrise and the warming effect of its rays, stimulate us to awaken and start a new day.

Understanding this principle allows us to optimize our sleep. For instance, wearing clothes or heavy bedding in bed could prevent sufficient body cooling, contributing to insomnia. Similarly, late bedtimes followed by early morning sunrises could disrupt sleep due to the warming effect of sunlight.

Extreme conditions are hazardous: sleeping without bedding in a cold environment risks hypothermia, while excessive bedding or warm environments increase the risk of hyperthermia and heatstroke.

Maintaining the correct core temperature, or thermoregulation, is a complex, multifactorial process. Our cardiovascular system plays a major role, transferring warmth from the core to our capillary beds, which then dissipates the heat through convection or conduction.

When sleeping, maintaining a comfortable microclimate is essential. This microclimate, assuming a naked body, ideally should be around 29-32°C, conducive to a restful sleep. If the room temperature is 0°C, we would need plenty of bedding and clothing to create this localized microclimate.

Humidity also plays a crucial role. Ideally, the relative humidity should be around 40-60%. Higher humidity can make the environment feel warmer and disrupt sleep, while low humidity can lead to dry skin and respiratory issues.

Our skin, our body's largest organ, needs to breathe and perform its functions during sleep. These include active perspiration, releasing moisture, not only to cool the body but also to eliminate waste toxins.

This is why choosing the right bedding and clothing is so crucial. Many people unknowingly sleep in synthetic clothing or use petroleum-based bedding like nylon duvets, both of which inhibit the body's ability to breathe and regulate temperature.

Consider for one moment, sleeping in an environment reminiscent of our ancestors: on fresh straw, with a thin organic cotton sheet in an ambient temperature of around 29°C. This allows perfect thermoregulation and optimal skin functions, like moisture removal.

Of course, you probably won't want to sleep on straw, but use this as a starting point. Pocket spring mattresses such as those produced by #ViSpring, use a combination of steel pocket springs, a natural fibres such as wall and cotton to perfectly facilitate thermo regulation during bed rest. It's also worth noting that Vi Spring have the Royal Warrant, suggesting that Kings and Queens, have slept on them, and I guess that there clinicians are equally keen to optimise sleep.

There are also modern advancements like Diamond Vestims mattresses, that can further improve skin function during sleep. These mattresses use a series of air chambers that inflate and deflate against the skin, providing a mild form of massage throughout the night. This can greatly improve cardiovascular health, increase resting blood flow, enhance endothelial function (the body's ability to distribute blood effectively), and improve thermoregulation.

Diamond #Vestims mattresses, invented by #SquirrelMedical, help cool the body by facilitating conductive heat loss. They are particularly beneficial during periods of high temperature, where there's an increased risk of heatstroke. By understanding and harnessing these principles, we can make sleep not just a necessary routine, but a pathway to better health and wellbeing.

There are other tips that can greatly improve your ability to thermoregulate better and hence improve your sleep. Thermoregulation requires sufficient hydration and minerals / nutrients within your diet. Persons that are dehydrated, are at greater risk of heat stroke than those fully hydrated. It is therefore worth considering your dietary intake if you want to improve your sleep. Of equal importance is obtaining sufficient exercise. Exercise has been shown to improve about his ability to distribute blood flow (heat) effectively.

By understanding and harnessing these principles, we can make sleep not just a necessary routine, but a pathway to better health and wellbeing.

PUB MED REFERENCES

Yousef H, Ramezanpour Ahangar E, Varacallo M. Physiology, Thermal Regulation. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499843/

Kr?uchi K, Cajochen C, Werth E, Wirz-Justice A. Functional link between distal vasodilation and sleep-onset latency? Am J Physiol Regul Integr Comp Physiol. 2000 Mar;278(3):R741-8. doi: 10.1152/ajpregu.2000.278.3.R741. PMID: 10712296.

Sawka MN, Montain SJ, Latzka WA. Hydration effects on thermoregulation and performance in the heat. Comp Biochem Physiol A Mol Integr Physiol. 2001 Apr;128(4):679-90. doi: 10.1016/s1095-6433(01)00274-4. PMID: 11282312.

Baker G, Bloxham S, Laden J, Gush R. Vascular endothelial function is improved after active mattress use. J Wound Care. 2019 Oct 2;28(10):676-682. doi: 10.12968/jowc.2019.28.10.676. PMID: 31600104.