Stress, Sleep & Repeat: Reciprocal Stress-Sleep Associations

Let's explore the crosstalk between stress and sleep, and the dynamic effects between them on biological processes that govern health. Conversations about stress-induced health conditions benefit from the inclusion of sleep, which may be better understood as a factor actively involved in this exchange.

Costs, Implications and Challenges

The intersected costs of stress and dysfunctional sleep are personally problematic, but they are troubling, also, from a population perspective. Both are prevalent in inequitable societies with major global economies that drive productivity maximisation to the detriment of sleep. The COVID-19 pandemic exposed variations in the magnitude of distress among the population (Hamilton et al., 2021). Meanwhile, an estimated 25-30 percent of adults worldwide report persistent sleep issues, with 260 million people projected to be inflicted with sleep dysfunction by 2030 (Stranges et al., 2012).

Prolonged stress exposure is a recognised influencer of disease onset, progression and severity, while expediting mortality (Armon, 2009). Equally, sleep is a key modulator of health, but its dysfunction is long known as an antecedent to disease across a spectrum of severity, with involvement also in all-cause mortality (Brauchi & West, 1959). These aggregate outcomes impose a great burden on society (Jansson & Linton, 2006). Still, despite their ubiquitous nature, both are widely neglected influencers of disease across the lifespan (Prather, 2019). Which start the downward trajectory of effects remains unknown. Sequencing in either direction is theoretically plausible, which develops into an uncertainty about which to treat in medical settings.

The Chicken or the Egg

Stress is as antithetical to sleep as sleep is to stress (Jones & Gatchel, 2018). There is robust evidence that they frequently co-occur and are reciprocally reinforcing (Heffner et al., 2012; Stipp, 2019). And yet we instinctively know this to be true through common experience. High demands, low decision latitude and low resources are salient triggers and maintainers of sleep deprivation (Jansson & Linton, 2006). Yet, those feelings of stress can impede sleep onset and cause multiple wake periods that have us up at night – tossing and turning, fright with a thousand thoughts that overwhelm our natural ability to sleep.

Conceivably all of us have felt how even one night of poor sleep interfered with how well (or not) we functioned throughout the following day. Even the anticipation of excessive demands has been described as the “mechanism of sleep interference” (Stipp, 2019, pg. 104). At the same time, sleep plays a central role in affective processes that promote resilience and recovery from stressful experiences (Germain, 2013). Originating in the prefrontal cortex with connections to the amygdala, deep sleep (~20 percent of total sleep) and rapid eye movement-sleep (REM-sleep; 20-25 percent of total sleep) have been found to consolidate emotions following stress exposure to assist in the recovery of daytime stressors (Stipp, 2019). A lack of sleep, additionally, attenuates the psychological threshold for stress perception (Minkel et al., 2012); heightening our experience of stress, and rendering us less able to cope with everyday burdens.

Mutual Physiological Derangements

Associations between stress and sleep can be understood by the physiological derangements seen in both phenomena. One proposed pathway through which they are connected is in the mechanistic action of sleep supporting neurally integrated immunity that anticipates threat (Irwin, 2019). Disruption to this process would lead to over-sensitised stress experiences. Experimental studies have also offered evidence that sleep deprivation alters the activity of the stress system, along with physiological responses to stress (Meerlo et al., 2008). Another popular proposition is the persistent overproduction of circulating pro-inflammatory factors (i.e., cytokines) and increased immune cell infiltration, that arise in response to the parallel action of stress and dysfunctional sleep. They together give reason for dysregulated inflammatory responses and prolonged states of systemic low-grade inflammation (Irwin, 2008, 2019). Yet, remarkably, there is an indication of a three-way directional association between stress, sleep, and neuroimmunological processes, suggesting a natural confounding that develops into a feedback loop perpetuating a downregulation of processes (Dolsen et al., 2019).

Psycho-Neuro-Immunology

As dual cytokine inducers, it comes as no surprise that stress and sleep have common deleterious health outcomes (Irwin, 2008, 2019). As shared in an earlier post, psychoneuroimmunology (PNI) is the process through which stress disrupts the functionality of various aspects of the integrative network between immunity, endocrinology, and the central nervous system (CNS), in maintaining health. PNI is an equally useful framework to understand how poor sleep activates inflammatory signalling pathways that elevate proinflammatory cytokines (Heffner et al., 2012). PNI research on the reciprocal connections between sleep, immunity and the CNS have demonstrated that sleep enhances immune defences and afferent signals from immune cells that subsequently promote sleep (Besedovsky et al., 2019). Similarly, poor sleep potentiates affective and biochemical stress responses (Germain, 2013; Minkel et al., 2012) that, in turn, contribute to poor sleep (Jones & Gatchel, 2018), while each upregulates inflammatory processes (Irwin, 2008, 2019).

Sleep Soundly, Live Lively

Against this interdisciplinary backdrop, sleep is one component with compelling prescriptive properties; said to have robust efficacy as a targeted behavioural treatment (Jackowska et al., 2013). It has a protective effect and typically increases naturally to promote recovery (Stipp, 2019), plus as a prototypical recovery activity, sleep confers salubrious effects on immunity (Prather, 2019). While the prescription of sleep is an unlikely stress panacea, it has the potential to alleviate many of its symptoms (Germain, 2013; Jackowska et al., 2013). Thus, the ultimate message is to prioritise sleep as an activity worthy of your attention. Sleep soundly to live lively!