“Many people live in a state of low-grade alertness, mentally tired, but biologically still ‘on.’”
At Heveya, sleep is understood not as passive downtime, but as an active biological process. One that depends on safety, consistency, breathability and physical support. This perspective aligns closely with the work of somatic and breathwork practitioner Constanze Witzel, co-founder of Achievher, who describes rest as a nervous system skill rather than something that automatically happens when the day ends.
In this conversation, Witzel explains why so many people feel exhausted yet unable to truly rest, how long-term stress reshapes the nervous system, and why the sleep environment, from materials to pressure relief, plays a crucial role in recovery.
Quick Overview
- Why rest is a physiological state, not just time off.
- Understanding why we feel exhausted but can’t switch off.
- The difference between sleep quantity and quality.
- Embodied rest and the role of the sleep environment.
Rest Is a Physiological State, Not Time Off
At Heveya, rest is understood as something the body has to recognise as safe before it can truly begin. Stopping work or lying down is not always enough. For many people, rest requires the right physical and environmental cues to allow the nervous system to downshift out of alertness.
As somatic and breathwork practitioner Constanze Witzel explains, “when I say rest is a nervous system skill, I mean that rest isn’t something that automatically happens when we stop working. It’s a physiological state the body must be able to enter.” Many of us, she notes, have trained ourselves to stay productive, focused and always ‘on’, without learning how to transition into safety.
Without those cues of safety, consistency and support, rest often turns into more thinking, scrolling or unconscious bracing. The body may be horizontal, but the nervous system remains active. “To truly rest and recharge,” Witzel says, “the body needs to feel safe enough to relax and restore, which is why the right sleep environment is so important.”
This belief sits at the heart of Heveya’s approach to sleep, creating physical conditions that allow the body to let go, rather than forcing rest through exhaustion.
Why We Feel Exhausted but Can’t Switch Off
One of the most common contradictions people experience is feeling deeply tired, yet unable to relax. According to Witzel, this is because exhaustion and restlessness often coexist. “Many people live in a state of low-grade alertness where they are mentally tired, but biologically still ‘on’,” she explains. The nervous system continues scanning, holding tension and anticipating what comes next.
Over time, this pattern becomes ingrained. Long-term stress trains the nervous system into endurance mode, particularly in high performers who rely on discipline, drive and mental override to get through demanding days. While this may look functional from the outside, internally, the system loses flexibility. Shallow sleep, waking unrested, body aches, emotional reactivity and an inability to fully switch off can all emerge, even when nothing appears to be ‘wrong’.
This is where physical comfort becomes more than a luxury. A sleep surface that supports the body properly, regulates temperature and reduces micro-tension can help interrupt this constant low-level vigilance, giving the nervous system permission to soften.
Regulation, Breath and the Difference Between Sleep Quantity and Quality
Sleep duration alone does not guarantee restoration. As Witzel points out, “a dysregulated nervous system can sleep for eight hours and still wake up exhausted.” What matters is whether the body feels safe enough to access deeper stages of rest.
Breath plays a central role here. “Breath is one of the most direct ways to communicate with the nervous system,” she says. Slow, unforced breathing sends a biological signal of safety, telling the body there is no immediate threat. Unlike mindset tools, breath works beneath conscious thought, helping the nervous system move more fluidly between activation and rest.
The same principle applies to sleep itself. Environments that feel calm, breathable and predictable reduce nighttime micro-awakenings and unconscious tension. Regulation supports sleep that feels genuinely restorative rather than simply unconscious.
Embodied Rest and the Role of the Sleep Environment
True rest is not just mental. It is felt physically. Witzel describes embodied rest as relaxation that shows up in the body through slower movements, deeper exhalations, softer jaw and shoulders, and the ability to be still without reaching for stimulation.
The nervous system, she notes, is constantly reading its surroundings. Harsh lighting, synthetic fabrics, heat retention or physical discomfort can all be interpreted as signals to stay alert. In contrast, “a sleep environment that feels quiet, breathable, supportive and consistent helps the body feel safe enough to soften.”
This is where materials matter. Natural, breathable fibres help regulate temperature and reduce sensory irritation, while proper pressure relief minimises unconscious muscle guarding throughout the night. When the body no longer has to hold itself, the nervous system can finally release its subtle grip.
Creating the Conditions for Deeper Rest
Consistency is key. “When the body knows what to expect, it stops bracing,” Witzel explains. “That consistency is what allows rest to deepen and become truly restorative.”
At Heveya, this idea of consistency runs through every layer of sleep, from the buoyant support of natural latex mattresses to breathable bamboo bedding designed to work with the body rather than against it. Together, these elements create an environment that the nervous system can trust night after night, allowing rest to move beyond collapse and into genuine recovery.
Key Takeaways
- Rest is a physiological state, not simply time off. The body must feel safe before it can truly recover.
- Chronic stress trains the nervous system to stay in low-grade alertness, even during sleep.
- Sleep quality depends on regulation, not just duration. Eight hours is meaningless if the nervous system remains activated.
- Breath is one of the most direct ways to signal safety to the nervous system, supporting deeper rest.
- The sleep environment matters. Breathability, pressure relief and consistency help reduce unconscious tension and allow the body to let go.
