How to regulate your nervous system and stress with Dr. Jay Wiles

Originally published on December 5, 2023

Nervous system regulation starts with understanding how stress shows up in your body, and what you can do to change it. In Episode 250 of the WHOOP Podcast, Dr. Jay Wiles, a clinical health psychologist and Health Behavior Coordinator at WJB Dorn VA Medical Center and the Greenville Outpatient VA Clinic, joined Kristen Holmes, Global Head of Human Performance, Principal Scientist at WHOOP, for a practical discussion on HRV, mental health, sleep, relationships, breathing, and stress resilience.

Wiles explains why heart rate variability can reflect more than training load, how daily habits shape autonomic balance, and why biofeedback gives people a trainable path back to control. If you want a clearer way to connect stress, physiology, and action, this conversation is worth your time.

To listen to Episode 250 of the WHOOP Podcast in full, head to the WHOOP Podcast on YouTube.

How does mental health affect your autonomic nervous system?

Mental health affects your autonomic nervous system by changing how your body allocates energy, detects threat, and recovers from strain. Wiles' central point is that HRV is not only a performance metric, it is also an accessible signal of how the human stress response is functioning.

He argues that people often separate mental health from physical health because physical health feels easier to quantify. HRV challenges that split. When stress, anxiety, or emotional overload rise, the autonomic nervous system shifts resources toward protection. That shift can show up in the same data stream that also reflects recovery, readiness, and adaptation to training. The body does not keep a separate ledger for mental and physical strain, which is one reason this discussion pairs well with WHOOP's earlier look at mental and physical strain.

Wiles also makes a second point that matters for day to day use. HRV is useful as a morning or overnight metric, but it can also be part of active training. In clinical work, he has used HRV for close to 15 years to help people see what the nervous system is doing in real time and then practice changing it. That means the metric can function as both a dashboard and a training tool.

Wiles puts the clinical value of HRV plainly.

"Heart rate variability just happens to be the single greatest non-invasive proxy that we have for stress response and mental health functioning."

What you should take away

• HRV can reflect mental load as well as physical load.
• The autonomic nervous system responds to psychological stress with measurable changes in physiology.
• HRV is useful both as a passive metric and as an active training signal.
• Mental health and physical health share the same stress-response machinery.

If you want to hear Wiles unpack how HRV reflects mental strain, listen to the full episode on Spotify

What can a lower HRV tell you about stress?

A lower HRV tells you the stress response is active and flexibility is reduced. In practice, Wiles sees this when people insist they feel fine, while their physiology shows a system carrying more load than they realize.

Holmes added a useful population-level data point from WHOOP members. Reported stress was associated with an unfavorable HRV change 63% of the time, with women at 64% and men at 62%. The average shift was a decrease of 4 milliseconds. Wiles treats that kind of movement as evidence that stress has moved from a vague feeling into something the body is actively managing.

His clinical examples make the point more concrete. High-level executives and athletes often arrive convinced that stress is under control. Then their data show suppressed HRV, disrupted sleep, or a nervous system that stays activated longer than it should. Wiles' explanation is that the body responds to perceived threat, not only literal danger. Laundry piling up, conflict at work, time pressure, and uncertainty can all be interpreted as signals that resources need to be recruited for protection.

The larger concern is not a short stress response. The larger concern is a system that stays elevated after the event has passed. Once sympathetic activation remains high, people often see worse sleep, a narrower cognitive range, and a tougher time recovering. That pattern lines up with earlier WHOOP reporting on stress, sleep, and cognitive function.

Wiles reduces the clinical challenge to one sharp line.

"You can try to lie to your physiology, but it doesn't lie back to you."

What you should take away

• A lower HRV often signals an active stress response and less autonomic flexibility.
• WHOOP data discussed in the episode showed reported stress aligned with an unfavorable HRV shift 63% of the time.
• Perceived threat can suppress HRV even when the stressor is not physically dangerous.
• Recovery gets harder when the nervous system stays activated after the stressor ends.

If you want to hear Wiles go deeper on perceived threat and HRV, watch the full episode on YouTube

Which daily habits most strongly shape nervous system balance?

The habits that most strongly shape nervous system balance are exercise, sleep, nutrition, alcohol, caffeine, relationships, and mindset. Wiles looks at those inputs together because HRV is shaped by the total load on the system, not by one habit in isolation.

He starts with movement. Cardiorespiratory fitness is closely tied to baseline HRV, so long stretches of sedentary time and lower VO2 max tend to move the nervous system in the wrong direction. From there, Wiles looks hard at sleep quality and sleep quantity. Frequent awakenings, long sleep latency, and short nights all show up as signs that the system has less room to adapt.

Nutrition is another major bucket. Wiles watches energy intake, food quality, and meal timing, especially late eating close to bedtime. He is especially direct on alcohol. Even small amounts can affect sleep architecture and next-day nervous system function. Caffeine gets the same scrutiny, both for total dose and timing.

Wiles gave one clinical example that stands out because it is so specific. When people come into his clinic drinking 4, 5, 6, or 7 cups of coffee a day, getting them down to 1 or 2 cups can materially change how their nervous system behaves.

"We'll see 20%, 30% increases in heart rate variability just by that adjustment in and of itself."

He does not stop at food and stimulants. Wiles also looks at relationship stress, work stress, and worldview. Those factors are often treated as too soft to matter, but they can change recovery just as clearly as sleep debt or late caffeine. This is where tools like the WHOOP Journal can help people test patterns around stress styles and repeated habit loops.

What you should take away

• Baseline HRV is shaped by fitness, sleep, food, stimulants, relationships, and mindset.
• Sleep quality and sleep quantity are foundational inputs for nervous system balance.
• Alcohol can affect sleep architecture and HRV even at low doses.
• Reducing high caffeine intake can improve HRV in a measurable way.

If you want to hear Wiles unpack caffeine, alcohol, sleep, and daily habits, listen to the full episode on Spotify

Why do relationships and perceived control change your stress response?

Relationships change your stress response because control is one of the nervous system's central concerns. Wiles says people become dysregulated when they feel unable to shape the outcome of a conversation, conflict, or ongoing relationship dynamic.

That applies to romantic relationships, friendships, family systems, and work. Wiles sees it especially often in high-performing executives who are used to directing outcomes. When another person pushes back, ignores expectations, or behaves unpredictably, the body can interpret that as threat. The nervous system then recruits more energy for defense, vigilance, or escape, even if the event is only a tense exchange or unresolved disagreement.

This is one reason subjective context matters next to objective metrics. If you log arguments, deadline pressure, or social strain in the WHOOP Journal, those notes can add meaning to changes in HRV, resting heart rate, Sleep, and Recovery. The goal is to spot the situations that repeatedly push your system into a state of overprotection.

Wiles traces the mechanism back to perceived control.

"When we feel like we're not in control within the context of a relationship [...] it strikes this evolutionary nerve for us and it ramps our system up."

His broader lesson is that nervous system regulation is partly biological and partly interpretive. People who see themselves as constantly cornered by outside forces often stay in a more defensive state. People who learn to notice the trigger, name it, and respond with skill usually regain flexibility faster.

What you should take away

• Relationship stress often shows up as a control problem before it shows up as an emotion problem.
• Work conflict, romantic conflict, and social uncertainty can all suppress recovery.
• Pairing journal context with HRV and resting heart rate can reveal recurring triggers.
• A nervous system that senses more agency usually returns to baseline faster.

If you want to hear Wiles go deeper on control, relationships, and stress adaptation, watch the full episode on YouTube

How can resonance frequency breathing train your nervous system?

Resonance frequency breathing can train your nervous system by giving you a pace of breathing that most strongly amplifies HRV and vagal activity. Wiles describes it as one of the clearest ways to show people that self-regulation is trainable.

He explains biofeedback in simple terms: use your biology as feedback while you practice a skill such as paced breathing. Instead of guessing whether a technique helped, you can watch physiology change in real time and adjust accordingly. That matters in a clinical setting because it turns self-regulation from an abstract idea into a visible process.

Wiles credits much of the modern protocol work to Rutgers University researcher Paul Lehrer's review of heart rate variability biofeedback. The basic finding is that people tend to have a breathing rate that best synchronizes the cardiovascular system and autonomic nervous system. Wiles says most people fall between 4.5 and 6.5 breaths per minute.

He gives a simple numerical example. Someone might start with a real-time HRV of 50 milliseconds, then move to 75 or 85 milliseconds after a minute or two of resonance breathing. Over time, repeated practice can change baseline function as well, not only the immediate response. In sport, Wiles has seen athletes use a few well-timed breaths before a serve or high-pressure moment to get into a calmer, more controlled state.

Wiles gives the range directly.

"Everybody has a resonance breathing rate as low as 4.5 breaths per minute to as high as 6.5 breaths per minute."

What you should take away

• Resonance frequency breathing is a biofeedback-based method for training autonomic control.
• Most people resonate somewhere between 4.5 and 6.5 breaths per minute.
• Real-time HRV can rise within minutes when the breathing pace matches the person.
• Repeated practice can improve both immediate regulation and baseline nervous system function.

What do mitochondria and hormesis have to do with stress resilience?

Mitochondria and hormesis matter because stress affects the body at a cellular level, and short, contained stressors can sometimes improve adaptation. Wiles frames this as a question of dose, timing, and recovery.

His first point is that chronic psychological and physiological stress can tax cellular function. He connects that burden to familiar markers such as HRV, resting heart rate, and overall recovery patterns. Overfeeding is one example. When calorie intake runs far above energy expenditure, Wiles sees that as a metabolic stressor that can work against healthy nervous system function.

At the same time, acute stress can be useful. Exercise is the simplest case. Training places stress on the system, but the short exposure can improve function if recovery is adequate. Wiles is especially interested in hormesis research around heat and cold exposure. He points to preliminary cold-water immersion research and sauna research suggesting that short exposures can trigger a rebound toward parasympathetic activity after the stressor ends.

One finding in particular caught his attention. In a cold plunge around 40 degrees, HRV dropped sharply during exposure, which fits a strong sympathetic response. Later, the pattern reversed.

"Around 30 to 45 minutes later [...] they didn't just return to baseline heart rate variability, they actually went above it for a period of time."

Wiles is careful on this topic. The evidence is promising, but the best protocol still depends on the person, the broader training load, and the reason for using heat or cold in the first place. That line of thinking also connects with other WHOOP conversations about training your brain and protecting recovery while still exposing the body to useful challenge.

What you should take away

• Chronic stress can affect nervous system function at a cellular level.
• Acute stressors such as exercise, heat, and cold may support adaptation when the dose is controlled.
• Overfeeding can act as a metabolic stressor that works against recovery.
• Cold and sauna research is promising, but protocol details still need more study.

The bottom line

• HRV can serve as a practical signal of how your nervous system is handling both physical and psychological stress.
• A lower HRV often reflects an active stress response and reduced flexibility in the autonomic nervous system.
• Sleep quality, sleep quantity, fitness, caffeine, alcohol, meal timing, and relationships all shape nervous system balance.
• Perceived control inside relationships and work can change recovery as clearly as many physical behaviors do.
• Resonance frequency breathing gives people a trainable way to raise HRV in real time and practice self-regulation.
• Most people resonate between 4.5 and 6.5 breaths per minute, which is slower than normal conversational breathing.
• Acute stressors such as exercise, heat, and cold may improve adaptation when recovery is present and dose is appropriate.
• The most useful stress metric is the one that helps you connect daily context with a repeatable action.

Frequently asked questions about things discussed in this episode

How does WHOOP measure HRV for nervous system insights?

WHOOP measures HRV during sleep, which gives a stable overnight view of autonomic nervous system activity from day to day. Your HRV trend is most useful when compared against your own baseline rather than someone else's number.

What does WHOOP do for tracking stress-related changes in recovery?

WHOOP shows stress-related changes through patterns across HRV, resting heart rate, Sleep, and Recovery. Your trends become more useful when you compare lower-recovery days with context such as poor sleep, alcohol, travel, conflict, or heavy workload.

How does WHOOP help you spot whether caffeine or alcohol is affecting HRV?

WHOOP helps you spot behavior effects when you log habits consistently and then compare those entries against Recovery and HRV trends. Your Journal entries can reveal whether late caffeine, alcohol, or late meals line up with worse nights and lower next-day readiness.

What does WHOOP show about sleep and nervous system regulation?

WHOOP shows that sleep is one of the strongest inputs into nervous system regulation because poor sleep often coincides with lower HRV and higher resting heart rate. Your Sleep data gives the nightly context that helps explain why recovery may feel harder the next day.

How can WHOOP help you practice resonance frequency breathing or self-regulation?

WHOOP can support self-regulation practice by showing whether a breathing session or pre-performance routine changes your physiological trends over time. Your data can confirm whether a consistent breathing habit is helping recovery, sleep quality, or next-day readiness.

What does WHOOP track that can show whether a cold plunge or sauna changed your response?

WHOOP tracks the downstream markers that can reflect how your body responded to a cold plunge or sauna, including HRV, resting heart rate, Sleep, and Recovery. Your best read comes from repeating the same exposure, logging it, and comparing the next several hours and next morning against baseline.

Seeing HRV, resting heart rate, Sleep, Recovery, and journal context together can turn nervous system regulation from a vague goal into a daily practice you can actually monitor.