Take It Easy: Too Much Exercise Frazzles the Vagus Nerve

Bettering bodily health requires placing stress in your system throughout vigorous exercises. However the quest for peak efficiency typically backfires—the psychophysiological misery attributable to extreme train is not good for you. Discovering a “Goldilocks zone” the place your every day exercises put sufficient stress in your physique to enhance health with out overdoing it may be difficult.

For instance, after I was making an attempt to get in form for excessive occasions just like the Triple Ironman (7.2-mile swim, 336-mile bike, 78.6-mile run), the chance of harm and burnout was extraordinarily excessive. Monitoring fluctuations in my coronary heart charge variability (HRV) was a manner to verify I wasn’t overtraining.

The vagus nerve’s means to counteract the sympathetic nervous system’s fight-or-flight stress response is mirrored by greater HRV.

Along with maintaining tabs on how my nervous system responded to the day before today’s stress load through the use of HRV, I additionally stored tabs on day-to-day temper adjustments. By means of trial and error, it grew to become clear that if I used to be actually cranky and in a foul temper the morning after an intense coaching session, it meant I used to be on the verge of getting burned out from overtraining and wanted to take it simple for a day or two.

As a retired extreme-distance athlete, I do know from lived expertise that doing an excessive amount of train could be dangerous to your psychological and bodily well-being. Overtraining is each endurance athlete’s Achilles heel. It is really easy for one’s ardour for sports activities and competitors to grow to be train fanaticism, which regularly results in accidents or overwhelming psychological misery.

Overtraining, Low HRV, and Destructive Moods Go Hand in Hand

New analysis (Alfonso and Capdevila, 2022) from the Universitat Autònoma de Barcelona (UAB) in Spain offers us recent insights into the hyperlink between HRV, overtraining, and temper states. Their peer-reviewed findings have been revealed on March 30 within the PeerJ journal.

Carla Alfonso and Lluis Capdevila of UAB’s Laboratory of Sport Psychology discovered that if a motorbike exercise was very intense and put an excessive amount of stress on a bike owner’s physique, HRV plummeted the next morning. Alfonso and Capdevila additionally found that HRV ranges correlated with cyclists’ moods. Low HRV was correlated with destructive temper states; greater HRV was related to higher temper states.

“The target of the analysis was to discover the relation amongst three features: coaching, coronary heart charge variability, and temper,” Alfonso mentioned in a information launch. “With this research, we aimed to know when an athlete should relaxation, as a result of their system is saturated, and when an athlete can prepare, with kind of depth, as a result of their physique is able to assimilate the coaching load.”

The primary takeaway from this pilot research is that HRV and temper states appear to rise and fall in tandem. For instance, if a “weekend warrior” overdoes it on Sunday, odds are that they’re going to be cranky or in a foul temper Monday morning. Destructive temper states the day after placing an excessive amount of stress in your physique by overtraining correlate with decrease HRV.

This illustration reveals the human mind and “wandering” vagus nerve. Within the Twenties, a German-born researcher named Otto Loewi found that electrically stimulating the vagus nerve launched a parasympathetic substance that slows heartbeats and calms the nervous system. Immediately, we consult with this vagus substance as acetylcholine. Loewi known as it “vagusstoff.”

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Coronary heart Fee Variability Displays the Vagus Nerve’s Response to Stress

The vagus nerve secretes an inhibitory substance straight onto the guts, slowing it down. Coronary heart charge variability measures how successfully vagus nerve exercise is creating wholesome fluctuations between heartbeats. Larger HRV signifies that the physique has a sturdy means to tolerate and get better from stress. Conversely, decrease HRV implies that the vagus nerve is “frazzled” and is not successfully inhibiting the sympathetic nervous system’s fight-or-flight response, which revs up heartbeats and displays a decrease stress tolerance.

Otto Loewi gained a Nobel Prize in 1936 for his discovery that stimulating the vagus nerve releases an inhibitory substance that slows heartbeats and calms the nervous system.

Within the Nineteen Seventies, my neurosurgeon father taught me about Loewi’s vagus nerve analysis within the context of sustaining grace below strain. My dad knew that “vagusstoff” was launched throughout the exhalation part of the respiratory cycle. So, he used respiratory workout routines to remain calm throughout mind surgical procedure and on the tennis courtroom. (See “How ‘Vagusstoff’ (Vagus Nerve Substance) Calms Us Down.”)

After I was a younger tennis participant, Dad coached me to take a fast inhalation by means of my nostril adopted by an extended, sluggish exhalation by means of pursed lips to calm my nerves earlier than each serve. A latest research discovered that one five-minute session of deep, slow-breathing train (4 seconds in, six seconds out) will increase vagal tone and reduces anxiousness. Personally, I want an inhale-exhale ratio of four-second inhalations adopted by eight-second exhalations.

On the premise of evidence-based analysis and lived expertise, I do know that longer exhalations are a straightforward technique to hack your vagus nerve by triggering the discharge of vagusstoff. However, I additionally perceive that the calming impact of those respiratory workout routines tends to be short-lived.

When the sympathetic nervous system is overstimulated by an excessive amount of train, diaphragmatic respiratory is only a bandage that provides you momentary reduction. Relaxation is the most effective treatment for giving your vagus nerve and parasympathetic system an opportunity to bounce again.

To Sum Up: Extreme Train Reduces Vagus Nerve Tone as Listed by Low HRV

HRV is an indispensable device for maintaining tabs on how your vagus nerve responds to exercise-induced stress and making certain that you do not overtrain. Low HRV signifies that the fight-or-flight mechanisms of your sympathetic nervous system are in hyperdrive and that vagal tone is weak. Conversely, greater HRV reveals that vagus nerve exercise is powerful and that your parasympathetic nervous system is dealing with stress effectively.

The most recent analysis (2022) on HRV and overtraining reaffirms that low HRV is a warning signal that your vagus nerve could also be “frazzled” from an excessive amount of psychophysiological misery. If you do not have entry to an HRV monitor, experiencing destructive moods the day after exercising vigorously could also be an indication that you must take it simple for the following 24 hours and provides your system time to recuperate.