Physiology First: Navigating a “Red Light” Morning with AlphaHRV

 

 

Physiology First: My Red Light Recovery Ride

This morning was a masterclass in why I apply a Physiology First framework to every session, looking at the internal engine before I look at the wattage. Between a late meal and the devastating news about my friend Murray being struck by a motorist—suffering a serious brain bleed—my autonomic nervous system was in a state of high alert.

My Morning Prognosis: Red Light

The metrics were undeniable. A Body Battery recharge of only +36 and an HRV Stress score of 75 indicated massive sympathetic dominance. Normally, this is a “No-Go” day. However, for my mental health and to maintain my commitment to the community, I elected for a strict recovery ride. This approach builds on the principles I discussed in my previous post, The Power Illusion.

Murray Wilmerding in cycling kit, smiling outdoors during a ride around Lake Tahoe in 2025.
Murray during our loop around Lake Tahoe in September 2025—a day defined by the joy of the ride and the strength of the engine.

 

Murray and Cynthia in the kitchen smiling while posing with two dogs during a dinner visit.
Murray and Cynthia with the dogs at dinner that same night—the real-world heart behind the physiological data we track every day.

 

Physiology First sleep metrics showing a 74 Fair score and a +36 Body Battery recharge.
Sunday night metrics: A ‘Fair’ score with a meager +36 Body Battery recharge—the first signal in the Physiology First protocol to down-regulate intensity.

 

Applying Physiology First via the Rogers Protocol

To ensure this ride didn’t deepen the deficit, I anchored the effort to the latest research from Dr. Bruce Rogers. While the standard VT1 is often set at an Alpha1 of 0.75, I utilized a custom approach to define my personalized “safety midpoint” based on the day’s peak autonomic state.

Physiology First HRV Stress test score of 75 showing high sympathetic strain on a Garmin wearable.
The physiological signal: A morning HRV Stress score of 75 is a definitive “Red Light” in the Physiology First protocol, confirming the body is in a state of high autonomic alert.

Using the formula HRVT-1c = (Peak Alpha + 0.5) / 2, I established a precise threshold. With a peak Alpha1 of 1.97 during the initial “vagal bounce” phase of the ride, my recovery floor for today was set at 1.235.

Reference: Improving the HRVT1 agreement – Dr. Bruce Rogers (IJSPP 10/2024)

The Physiology First Data: 64 Minutes of Autonomic Safety

Metric Value (Alpha1 ≥ 1.235)
Time in Zone 64 Minutes
Average Heart Rate 126 bpm (±3)
Average Power 159 Watts
Respiration Rate (AlphaHRV) 25 bpm
RR-A1 Ratio 0.29
Average SmO2 37.4%
Minimum SmO2 13.4%
A detailed chart plotting Alpha1, RR-a1, Heart Rate, and Power over time for a cycling recovery ride.
Anchoring to the internal engine: Maintaining Alpha1 above 1.235 and Heart Rate below 137 bpm to ensure true autonomic recovery.

Physiology First Analysis: Smoothed Power (30s) and RR-a1 (10s) relative to the 1.235 Alpha floor and 137 bpm HR ceiling.

Conclusion: Defending My Baseline

I didn’t ride today to get faster; I rode to stay grounded. When the overnight metrics and life events flash a “Red Light,” the temptation is to either skip the work or “ride off the stress” with too much intensity. By using AlphaHRV and SmO2 as real-time biofeedback, I turned a recovery ride into a session of active parasympathetic meditation.

The wattage was low, but the Physiology First victory was high. Today was about defending my baseline so I can be there for my clients and for Murray. One breath at a time.


Official Online Bike Coach logo representing the Physiology First cycling coaching framework and data analysis expertise.
Online Bike Coach: Physiology First.

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