Written by the Nuvirox Research Team
Key points
- Volunteer firefighters carry a full-time job or family life on top of unpredictable, adrenaline-heavy calls — that stacking, not any single call, is what wears people down.
- Repeated middle-of-the-night pages fragment deep sleep even on nights with no call at all, because the body stays primed to wake.
- NAD+ precursor research shows reliable increases in blood NAD+, but human trials on fatigue and recovery outcomes are still mixed.
Short answer: yes, and it's a specific, stacking kind of tired. It's not just physical exertion from fighting fires — it's the combination of a day job, unpredictable pages at any hour, and a nervous system that has to be ready to go from asleep to fully alert in under two minutes.
Why does the pager itself wear you out, even on quiet nights?
Because your nervous system doesn't know in advance which nights will be quiet. Anticipatory arousal — the body staying primed for a possible page — keeps sleep lighter and more fragmented even when the pager never goes off. Sleep researchers call this a hypervigilance pattern: your brain trades deep, restorative sleep stages for a lighter, more easily-interrupted state. Do that for years and the sleep debt doesn't reset on your day off; it accumulates.
What does the actual call do to your body?
A structure fire or a serious MVA triggers a real adrenaline and cortisol surge, useful in the moment for strength and focus, but expensive afterward. Once the adrenaline clears, most people hit a physiological trough — heavy limbs, foggy thinking, sometimes irritability — that can last hours. If that call happens at 2 a.m. and you're expected at your day job at 8 a.m., you're running the rest of the day on a body that's still metabolically settling down from a stress response, not on a full night's sleep.
Does the exhaustion actually change over a fire season, or stay constant?
Most volunteers describe it as cumulative rather than steady. A single busy week is usually manageable on its own, but consecutive weeks with multiple overnight calls, layered on top of a normal work and family schedule, tend to produce a slower-building fatigue that doesn't fully resolve on a single day off. That's consistent with how sleep debt is generally understood: it doesn't reset to zero with one good night, it's paid down gradually, and a department's call volume during a given stretch can outpace anyone's ability to pay it down in real time. This is part of why fatigue-related concerns tend to cluster during unusually active periods rather than showing up evenly year-round, and why some departments have started paying closer attention to call rotation during those stretches specifically.
What the human research on NAD+ precursors actually shows
The research on NAD+ precursors and fatigue doesn't map onto volunteer firefighting specifically — nobody has run a trial on fire crews — but it's worth being clear about what the human data on the underlying pathway actually shows.
Study 1: In an 8-week randomized, double-blind, placebo-controlled trial in healthy overweight adults (n≈140 screened, ~30–34 per arm analyzed), 100, 300, and 1,000 mg/day doses of nicotinamide riboside raised whole-blood NAD+ by 22%, 51%, and 142% respectively within two weeks, with the increase sustained through the full eight weeks and no meaningful difference in adverse events versus placebo.
Study snapshot — Conze D, Brenner C, Kruger CL...
Design: An 8-week randomized
N: ~140 enrolled
Duration: 8 weeks
Dose: 100–1,000 mg/day NR
Study 2: In a randomized, placebo-controlled trial in 32 elderly adults (55–80) undergoing an induced muscle-injury protocol, NRPT (1,000 mg NR + 200 mg PT/day) raised whole-blood NAD+ as expected, but showed no measurable benefit on muscle strength recovery, force development, or tissue-damage markers compared with placebo over the 30 days after injury.
Study snapshot — Jensen JB, Dollerup OL, Møller AB, et al...
Design: A randomized
N: 32
Duration: 45 days
Dose: 1,000 mg NR + 200 mg PT/day
What NAD+ Restore won't do about volunteer-related fatigue
NAD+ precursors are not a substitute for sleep, and no supplement will neutralize a genuine adrenaline crash or make a 2 a.m. structure fire feel like a full night's rest. If you're experiencing chest pain, unusual shortness of breath, or symptoms that don't resolve with rest, that's a conversation for a doctor, not a supplement aisle — cumulative fatigue in first responders has real cardiovascular stakes that deserve a clinical look, not a guess.
Trials showing NAD+ increases used 100–1,000 mg/day of nicotinamide riboside over 8 weeks or more; none were designed around acute recovery from a single stressful call. Given that the underlying research is about sustained supplementation, not single-dose recovery, it doesn't make sense to judge a NAD+ precursor by how a bad night after a call feels the next morning. A more reasonable evaluation window mirrors the trials themselves: several consecutive weeks that include a realistic mix of quiet stretches and busy call periods, since that's the timeframe over which any real physiological change would show up, if it shows up at all for a given person.
For more background, see what a NAD+ supplement actually does why NAD+ declines with age why home health aide work is so physically and emotionally draining why homesteading is so much more exhausting than it looks.
Frequently asked questions
Why am I exhausted the day after a call even if I got some sleep?
Sleep quantity isn't the whole story — sleep architecture matters. A call that spikes adrenaline and cortisol can suppress the deep and REM stages of whatever sleep you do get afterward, so eight hours in bed doesn't translate to eight hours of restorative sleep.
Does caffeine make this worse over time?
Leaning on caffeine to push through a post-call trough is common, but it can delay your body's return to a normal sleep-wake rhythm on subsequent nights, especially if used late in the day.
Is this just something I have to live with as a volunteer?
Some of it is structural — unpredictable calls are inherent to the role — but department-level shift and call-rotation practices, and your own recovery habits between calls, both make a measurable difference in how sustainable it feels.
How is this different from career firefighter fatigue?
Career crews at least have defined shift patterns to plan recovery around. Volunteers are layering fire calls on top of an already-full schedule with no equivalent recovery block, which is part of why the fatigue can feel less predictable and harder to plan for.
FROM NUVIROX
Why we formulated NAD+ Restore
NAD+ Restore is built around the same NAD+ precursor family studied in the human trials discussed above, paired with supporting compounds chosen for how they work alongside that pathway. The formula is currently being refined as we incorporate newer research, so we're intentionally not listing exact ingredient amounts here — what stays constant is the underlying formulation philosophy: precursor-first, dosed in ranges informed by published human research, without unnecessary filler ingredients.
Every order is backed by a 60-day money-back guarantee — long enough to actually evaluate it the way the research says you should.
Learn more about NAD+ Restore →The bottom line: The exhaustion is real and it's coming from a specific mechanism — a nervous system kept on standby plus a day job with no built-in recovery window — not from any single failure on your part. Protecting sleep between calls where you can, and treating recurring exhaustion as worth a doctor's attention rather than something to just push through, matters more than any supplement.
References
- Conze D, Brenner C, Kruger CL. Safety and metabolism of long-term administration of NIAGEN (nicotinamide riboside chloride) in a randomized, double-blind, placebo-controlled clinical trial of healthy overweight adults. Sci Rep. 2019;9:9772. PMID: 31278280.
- Jensen JB, Dollerup OL, Møller AB, et al. A randomized placebo-controlled trial of nicotinamide riboside and pterostilbene supplementation in experimental muscle injury in elderly individuals. JCI Insight. 2022;7(19):e158314.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.