Longevity & Market Fatigue
March fatigue as a phenomenon
March fatigue (also called spring fatigue) is a temporary period in which people, during the transition from winter to spring, may feel less energetic, slower, or “not quite sharp.” It is not a uniform, clearly delineated condition, but rather a cluster of complaints that often coincides with changes in light, sleep, and daily routine. In the scientific literature, there is, however, a lot of knowledge about seasonal influences on sleep, rhythm, and mood, but far less about “spring fatigue” as a separate diagnosis. [1]
An important distinction: fatigue is a symptom, not a final diagnosis. In general practice, people often work with the idea of physiological fatigue (a normal response to an imbalance between load and recovery) versus fatigue that fits an underlying medical or psychological cause. March fatigue, as a working term, usually falls into that first category: more “need for recovery” than “illness.” [2]
What March fatigue is not: it is not the same as depression, burnout, or ME/CFS, and you cannot reliably “self-diagnose” it based on one week of low energy. If fatigue persists for a long time, clearly increases, it is wise to discuss this with a doctor. Dutch public information also emphasizes that targeted testing is often only useful if, in addition to fatigue, there are other symptoms or indications. [3] [4]
Why especially during seasonal transitions
Light as a biological “control knob”
The human body is strongly tuned to the 24-hour cycle. Light , is also the most powerful external cue (zeitgeber) that helps “synchronize” our circadian rhythm with the environment. When day length, sunrise, and evening light change, your biological clock receives different input than a few weeks earlier. That requires adjustment—sometimes subtle, sometimes noticeable. [5]
A practical nuance: not only more light, but especially the timing of light exposure matters. A large systematic review on light and sleep in adults shows that brighter morning light more often correlates with sleep shifts toward “earlier” and (subjectively) better sleep, while brighter evening light more often correlates with a shift toward “later” and (subjectively) poorer sleep. [6]
In addition, evening and nighttime light can suppress melatonin. Research on evening light (including in realistic settings) describes that evening/night light can influence melatonin rhythms and increase alertness, which can disrupt sleep pressure if this happens structurally. [7]
Seasonal patterns in sleep: small, but consistent
Analysis of large datasets shows that seasonal changes are associated with small but statistically significant shifts in sleep patterns. In a large-scale longitudinal study, people were found to wake up slightly earlier and sleep slightly less on average in spring than in winter. [8] These differences are generally modest in size, but illustrate that our sleep-wake rhythm is sensitive to changes in daylight and seasonal environmental factors.
A seasonal pattern has also been described in clinical sleep data: in an analysis of polysomnographies from a sleep clinic, total sleep duration was on average higher in winter and lower in spring. With differences that can be on the order of tens of minutes between winter and spring/early summer. The population is specific, so this cannot be translated one-to-one to “everyone”, but it does support the idea that spring can be a period of sleep shift. [9]
Chronotype and sensitivity to change
Not everyone responds the same way. Chronotype (more of a morning person or an evening person) is related to when you feel cognitively and physically at your best and how your internal clock is “phased” relative to social time. There is evidence that chronotype can change with seasonal changes, probably due to differences in light exposure, with people responding differently to changes in day length. [10]
Late March: the clock change as an extra “micro-shock”
In many European countries, the transition to daylight saving time takes place at the end of March. That is not the only factor, but it can act as an additional trigger on top of the seasonal change. A systematic review in Sleep Medicine Reviews concludes that the transition to daylight saving time is often associated with adverse effects on sleep duration/quality and increased sleepiness, with “evening types” potentially being relatively vulnerable. [11]
In a large analysis within the Canadian Longitudinal Study on Aging, circadian misalignment (as with jet lag, shift work, and the clock change) is also explicitly linked to sleep disruption, neurocognitive effects, fatigue, and mood changes, as a conceptual framework, not as “proof” that every individual complaint in March comes from this. [12]
Allergies as an often underestimated spring factor
Spring fatigue isn’t always about circadian biology. If you have allergic rhinitis (hay fever), there is strong evidence that it is associated with poorer sleep and sleep disruption, and thus indirectly also with daytime fatigue. A systematic review and meta-analysis of observational studies found associations between allergic rhinitis and sleep duration/problems, which plausibly contributes to “I’m tired in spring”. [13]
A longevity perspective on energy and resilience
Longevity is primarily about healthspan[14]: a long period of good physical and mental function, capacity to recover, and autonomy, not “living as long as possible” as a separate goal. [15] From that framework, March fatigue is interesting because it often touches on three layers that are also central to healthy aging:
Circadian rhythm
With increasing age, sleep architecture, circadian amplitude, and timing often change (for example, more fragmentation, a different phase preference). Reviews on “circadian aging” describe that weakening circadian function is linked to broader domains such as sleep, metabolic regulation, cognitive processes, and inflammatory status—exactly the domains in which people also experience “energy”. [16]
Energy metabolism
Energy metabolism is about how your body converts fuels (carbohydrates, fats, amino acids) into usable energy and how supply and demand stay balanced. Insufficient sleep and circadian misalignment are seen in major reviews as metabolic stressors: they affect, among other things, energy intake, expenditure, and hormonal regulation. This is not a “March-specific” mechanism, but it is a lens for understanding why a period with a rhythm shift can subjectively feel more tiring. [17]
Mitochondrial function
Mitochondria play a central role in cellular energy production and are abundant in energy-intensive tissues such as muscles. Reviews on skeletal muscle aging describe that age can be accompanied by changes in mitochondrial biogenesis, dynamics, and quality control (such as mitophagy), which is associated with declines in muscle function and physical resilience in the context of sarcopenia. [18]
The practical translation for March fatigue is not: “your mitochondria suddenly work worse in March”, but: a body with less recovery reserve (due to age, stress, poor sleep, inactivity, energy deficits, or illness) can “feel” a period of rhythm and routine change more clearly. This interpretation also fits the broad evidence that lifestyle factors (sleep, physical activity, nutrition, mental health, social context) are linked to healthy aging and functioning. [19]
Evidence-based strategies to support energy and recovery
Below are no “quick fixes”, but interventions with a solid scientific basis that align with autonomy and resilience.
Rhythm first: sleep as the foundation
For most adults, ≥7 hours of sleep per night is associated with better health and functioning; this is set out in a joint consensus recommendation by the American Academy of Sleep Medicine[20] and the Sleep Research Society[21]. [22]
In March (and especially around daylight saving time), a useful principle is: first stabilize your timing, and only then optimize “biohacks.” That means: a fixed wake-up time (also on weekends), and a bedtime that moves realistically with it so you get enough sleep. In population studies, circadian misalignment is seen precisely as a factor that can disrupt sleep and functioning. [23]
Light hygiene: more daylight, less late light
The best-supported light intervention is often surprisingly simple: morning light. A systematic review on light in relation to sleep in adults shows that timing matters: brighter morning light is more often associated with favorable subjective sleep outcomes; brighter evening light is more often associated with unfavorable subjective sleep outcomes. [6]
Concretely, in practice that means: - try (if you can) to get outdoor light in the first part of the day; - dim brighter light late in the evening (living-room lighting, tablet/phone close to your face, working behind a bright screen), especially if you notice it’s getting harder to fall asleep.
That evening light can affect melatonin and alertness has also been described in experimental settings, which strengthens the plausibility of “calm evenings, active mornings.” [24]
Physical activity: the most reliable “energy tool” in the long term
For longevity, physical activity is one of the best-supported pillars. The World Health Organization[25] advises adults (including 65+) to do 150–300 minutes of moderate-intensity aerobic activity per week or 75–150 minutes of vigorous activity, plus muscle-strengthening activities. [26]
From the perspective of energy metabolism and mitochondria, the logic is clear: training can support mitochondrial capacity and muscle function, and reviews describe that both aerobic and strength stimuli can partly slow age-related decline, provided the program is appropriate and sustainable. [27]
Practically speaking, in March:
- Choose a low-threshold base (daily walking).
- Add strength training 2–3× per week (full body, major muscle groups).
- If you’re already tired: increase volume gradually; overloading without recovery can actually worsen fatigue.
This also fits with the medical view of physiological fatigue as an imbalance between exertion and recovery. [28]
Nutrition and timing: support without overcomplicating
The core of March fatigue is often: “my system is running just a bit differently.” Then it helps to use food primarily for stability: eat regularly, get enough protein, drink enough fluids, and don’t eat a heavy meal too late if your sleep is fragile. In the broader context, large reviews describe that insufficient sleep and circadian misalignment are associated with disrupted metabolic regulation and eating behavior, which may explain why people experience more cravings or eat less “steadily” when their rhythm changes. [17]
Anyone who wants to experiment in a targeted way can also look at consistent mealtimes: circadian regulation and metabolism are intertwined and timing seems relevant, although the field is still developing and highly context-dependent. [29]
Stress, mental load, and “cognitive fatigue”
An energy dip in March is sometimes mainly mental: more stimuli, more plans, more “musts” once it gets lighter. In general, there is good evidence that circadian disruption and sleep deprivation are linked to poorer cognitive performance, more sleepiness, and a lower mood. [30]
A calm, effective intervention then isn’t a supplement, but removing friction:
- 1 fixed place for plans/appointments,
- one evening a week “low-stimulus” as a recovery anchor,
- a short daylight moment + a calm walk as a “reset” (light + movement is a powerful combination in circadian biology). [31]
NAD+ boosters and supplements in context
What is NAD+ and why is there interest?
NAD⁺ (nicotinamide adenine dinucleotide) is a coenzyme involved in redox reactions and energy metabolism (including in mitochondrial processes) and is also connected to DNA repair and the cellular stress response. The concept of “NAD⁺The concept of “NAD-boosting” comes from ageing biology and preclinical models, in which NAD⁺NAD+-augmentation regularly shows beneficial effects on metabolic and mitochondrial markers. [33]
Can NAD+ boosters help with energy or fatigue?
Fatigue is rarely just one thing. It’s not a switch that is simply “on” or “off.” Especially after the age of forty, many people notice their energy subtly changes. Not necessarily due to illness, but due to a combination of sleep quality, stress load, hormonal shifts, and changes in cellular energy metabolism.
In that context, the question is increasingly being asked whether NAD⁺-boosters may help.
When we talk about NAD⁺By NAD-boosters, we generally mean substances such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). These are precursors of NAD⁺, a coenzyme essential for energy production in the mitochondria, the “powerhouses” of our cells.
Why NAD⁺ is fundamental for energy
NAD⁺ plays a central role in processes directly linked to cellular energy production. It is involved in the production of ATP in the mitochondria, supports DNA repair mechanisms, and activates enzyme families such as sirtuins that are involved in stress responses and metabolic regulation.
What’s important to understand: NAD⁺-support does not work like a stimulant. It doesn’t give an immediate “kick” like caffeine. It supports an underlying biological process that can gradually become less efficient with age. That decline in NAD⁺availability is well documented in the literature and is considered one of the hallmarks of cellular aging.
When that system is supported, it can contribute to more efficient energy metabolism at the cellular level.
Circadian regulation of NAD⁺
A less well-known but biologically important mechanism is that the circadian system is also closely linked to the regulation of NAD⁺.
NAD⁺ (nicotinamide adenine dinucleotide) is an essential coenzyme involved in cellular energy production, mitochondrial function, and DNA repair. What is often less well known is that NAD⁺ levels themselves also follow a circadian pattern.
Research shows that the central circadian clock, via genes such as CLOCK and BMAL1, regulates the activity of the enzyme NAMPT, a key enzyme in the so-called NAD⁺ salvage pathway. As a result, NAD⁺ levels fluctuate during the day, often with higher activity during the active phase of the circadian rhythm. [32]
This relationship also works in both directions. NAD⁺ is required for the activity of sirtuins, especially SIRT1, enzymes that in turn are involved in regulating circadian gene expression and metabolic processes. The circadian system and NAD⁺ metabolism thus form a biological feedback mechanism that links energy metabolism, recovery processes, and daily rhythms. [33]
From this perspective, it is understandable that factors influencing the circadian rhythm—such as light exposure, sleep quality, physical activity, and meal timing—are also indirectly linked to cellular energy processes.
What do human studies show?
For NR, randomized, double-blind cross-over studies in middle-aged and older adults have shown that NAD⁺metabolism is reliably increased, with a favorable safety profile [36]. This means the substance truly activates the intended biological system, so-called target engagement.
The same broadly applies to NMN. In multiple studies in older men and healthy middle-aged adults, an increase was observed in blood NAD⁺ or related metabolites. Here too, supplementation over weeks to months was well tolerated [37] .
A PRISMA-guided systematic review up to October 2025 concludes that NR and NMN consistently achieve their biological target in humans, namely increasing NAD-related biomarkers [38]. In multiple human studies, targeted improvements are seen in metabolic and functional parameters related to energy metabolism and muscle function. This reflects NMN’s underlying mechanism: increasing NAD⁺, a crucial cofactor for mitochondrial energy production and cellular repair processes. Precisely because NMN works at this fundamental level, we see effects that align with structural support rather than temporary symptom relief.
What is clear, however, is that NAD⁺-boosters support processes that are fundamentally involved in energy production and recovery. From a longevity perspective, that’s a relevant angle. Not because it offers a quick fix, but because it intervenes in a biological system that is central to healthy aging.
NAD⁺-support within a broader strategy
At Enduravita, we never see supplements as a replacement for lifestyle. The foundation of energy and resilience lies in consistent sleep, a stable circadian rhythm, regular strength and endurance training, metabolic health, and stress regulation. Systematic reviews on healthy aging repeatedly show that lifestyle interventions are decisive for functioning, resilience, and quality of life [19].
Within that foundation, targeted interventions can be meaningful. NR and NMN support the availability of NAD⁺, a molecule involved in mitochondrial function and cellular repair processes [35]. Resveratrol is linked in mechanistic literature to pathways such as AMPK–SIRT1–PGC-1α, which are also associated with energy metabolism and stress adaptation [36]. TMG (betaine) contributes to normal homocysteine metabolism. The beneficial effect occurs with a daily intake of 1.5 g betaine [37]. TMG is often used in combination with NMN.
These substances are not miracle cures. They are potential links within a bigger picture: supporting cellular processes involved in energy, recovery, and metabolic resilience.
A rational approach
Anyone considering NAD⁺-support, is best served by approaching this as a personal experiment with clear goals. Think of parameters such as sleep quality, morning energy, or training recovery, evaluated over a defined period. If you use medication, are pregnant, or have a chronic condition, it’s wise to coordinate beforehand with a doctor or medical professional.
The essence is clear: NR and NMN demonstrably increase NAD⁺-related biomarkers. This is biochemically substantiated.
Ultimately, longevity isn’t about a quick energy boost, but about supporting the systems that keep your body resilient in the long term.
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