Editorial Standards
How We Select Studies
We do not select studies because they confirm what we already believe. Our selection criteria are applied before we decide to run an issue:
- Study design quality - systematic reviews and RCTs are weighted above observational data
- Relevance to the mechanism of non-restorative sleep, not just sleep onset or sleep duration
- Biological plausibility - the mechanism must be coherent with what we know about sleep physiology
- Ingredient overlap with the Night Reboot formula is noted where applicable, but is not a selection criterion
- Limitations worth surfacing honestly to our readers, even when the finding supports our thesis
Every entry includes the full citation, the exact effect size with confidence interval where available, the study's limitations, and a clear verdict. We do not say "proven" when the evidence says "promising."
That is the mechanism the Digest investigates. Not sedation. Not sleep hygiene. The physiological conditions under which genuine recovery becomes biologically accessible - for the nervous system, for the body, and for the brain that has to function the next day.
Evidence Rating System
How We Rate the Evidence
Every study receives one of three ratings:
Robust, consistent signal across multiple well-designed studies. We are confident in the direction of the evidence.
A good signal from peer-reviewed research that needs replication or larger samples before we call it settled.
Pilot data, small sample sizes, or a single study with major limitations. Worth watching. Not worth citing as fact.
We apply these ratings before we decide how strongly to present a finding. If a study supports the position we hold but the evidence is weak, we say so. That is not self-sabotage - it is the only way to build a publication readers can actually trust.
Get the Digest every Monday
One email a week. Three to five peer-reviewed sleep papers, each rated Established, Promising, or Too Early, with the effect sizes, the limitations, and what each one changes for you.
We publish the papers that go against us as readily as the ones that support us. No sales sequence, no daily wellness tips, unsubscribe in one click.
Published by Zandra Life Sciences Pvt. Ltd., makers of REINCARN Night Reboot. Commercial interest disclosed on every issue. · RSS feed
Published Issues
Issues
13 Studies, 782 Women: Mindful Movement Significantly Improved Sleep Quality
A 2026 meta-analysis of 13 RCTs found that yoga, mindfulness, and Pilates significantly improved PSQI sleep quality scores in perinatal women (MD = -2.63, 95% CI -3.36 to -1.90). The mechanism -- parasympathetic activation - is not unique to pregnancy.
Your Late Nights Are Doing to You What Night Shifts Do to Workers
A 2026 systematic review of 11 studies finds irregular sleep schedules trigger the same circadian disruption as night shift work. Here is what the science means for your recovery tonight.
Disrupted Sleep Architecture, Not Just Duration, Consistently Linked to Cognitive Decline
A 2026 systematic review finds that circadian dysregulation, fragmented sleep, poor sleep efficiency, and misaligned melatonin timing all track with higher risk of mild cognitive impairment and dementia. Getting 7 hours is not enough if those hours are poorly structured.
Melatonin and Cardiac Arrhythmia: What Three Cases and a 2026 Systematic Review Tell Us
A 2026 systematic review in Pharmaceuticals documents 4 cases of cardiac arrhythmias temporally associated with melatonin supplementation (1-10 mg/day), resolving after stopping. Causality not established. Evidence quality: Very Low. This is one reason Night Reboot is melatonin-free.
Mindfulness Improved Sleep in Adults With Cognitive Decline Across 7 Studies
A systematic review and meta-analysis of 7 studies (434 adults, ages 56-87) found meditation-based interventions produced a meaningful improvement in sleep quality (Hedges’ g = 0.75). The mechanism: quieting the HPA stress axis and shifting brain activity toward alpha waves. Verdict: Promising.
One Night of Restricted Sleep Erased the Metabolic Benefits of Exercise
A 2026 systematic review of 7,715 adults found that a single night of restricted sleep was sufficient to abolish the triglyceride-lowering effect of prior exercise. The mechanism runs through cortisol dysregulation, SNS activation, and inflammatory cytokines. Verdict: Promising.
People with More Daytime Light Exposure Had 3x Higher Odds of Good Sleep Quality
A 2026 RCT in the Journal of Pineal Research (202 older adults, 3 EU cities) found that higher naturalistic daytime light exposure was associated with 3x higher odds of good sleep quality (OR = 3.00, 95% CI: 1.16-8.11, p = 0.03). Timing mattered: starting light supplementation before 11 AM reduced sleep-wake fragmentation. Verdict: Promising.
Who Writes This
About the Digest
Hiya Aidasani
M.Tech Medical Biotechnology, IIT Hyderabad
We have a simple editorial rule: if we cannot say something clearly and honestly, we do not say it. That applies to the research we cover and to the product this digest connects to.
That conviction is why we built this digest - and why we built the product it connects to. High performers deserve a publication that holds itself to the same standard they hold their training, nutrition, and work. The Digest is that publication.
Frequently Asked Questions
Questions About the Digest
What is the Sleep Performance Digest?
The Sleep Performance Digest is a weekly research publication by the Reincarn Science Team at Zandra Life Sciences Pvt. Ltd. Each issue summarises one peer-reviewed study on sleep science and recovery, with the evidence rated Established, Promising, or Too Early - and honest disclosure of each study's limitations. It is published for informational purposes only and does not constitute medical advice.
Who writes the Sleep Performance Digest?
Research analysis is produced by the Reincarn Science Team, including Hiya Aidasani (Research Collaborator). Editorial oversight is provided by Arun Menon, Founder of Zandra Life Sciences Pvt. Ltd. Every entry is reviewed for factual accuracy before publication. Corrections can be sent to arun@zandralifesciences.com.
What is the difference between sleep duration and sleep recovery?
Sleep duration is the hours spent unconscious. Recovery is the physiological restoration that happens during specific stages - primarily deep slow-wave sleep (SWS) and REM. According to CDC NCHS Data Brief No. 559 (April 2026), 45% of adults do not wake up well-rested despite sleeping adequate hours. The Digest investigates the mechanisms behind this gap: why some bodies restore and others do not, despite the same time in bed.
How does the Digest rate research evidence?
Three levels. Established: robust, consistent evidence across multiple well-designed studies. Promising: a good signal that needs replication or larger samples. Too Early: pilot data or small studies with major limitations - worth watching, not worth citing as fact. These ratings are assigned before we decide how strongly to present a finding.
Is the Digest affiliated with Reincarn Night Reboot?
Yes. The Sleep Performance Digest is published by Zandra Life Sciences Pvt. Ltd., makers of Reincarn Night Reboot - India's First Sleep Performance Supplement. Where a study relates to ingredients in the Night Reboot formula, we note the connection. Studies are selected based on quality and relevance to sleep recovery mechanisms, not on whether they support the product. Affiliated-publisher disclosure is included in every issue footer.
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