Between screens, shared desks, and shifting bedtimes, a school year is a long stretch for a kid's immune system and attention span alike. Here's what the research actually says helps — and where the evidence is thinner than back-to-school marketing suggests.

Written by Vita Globe Editorial Team | Reviewed against peer-reviewed research and NIH/CDC guidance

Why a Long School Year Is Hard on Kids (and Teachers)

Anyone who has made it through a full school year recognizes the rhythm: a burst of energy in September, a dip around the holidays, and by February, a classroom running on fumes. Three things stack on top of each other over the course of a year — heavier screen use for schoolwork and review, close, shared physical space that spreads colds and flu efficiently, and bedtimes that quietly creep later as homework and activities pile up. None of these is a crisis on its own. The strain comes from all three running at once, for nine months straight, for kids and the adults teaching them.

Does Screen Time Really Matter? What the Guidance Actually Says

Between one-to-one devices, homework apps, and review tools used in class, most students spend a meaningful part of their day looking at a screen — and that's before evening homework starts. It's worth being precise about what the leading pediatric guidance actually recommends here, because it's changed.

The American Academy of Pediatrics no longer publishes fixed hour-by-hour screen time limits for school-age children. Its current position is direct: there "isn't enough evidence demonstrating a benefit from specific screen time limitation guidelines"^[3]. Instead of a countdown timer, the AAP's guidance focuses on the quality of media use — what a child is doing on a screen, not just how long — and on making sure screen use doesn't displace sleep, physical activity, and in-person interaction^[3].

In practice, that means the more useful question isn't "how many hours," but "what's getting pushed out." A screen-heavy homework night that still leaves room for a consistent bedtime and some movement is a very different thing from one that eats into both.

How Much Does Sleep Really Affect Grades and Behavior?

Of everything that affects how a student shows up to class — focus, mood, patience, how quickly new material sticks — sleep is the one the evidence supports most consistently, and it's also usually the first thing to slip during a busy stretch of the school year.

A 2025 systematic review in Clocks & Sleep pulled together 20 studies (from 99 screened) on sleep and development in children ages 6–12, published between 2019 and 2024. It found consistent associations between better sleep and stronger cognitive performance, better emotional regulation, and fewer behavioral problems — with several studies pointing to sleep as a link between heavy screen use and behavioral difficulties^[1]. The honest caveat: most of the underlying studies were cross-sectional and relied on self-reported sleep, so they show a strong association rather than definitive proof that fixing sleep alone fixes grades^[1]. That's a meaningfully more careful claim than "sleep makes kids smarter" — but a consistent bedtime remains one of the few habits with real evidence behind it, and it costs nothing to try.

Classroom Germs: What Actually Reduces Colds and Absences

Shared supplies, close desks, and a few dozen kids touching the same door handle make a classroom one of the most efficient places for illness to spread. The good news is that the single most effective, best-studied countermeasure is also the cheapest one.

According to the CDC, community handwashing education measurably reduces illness: respiratory infections (like colds) drop by 16–21% in the general population, and school absenteeism specifically tied to gastrointestinal illness drops by 29–57%^[2]. Handwashing works because it interrupts the two main ways germs spread in a classroom — hand-to-face contact and hand-to-surface-to-hand contact — and it requires no special products, just soap, running water, and about 20 seconds^[2].

This is worth stating plainly because it's easy to overlook in favor of more exciting-sounding interventions: no supplement, herbal or otherwise, has evidence anywhere near as strong as basic hand hygiene for reducing how often a classroom gets sick.

Elderberry for Immune Support: What the Evidence Shows

Elderberry (Sambucus nigra) has a long history of traditional use for colds and flu, and it's become a common back-to-school staple. Here's what controlled research actually shows — including where it falls short of the strongest claims made about it.

A 2016 randomized, placebo-controlled trial of 312 travelers found that the placebo group experienced significantly longer cold duration (117 vs. 57 total symptom-days, p=0.02) and higher average symptom severity scores (583 vs. 247, p=0.05) than the elderberry group, though the number of people who caught a cold at all didn't differ significantly between groups^[4]. A separate 2019 meta-analysis pooling randomized trials found a "large" effect on reducing upper respiratory symptoms overall — but the total pooled sample across all included trials was just 180 people, a genuinely small evidence base for a firm conclusion^[5].

The most balanced read comes from a 2021 systematic review that set out specifically to check for safety concerns (there was concern elderberry might overstimulate the immune system). Its conclusion: elderberry "may reduce the duration and severity of colds," and may reduce influenza duration, but "the evidence is uncertain" on both counts, while finding no evidence that it overstimulates the immune system or causes harm^[6]. NIH's National Center for Complementary and Integrative Health describes the research base similarly — "preliminary" — and adds one safety note worth knowing for families: raw or unripe elderberries (not the same as a properly prepared supplement) can cause nausea and vomiting, so homemade or foraged elderberry preparations need to be fully cooked^[7].

Building a Realistic Routine, Not an Overhaul

None of this requires reinventing a household's routine. A long school year tends to be won with a short list of boring, repeatable habits rather than one dramatic change: a bedtime that holds even when homework runs late, handwashing before meals and after school, a water bottle that actually gets used, a few minutes of movement between long stretches at a desk — and, for families who want it, a daily elderberry habit as a small, low-effort addition on top of those fundamentals, not instead of them. Teachers benefit from the same short list; the wellness math doesn't really change once you're the adult running the classroom instead of sitting in it.

Frequently Asked Questions

Should I limit my child's screen time to a specific number of hours?

Current AAP guidance doesn't set a specific hour limit for school-age children, citing insufficient evidence that a fixed cutoff improves outcomes on its own. The more useful approach is checking whether screen use is displacing sleep, physical activity, or in-person time — and adjusting when it is^[3].

Does elderberry actually prevent colds, or just shorten them?

The evidence base is stronger for shortening the duration and severity of a cold once symptoms start than for preventing a cold from occurring at all. The largest single trial found no significant difference in how many people caught a cold, but a significant difference in how long and how severe those colds were^[4].

Is it safe to give elderberry to young kids every day during the school year?

Prepared, commercially made elderberry products (not raw or homemade preparations) are generally considered safe for daily use in the research reviewed here, and our lollipops are formulated for ages 4 and up. As with any supplement, check with your pediatrician first, especially for children with underlying health conditions or those taking medication.

What's the single most effective thing to reduce colds in a classroom?

Handwashing, by a wide margin. Community handwashing education has been shown to reduce respiratory illness by 16–21% and school absenteeism from GI illness by 29–57% — effect sizes well beyond what's been shown for any supplement^[2].

How does sleep actually connect to grades, not just feeling tired?

A 2025 systematic review found consistent links between better sleep and stronger cognitive performance, emotional regulation, and fewer behavioral problems in children 6–12 — though most underlying studies were correlational, so sleep is best understood as a strong contributing factor rather than the sole cause of academic performance^[1].

Sources

1. Félix A, Candeias A. Sleep as a Developmental Process: A Systematic Review of Cognitive, Emotional, and Behavioral Outcomes in Children Aged 6–12 Years. Clocks Sleep. 2025;7(4):66. doi:10.3390/clockssleep7040066
2. Centers for Disease Control and Prevention. Handwashing Facts. CDC Clean Hands. cdc.gov/clean-hands/data-research/facts-stats
3. American Academy of Pediatrics. Screen Time Guidelines. AAP Center of Excellence on Social Media and Youth Mental Health, Q&A Portal.
4. Tiralongo E, Wee SS, Lea RA. Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients. 2016;8(4):182. doi:10.3390/nu8040182
5. Hawkins J, Baker C, Cherry L, Dunne E. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complement Ther Med. 2019;42:361–365. doi:10.1016/j.ctim.2018.12.004
6. Wieland LS, Piechotta V, Feinberg T, et al. Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review. BMC Complement Med Ther. 2021;21(1):112. doi:10.1186/s12906-021-03283-5
7. National Center for Complementary and Integrative Health. Elderberry: Usefulness and Safety. nccih.nih.gov/health/elderberry

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 medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, immunocompromised, taking medication, caring for an infant, or considering a supplement for a child.