What Your Body Keeps

Sunday · 7:44 AM ET · Better Habits. Healthier Habitat.

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Every 7 days, we begin here with 4x4 box breathing.

Soften your jaw. Let your tongue relax from the roof of your mouth. Drop your shoulders. Take one round, or stay for a few until you feel grounded.

Inhale 4 sec · Hold 4 sec
Exhale 4 sec · Hold 4 sec

Welcome back to The Nest
September arrives this week, and with it comes the meteorological start of fall. The calendar still gives us a few more weeks of summer, but the light, routines, and pace of the days are already beginning to shift. A good week to notice what you want to carry into the next season.

A line to carry
“If you ever want to see the bright side of things, look in the mirror.”
(Submitted by Martin Iragorri)

In today’s digest, we’ll be discussing:

After staying awake for 30 hours, healthy young adults who either took a 90-minute nap or completed just 20 minutes of moderate-to-vigorous exercise performed about 22% better on a later memory test than people who did neither.

Interestingly, the two strategies appeared to help in different ways. Napping seemed to recharge the brain’s ability to take in new information, while exercise helped it work more efficiently with the resources it had left.

There is an important catch. Exercise did not erase the effects of sleep deprivation or replace actual sleep. It simply helped preserve memory when adequate rest was not an option.

The takeaway, sleep still comes first. But after a rough night, a short workout or a well-timed nap may help your brain make more of what it has left.

We experience far more in a day than our brains could possibly store. New research offers a clue for how the brain chooses what makes the cut.

In a sleep study, researchers tracked brain activity while people learned pairs of objects and words. Experiences accompanied by a particular pattern of theta-wave activity during learning were more likely to survive in memory after participants slept.

Those same learning signals were linked with brain activity during sleep that helps consolidate memories. In other words, the sleeping brain may not start from scratch. Experiences could be getting quietly “tagged” during the day for processing later that night.

Takeaway, sleep doesn’t simply shut the brain down. It may be the second half of the learning process, deciding what from today deserves a place in tomorrow.

Women with a history of gestational diabetes face elevated cardiometabolic risk after pregnancy, which makes the early postpartum period especially important. In a prospective study of 470 Japanese women with prior gestational diabetes, those whose babies received at least 80% breast milk had lower triglycerides, higher HDL cholesterol, and a healthier LDL-to-HDL ratio six to nine weeks after giving birth.

The associations persisted even after researchers accounted for insulin sensitivity and other variables. Because this was observational, it cannot prove breastfeeding caused the differences. Breastfeeding also isn’t possible or appropriate for every mother, and the findings should never be used to add pressure during an already demanding period.

The takeaway, pregnancy and postpartum health can reveal important clues about a woman’s future metabolic health. Support and follow-up matter long after delivery.

Where did the famous “10,000 steps a day” goal originally come from?

A. A World Health Organization guideline

B. A Japanese pedometer marketing campaign

C. A Harvard longevity study

D. U.S. military fitness standards

Answer below ↓

Gratitude is usually discussed as a way to feel better. New research suggests its effects may extend into behavior.

Researchers combined data from 24 studies involving nearly 7,000 people and found that people who reported greater gratitude also tended to engage more consistently in health-supporting behaviors such as physical activity, healthy eating, adequate sleep, and stress management.

The research doesn’t prove writing three things in a journal suddenly makes someone healthy. But gratitude may support self-regulation by shifting attention toward what is going well and making people more inclined to care for it. Sometimes the value of a mindset isn’t only how it makes you feel. It’s what it makes you do.

Takeaway, a gratitude practice doesn’t need to be profound. Notice something worth appreciating, then see whether that changes how you treat the rest of your day.

🥬 Some “healthy” foods may behave differently in an inflamed gut. Research suggests oxalate, found in foods such as spinach and almonds, could worsen intestinal inflammation in people with IBD under certain conditions, an important reminder that nutrition isn’t identical for every gut.

🧬 “Anti-aging” supplements may not be where the strongest signal is. A major new analysis of 51 intervention studies found that diet-and-exercise programs consistently shifted some epigenetic aging markers, while over-the-counter supplements generally did not. The bigger point is that scientists are getting better at measuring whether longevity interventions actually move biology.

💪 Training one side of your body can affect the other. A 2026 meta-analysis found that exercising the non-immobilized limb helped reduce strength loss in the opposite immobilized limb, an effect known as cross-education.

🥑 Keto had an impressive result, but under unusually controlled circumstances. In a small clinical trial where food was provided and weight loss was matched, the ketogenic group saw larger improvements in liver fat and glucose measures than Mediterranean and low-fat plant-forward groups. That's interesting metabolic science, not proof that everyone should go keto.

Dr. Angela Holliday-Bell is a board-certified physician and certified clinical sleep specialist who makes the science of better sleep feel refreshingly practical. Her content covers everything from insomnia and nighttime wake-ups to sleep routines, circadian rhythms, and the everyday habits that can quietly affect how well you rest.

Why follow: For evidence-based sleep advice that’s clear, useful, and easy to actually put into practice. She does a great job breaking down common sleep problems without overcomplicating them, while giving realistic tips you can use the same night.

Follow her here:

Instagram @thesleep_md ↗
Website The Solution is Sleep ↗

B. A Japanese pedometer marketing campaign

The number wasn’t originally discovered in a clinical trial. A Japanese company began selling a pedometer called the manpo-kei, or “10,000-step meter,” around 1965, shortly after the Tokyo Olympics. The catchy number stuck and eventually became a global fitness benchmark.

Try this week:
Use your step count as motivation, not a pass/fail test. Moving more than you normally do still counts.

Fruit
🍎 Apples · 🍐 Pears · 🍇 Grapes · 🫐 Blueberries · Blackberries · Raspberries
🍑 Peaches · 🍉 Watermelon · 🍈 Cantaloupe · Plums · Figs

Vegetables
🍅 Tomatoes · 🌽 Sweet corn · 🥒 Cucumbers · 🫑 Bell peppers · 🍆 Eggplant
🫛 Green beans · Zucchini · Summer squash · 🥦 Broccoli · Cauliflower · 🥬 Kale
🧅 Onions · 🥔 Potatoes · 🎃 Winter squash · 🌿 Fresh herbs

_{Seasonal availability may vary by region and growing conditions.}

If this brought a little calm or clarity to your Sunday morning, send it to someone who would appreciate it too.

If this week’s quote resonated with you, reply with one of your favorites.

We’ll choose one reader submission for next week’s line to carry.