In 2025, Andrea Bazzani and Ugo Faraguna from Italian universities wrote an editorial reviewing how eating and sleeping are linked. They looked at past studies showing poor sleep changes what we crave, like more sweets and high-calorie foods, due to hormone shifts like less leptin (fullness signal) and more ghrelin (hunger signal). This can lead to overeating and weight gain.

In 2023, Daniel P. Windred and a team studied sleep patterns in thousands of adults across multiple cohorts, finding that sleeping in on weekends, called social jetlag, disrupts your body’s internal clock. Each hour of jetlag raises heart disease risk by 11% and worsens mood, obesity, and unhealthy habits like smoking or poor diet. A 2019 study by C.M. Depner showed that catching up on sleep after five short nights still caused 10-15% worse insulin sensitivity and higher calorie intake, leading to weight gain risks.

In 2022, a team reviewed six studies with 295 adults to see how exercise helps insomnia. They found that regular workouts, like walking or yoga, improved sleep quality and cut insomnia severity by 20-30%, making it easier to fall and stay asleep.

In 2015, J. R. Dalenberg and a team from Denmark conducted two field experiments with 30 students in dorm rooms. They tested ventilation by opening windows (low CO2: 660 ppm) or using a fan (low CO2: 835 ppm) vs. no ventilation (high CO2: 2,585 ppm or 2,395 ppm) for 1 week each. Sleep was tracked with wrist actigraphs, and next-day alertness via questionnaires and cognitive tests.

In 2012, Makoto Bannai and team from Ajinomoto Co., Inc. tested 7 healthy men (average age 40.6) who slept 25% less than usual for three nights. They took 3 grams of glycine or a fake pill before bed, then rated sleepiness and fatigue using scales and questionnaires, and did computer tests for alertness and focus.

In 2023, Valentina Paz and team from University College London and Uruguay studied 35,080 adults from the UK Biobank. Using brain scans and self-reported nap habits, they explored links between napping frequency and brain volume, adjusting for age, sex, and lifestyle factors.

In 2025, Yimeng Wang and team from Peking University studied 88,461 UK Biobank adults who wore wrist trackers for a week, followed for 6.8 years. They checked six sleep traits, like consistent bedtimes and steady rhythms, against 172 diseases, adjusting for age, diet, and lifestyle.

A 2025 cohort study of 291 Canadian youths (ages 10–18) found that sleeping more than 9.9 hours per night in the first two weeks after a concussion was linked to more severe symptoms and a higher risk of lingering effects at four weeks.

A 2025 study cited in Muscle & Fitness by the National Library of Medicine found that drinking green tea daily for 20 years raised testosterone levels by 30% in men compared to non-drinkers.

A 2023 study by Paz V et al. linked regular daytime napping to larger brain volume. Analyzing 378,932 people aged 40-69 from the UK Biobank, researchers used Mendelian randomization to find that those genetically prone to napping had brains 15.8 cm³ larger, equivalent to 2.6-6.5 years less brain aging.

Ashwagandha, a powerful herb used in traditional medicine, has been shown in a 2025 review to help reduce stress, fatigue, anxiety, and depressive symptoms. It also supports better sleep and sharper mental focus, boosting overall feelings of well-being—even for older adults aged 60–85.

A 2025 randomized, double-blind, placebo-controlled trial published in Nutrients found that supplementing with 100 mg each of vitamin B1 (thiamine) and B2 (riboflavin) daily for four weeks significantly reduced perceived stress and improved sleep quality in young adults.

A 2025 study in Nutrients found that adults who slept longer and had better sleep quality also had stronger handgrip strength—but only when they consumed more protein and followed a higher-quality diet.

A 2025 study from Université de Montréal, published in Communications Biology, revealed that consuming caffeine—even just a few hours before bedtime—can increase high-frequency brain activity during sleep. This is especially true for young adults, whose brains are more sensitive to stimulants.

A 2025 study from Uppsala University found that even short-term sleep deprivation raises inflammation-related proteins linked to cardiovascular disease, even in healthy young adults.