October 6, 2025, 9:16 am | Read time: 4 minutes
This time in “Highway to Health – Studies in Brief”: Ashwagandha has been used in herbal medicine for centuries. Now, researchers have systematically examined its actual effects on endurance, sleep, and stress resistance. Meanwhile, a large nutrition study shows that even subtle differences in the composition of a Mediterranean diet can leave measurable traces in the brain. Finally, a study with top athletes provides intriguing insights into how small changes in evening and morning routines can impact energy and performance—with surprising results.
The Potential Effects of Ashwagandha on Endurance, Sleep, and Stress Resistance
What Was Investigated? An analysis published in the journal “Muscles” summarized the results of eleven systematic reviews.1 The study examined how the intake of Ashwagandha (Withania somnifera) affects the body, well-being, and athletic performance in both healthy individuals and athletes. Researchers explored whether the plant improves endurance, aids sleep, alleviates stress, or stabilizes mood. They also considered possible influences on hormone levels and recovery.
Results: The summarized studies suggest that Ashwagandha may enhance physical performance, such as endurance, strength, and recovery. Many studies also showed reductions in stress and anxiety and improvements in sleep quality. Positive changes in testosterone levels and fertility were observed in men. These effects mainly occurred with daily intakes of at least 600 milligrams over a minimum of eight weeks. Reports of mild side effects (such as stomach discomfort or fatigue) were rare.
Significance: Ashwagandha is considered an “adaptogen,” a plant substance that can help the body better cope with stress and strain. While the current study results are promising, they do not yet provide conclusive evidence. The authors emphasize that many effects require further research. Therefore, the use of Ashwagandha should always be individually assessed and, if possible, medically supervised, especially in cases of pre-existing conditions or concurrent medication use.
How Ashwagandha Affects Aging
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Green Mediterranean Diet Measurably Slows Brain Aging
What Was Investigated? An international research team examined whether certain blood values are associated with brain aging and whether diet can influence this.2 They analyzed data from a larger nutrition study involving 294 overweight adults. Participants followed either general recommendations, the classic Mediterranean diet, or a particularly plant-rich “green” variant with plenty of green tea, walnuts, and Mankai (a type of duckweed, Wolffia globosa) for 18 months. The biological “brain age” was estimated using MRI images. Researchers calculated how much older or younger the brain appears compared to the actual age—this difference is referred to as the “Brain Age Gap.”
Results: Two specific proteins in the blood—Galectin-9 and Decorin—emerged as potential warning signs for accelerated brain aging. The higher their levels, the older the brain appeared compared to the biological age. Among participants on the green Mediterranean diet, Galectin-9 decreased by about 7 percent on average, while it remained unchanged in other groups. Decorin increased slightly in all groups, but least under the green diet.
Significance: The study published in “Clinical Nutrition” shows that a plant-rich diet can reduce biological markers of unfavorable brain aging in the blood. The green Mediterranean diet could protect the brain and slow aging processes in the head. However, since almost 90 percent of participants were men, it is unclear whether the results can be readily applied to women.
Morning Light, No Phone at Night! This Routine Boosts Performance and Mood in Professional Athletes
What Was Investigated? A study from Japan published in the “Journal of Strength and Conditioning” examined whether top athletes sleep better, perform better, and feel better when they avoid screens in the evening and expose themselves to bright light in the morning.3
Twelve of 25 athletes adhered to two simple rules for two weeks: no smartphones or tablets in the 30 minutes before sleep and a 20-minute light exposure immediately after waking, with brightness comparable to a strong daylight lamp (about 10,000 lux). The other group made no changes. Sleep, fatigue, mood, and athletic performance were measured.
Results: Athletes following the light-and-phone routine were more alert in the morning, felt more energetic, reacted faster, and jumped higher. Their jump power relative to ground contact time also improved. However, sleep itself did not change measurably.
Significance: After just two weeks, this simple adjustment positively impacted mood and performance metrics—without altering sleep. Whether people outside of professional sports could benefit was not studied, but it seems plausible. For professionals, this combination could be an effective addition to daily routines.
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