Why Do We Need Sleep? Scientists Trace the Answer to Mitochondria

Sleep may serve as more than rest for the mind; it may also function as essential upkeep for the body’s energy systems. A new study from University of Oxford researchers, published in Nature, shows that the drive to sleep is caused by electrical stress building up in the tiny energy-producing structures of brain cells.

In certain sleep-regulating neurons studied in fruit flies, mitochondria that become overloaded begin leaking electrons. This leakage produces harmful byproducts called reactive oxygen species. The leak functions as a signal that forces the brain into sleep, allowing balance to be restored before cellular damage spreads further.

Despite decades of research, no one had identified a clear physical trigger. The findings show that the answer may lie in the very process that fuels our bodies: aerobic metabolism. In certain sleep-regulating neurons, mitochondria – the cell’s energy producers – leak electrons when there is an oversupply. When the leak becomes too large, these cells act like circuit breakers, tripping the system into sleep to prevent overload.”

The findings help explain well-known links between metabolism, sleep, and lifespan. Smaller animals, which consume more oxygen per gram of body weight, tend to sleep more and live shorter lives. Humans with mitochondrial diseases often experience debilitating fatigue even without exertion, now potentially explained by the same mechanism.

“This research answers one of biology’s big mysteries,”  “Why do we need sleep? The answer appears to be written into the very way our cells convert oxygen into energy.”

Reference

Mitochondrial origins of the pressure to sleep” by Raffaele Sarnataro, Cecilia D. Velasco, Nicholas Monaco, Anissa Kempf and Gero Miesenböck, 16 July 2025, Nature.

DOI: 10.1038/s41586-025-09261-y

Irregular sleep patterns, not just how long we sleep, may significantly raise the risk of numerous diseases

A major international study published in Health Data Science has revealed strong links between sleep patterns and the development of 172 different diseases. By examining objective sleep data from 88,461 adults in the UK Biobank, researchers uncovered compelling evidence that consistent sleep routines, including stable bedtimes and circadian rhythms, play a much larger role in long-term health than previously thought.

The research, led by scientists from Peking University and Army Medical University, tracked participants using actigraphy over an average of 6.8 years. The findings showed that poor sleep habits contributed to more than 20 percent of the risk for 92 diseases.

Reference: “Phenome-wide Analysis of Diseases in Relation to Objectively Measured Sleep Traits and Comparison with Subjective Sleep Traits in 88,461 Adults” by Yimeng Wang, Qiaorui Wen, Siwen Luo, Lijuan Tang, Siyan Zhan, Jia Cao, Shengfeng Wang and Qing Chen, 3 June 2025, Health Data Science.

DOI: 10.34133/hds.0161

Connect to Sleep Yoga for healthy Sleep

 

Daily Sleep Yoga session by Chronoprakriti Wellness launched on International Yoga day 2025

 

Caffeine induces age-dependent increases in brain complexity and criticality during sleep

Caffeine isn’t just in your morning coffee. It’s also in tea, chocolate, energy drinks, and many popular soft drinks, making it one of the most widely consumed psychoactive substances around the globe. Now, new research from the University of Montreal reveals how caffeine might be doing more than just keeping you awake. In a study published in Communications Biology, scientists discovered that caffeine can actually change how the brain recovers overnight, affecting both physical restoration and cognitive function.

They showed for the first time that caffeine increases the complexity of brain signals and enhances brain “criticality” during sleep. Interestingly, this was more pronounced in younger adults.

“Criticality describes a state of the brain that is balanced between order and chaos,” said Jerbi. “It’s like an orchestra: too quiet and nothing happens, too chaotic and there’s cacophony. Criticality is the happy medium where brain activity is both organized and flexible. In this state, the brain functions optimally: it can process information efficiently, adapt quickly, learn, and make decisions with agility.”

The researchers also discovered striking changes in the brain’s electrical rhythms during sleep: caffeine attenuated slower oscillations such as theta and alpha waves, generally associated with deep, restorative sleep, and stimulated beta wave activity, which is more common during wakefulness and mental engagement.

“These changes suggest that even during sleep, the brain remains in a more activated, less restorative state under the influence of caffeine, Young adults showed a greater response to caffeine, likely due to a higher density of adenosine receptors in their brains. Adenosine is a molecule that gradually accumulates in the brain throughout the day, causing a feeling of fatigue.

“Adenosine receptors naturally decrease with age, reducing caffeine’s ability to block them and improve brain complexity, which may partly explain the reduced effect of caffeine observed in middle-aged participants,” Carrier said.

And these age-related differences suggest that younger brains may be more susceptible to the stimulant effects of caffeine. Given caffeine’s widespread use around the world, especially as a daily remedy for fatigue, the researchers stress the importance of understanding its complex effects on brain activity across different age groups and health conditions.

Ref:

Thölke, P., Arcand-Lavigne, M., Lajnef, T. et al. Caffeine induces age-dependent increases in brain complexity and criticality during sleep. Commun Biol 8, 685 (2025). https://doi.org/10.1038/s42003-025-08090-z

Should Children Be Taking Melatonin Supplements?

Melatonin is produced in the pineal gland to induce sleep. However, melatonin is also naturally produced throughout the body, including in the gastrointestinal tract, reproductive tissues, skin, and liver, to name a few, and is used in the body for more than regulating our circadian rhythm or sleep/wake cycle.

The pineal gland is the primary source of melatonin production for our sleep/wake cycle and responds to environmental cues, namely the lack of light or darkness, to increase production and prepare us for sleep. Less commonly known is that children and teens produce many times more melatonin than adults, up to 5 times as much in their teens compared to a 50-year-old.  Making it an unlikely cause for sleep issues in younger people and less likely that kids need to take melatonin as a supplement.

If any person, especially a child, uses a product with more melatonin than they think they are taking, we run the risk of misuse or overdose. Additionally, melatonin is available in gummies and chewable forms that can make it more appealing to children, further increasing the risk of misuse or overdose. While melatonin appears safe for most children, at present, clear guidelines on the dose, timing, or length of use of melatonin have not been established. In agreement with the recommendations made by the American Academy of Sleep Medicine (AASM), it is recommended to discuss melatonin supplementation with their healthcare professionals before giving it to children. Conversely, there is a consensus that supporting better sleep habits and sleep hygiene is an excellent first-line approach that should be considered for most children, teens, and their families.

There are some cases where melatonin may benefit younger people though more research is needed. Data is emerging around some genetic variants in which some people may not produce melatonin at the same levels as others. In particular, this may be the case for some who live with ADHD or are on the autism spectrum and often have delayed sleep phases and difficulty sleeping. Interestingly, the use of low doses of melatonin (0.2 - 0.5 mg) is promising, supporting a growing trend in melatonin research that more is not always better.

While it may not be appropriate for all kids, when melatonin is needed, choosing a physiological-dose, plant-based phytomelatonin, may provide all the benefits for the sleep/wake cycle and several other uses for immune and cellular health support.

https://www.phytomelatonin.org/in-the-news-children-and-melatonin

A ‘Reset’ Button For Stress/Anxiety & Proven Way To Activate Your Body’s Natural ‘Relaxation Response

When you breathe in you're activating your body's sympathetic response (also known as 'fight or flight'), increasing heart rate & boosting energy, alertness, focus & concentration. And when you breathe out, you're doing the exact opposite... down-regulating your nervous system & activating your para sympathetic response (also known as the 'rest-and-digest' response; or your body’s natural 'relaxation response').

Here's how to practice the full technique

1.Be comfortable. Sit or lie down in a relaxed position

(you can do this technique in any position)

2. It's recommended that you start this (& many other techniques) by first emptying your lungs(e.g. with a whooshing exhale)

3. Start by inhaling quietly through your nose for 4 seconds.

4. Hold your breath for 7 seconds

(don't tense up here relax your muscles during this pause & enjoy the stillness)

5.Then exhale through your mouth for 8 seconds making a whooshing sound as you do.

6. Repeating this for 4-8 cycles is a great starting point.

www.potenciaeducation.com