Introduction
For years, I thought I had sleep figured out. I was running on four to five hours a night, waking at 3 or 4 AM with my brain racing through my to-do list, and I would just get up and start my day. I told myself I was fine.
Looking back, I was not fine. I was running on cortisol and stress hormones. My body was in survival mode.
These days, I am doing things differently. I go to bed around 9 PM and no later than 10 PM, and I aim for a solid seven-plus hours. My Garmin Fenix tells me my body battery rarely gets above 65-70% when I wake up. My goal is 100%, because that is what truly restorative sleep looks like.
What changed my thinking was discovering why we actually need sleep in the first place. Scientists have recently uncovered a mechanism that makes practical sense.
Why Your Brain Forces Sleep
For decades, scientists debated why we need sleep. Memory consolidation, hormone balance, and immune function are all part of the picture, but none of those alone explained why every creature with a brain must sleep.
Then researchers at Oxford studied fruit flies and identified a core mechanism tied to cellular energy production.
Your mitochondria are tiny power plants inside every cell. They produce energy around the clock, but the process is not perfectly clean. Mitochondria leak electrons, and when those electrons react with oxygen, they form reactive oxygen species (ROS).
Think of ROS like sparks from a grinder. A few sparks are manageable. Too many sparks create a fire risk.
Your brain pushes you into sleep when those toxic sparks build up to dangerous levels. In that sense, sleep acts like an emergency shutdown that protects neurons.
The breakthrough came when researchers modified fruit-fly mitochondria to reduce electron leakage. Those flies needed less sleep. When leakage increased, flies slept longer and deeper.
This is not just a fruit-fly phenomenon. The same broad mechanisms exist in humans.
The amount of electron leakage, and therefore part of your sleep pressure, is heavily influenced by which fuel your body is burning.
When I was living on four to five hours of sleep, I thought I was being efficient. In reality, I was stressed. My body was pumping out cortisol to keep me moving, and when I woke at 3 or 4 AM, my mind took off into planning and problem-solving.
I was not optimizing my mitochondria. I was running on fumes.
Now I understand more of what is happening at the cellular level, and I am making changes. I have not mastered this. I am still learning and improving, but understanding the mechanism changed my entire approach.
The Fat-Burning Problem
During those high-stress, low-sleep years, I missed a key point: when your body burns a lot of fat under chronic stress, it can overload your cellular machinery in ways carbohydrates do not.
Bioenergetic researcher Georgi Dinkov explains this clearly. Excessive fat burning, especially during ongoing stress, depletes a molecule called FAD. FAD is made from vitamin B2 and is essential for proper mitochondrial energy processing.
When FAD runs low, electrons back up in the energy chain. I think of it like a traffic jam. Electrons cannot move forward efficiently, so more of them spill into side reactions that increase ROS.
Your body's response is to force sleep, shut things down, and clean up the damage.
I used to see this after long bike rides 10 to 15 years ago. I once did a 100-mile ride in Savannah. Even on shorter rides of several hours, I would come home wiped out, need a nap, and still sleep heavily that night.
At the time, I thought I was just training hard. Now I see that I was flooding my system with fatty acids and increasing electron leakage. My body needed extra sleep to recover.
The Serotonin Connection
There is another piece to this puzzle: serotonin.
Most people think of serotonin as a happiness neurotransmitter. It also contributes to drowsiness.
When you burn a lot of fat, fatty acids rise in the bloodstream. Those fatty acids displace tryptophan from its carrier protein. More free tryptophan enters the brain, where it converts to serotonin.
Higher serotonin can increase fatigue and sleep pressure.
This helps explain why you can feel exhausted after a stressful day even without intense physical activity. Looking back, my 3 AM wake-ups with racing thoughts were likely cortisol trying to keep me functional while my mitochondria were overloaded.
What I Am Changing Now
Once I understood this, I started changing my routine. I am not perfect, but these are the practices I am using now.
1. Going to bed earlier and aiming for more sleep
I used to stay up past 11 PM and accept whatever sleep I got. Now I aim to be in bed near 9 PM and no later than 10 PM. I target at least seven hours, and in practice I do best when I get closer to eight.
I am currently in Argentina, where dinner often starts after 9 PM, so this is not always easy. But the target is clear.
My Garmin body battery score is humbling. I still wake up around 65-70% most days. My goal is to consistently reach 100%.
2. Eating more carbohydrates
This surprised me. In my case, carbohydrates are often a cleaner fuel for mitochondria than heavy fat oxidation. They can reduce electron leakage when used appropriately.
I focus on healthy carbohydrates from fruit and other whole-food sources to support steady energy and reduce toxic byproduct buildup.
3. Choosing moderate exercise over extreme endurance
I have not done multi-hour endurance rides in over a decade. These days, my bike sessions are usually about an hour, often in zones 2 and 3.
I also use the rowing machine several times per week for 30 to 45 minutes, generally in high zone 2 to low zone 3.
Compared with my old endurance sessions, the difference is clear. I now finish workouts feeling energized instead of depleted.
4. Using aspirin strategically
I use low-dose aspirin at times (about 100-150 mg, around four or five days per week) because it may help lower circulating free fatty acids and serotonin load.
I am not recommending this for everyone. You need to review this with your physician, because aspirin is not appropriate for every person.
5. Timing carbohydrates around activity
After morning training, I make sure to have fruit or another quick carbohydrate source. That helps prevent a hard shift into heavy fat-burning mode when my cells are trying to recover.
6. Focusing on mitochondrial efficiency
The goal is more than sleeping longer. I want mitochondria that run cleanly so the sleep I get is genuinely restorative.
My 65-70% body battery score tells me I still have work to do, but I am moving in the right direction.
The Seed Oil Problem
Another major factor for me is seed oils.
Seed oils such as soybean, canola, corn, sunflower, and safflower are high in linoleic acid. In the high amounts common in modern processed food, linoleic acid becomes incorporated into mitochondrial structures, including cardiolipin in the inner mitochondrial membrane.
The issue is that linoleic acid is unstable and oxidizes easily. That process can generate toxic metabolites such as 4-HNE (4-hydroxynonenal), damage mitochondrial function, and worsen electron leakage.
Linoleic acid also has a long half-life in tissue, often described in years, which means full clearance is slow.
I started reducing seed oils about three years ago. I cook with butter, beef tallow, or coconut oil, and I use high-quality olive oil in appropriate ways. I read labels carefully and avoid most fried foods.
This shift has helped my energy more than almost anything else I have changed, though I know full recovery from long-term accumulation takes time.
The Bottom Line
Sleep is not wasted time. It is a repair protocol.
How much sleep you need is influenced by how cleanly your mitochondria are running, how much oxidative stress you are creating, and how much recovery work your system has to perform overnight.
I am not claiming I have solved all of this. My Garmin still reminds me that I have room to improve.
But now I understand the mechanism, and that changes how I train, eat, and recover.
When mitochondria run efficiently, cells leak fewer electrons, produce fewer harmful byproducts, and recover better. Better sleep quality follows.
I am 75 years old, and I am still learning, still experimenting, and still adjusting based on what the data and my body are telling me.
The research points to practical actions: support mitochondrial function with cleaner fuel choices, avoid chronic overreaching in exercise, reduce linoleic-acid-heavy seed oils, and improve stress and sleep routines.
You may not hit a perfect body battery score overnight. I have not either. But better energy, clearer cognition, and deeper recovery are realistic goals.
For me, this is an active process, and I believe it is one worth pursuing.