We all know what having energy feels like — you’re awake, alert, and in high spirits. You’re motivated to smash through your to-do list, tackle a tough workout, or spend quality time with your friends and family.
And we all know how it feels to have no energy — we’re sluggish, slow, and even the tiniest of tasks can feel impossible to complete.
But where exactly does this elusive energy come from, and how do we get more of it? In this blog post, we’ll dive into what exactly gives you energy, so you can understand where the thing we all want actually comes from.
In real terms, you might think of energy as the absence of tiredness or perhaps that buzz you get after consuming caffeine. But have you ever thought about what it really is and where it comes from?
Biologically speaking, our bodies get energy from the food we eat. This energy comes from three classes of fuel: carbohydrates, lipids, and proteins. Your body breaks down the food you eat and absorbs it into your bloodstream, allowing your cells to metabolize these nutrients. So “energy” as we think of it is actually our body metabolizing food and converting it into fuel it can use to function.
Here’s a quick biology lesson to help you understand where energy comes from:
Mitochondria are key to energy production and they’re often called the powerhouse of the cell. They’re present in almost every type of cell in our bodies, and they transform the chemical energy we get from food into an energy form a cell can actually use.
They convert glucose and oxygen into adenosine triphosphate (ATP), the main fuel source for cells, through reactions known as the citric acid cycle or the Krebs cycle.
This cycle produces NADH, a chemical used by enzymes in the mitochondria to make ATP. ATP molecules store energy in chemical bonds. When the bonds are broken, the energy can be used by the cell.
Your circadian rhythm is your body’s biological clock. It runs on a roughly 24-hour cycle and dictates things like your sleep-wake cycle, body temperature, hunger levels, and hormone production.
You have one master clock in your brain, called the suprachiasmatic nucleus (SCN), which is found in the hypothalamus region. The SCN is primarily controlled by the light-dark cycle of the outside world, but it’s not the only body clock you have.
Almost every tissue and organ group in your body is running on its own circadian rhythm. These are called peripheral clocks, and they’re in almost constant communication with the SCN.
Your circadian rhythm controls not only how much energy you make, but when you make it. When it’s working smoothly, you’ll feel energy at the right times. When it’s not, you might be wired at night and sluggish during the day, or simply not producing the amount of energy you could be as the processes related to energy production are thrown out of whack inside your body.
The RISE app predicts your circadian rhythm each day, based on things like how long you slept for the night before. It shows you a visual representation of this, so you can see when your energy levels naturally fluctuate throughout the day.
Mitochondria divide (called fission) and bond (called fusion) together, creating a network. This process is called the mitochondrial fission-fusion cycle, and this cycle follows the circadian rhythm.
So, your circadian rhythm helps to determine how much energy the mitochondria supply and when they supply it. But if you’re living out of sync with your circadian rhythm (perhaps from late nights and irregular sleep and meal times), the mitochondrial rhythm gets thrown off and they don’t make as much energy in the cells.
Your mitochondria process different fuels in different ways. Glucose from carbs, amino acids from proteins, and fatty acids or ketone bodies from fats can all be used to make ATP. This is called metabolic flexibility.
When metabolic flexibility is working as it should, mitochondria can keep providing your cells with energy, even when one fuel source isn’t available. Plus, they can use excess fuel stored in fat cells when there is no new food, such as when you’re sleeping.
When metabolic flexibility is disrupted, however, your body simply can’t produce energy as efficiently. Plus, you may develop type 2 diabetes, cancer, or metabolic syndrome, which includes high blood pressure, diabetes, and obesity.
How exactly does metabolic flexibility get disrupted? You can blame our modern lifestyles for that. Eating processed calorie-dense foods, eating too often throughout the day, not getting enough sleep, and doing little physical activity all impact our mitochondria’s ability to adapt to different fuel sources.
Plus, as your mitochondria respond to your circadian rhythm, disruptions to your body clock (through irregular sleep cycles or eating and sleeping at odd times) can lead to metabolic inflexibility.
So, to make sure your body’s energy production is working at its best, focus on the inverse. Eat a balanced diet, exercise, get enough sleep and sync up with your circadian rhythm. More on how to do that soon.
Looking for a quick pick-me-up? We’ve covered 20 science-backed ways to wake yourself up here. The advice includes taking a cold shower, listening to your favorite music, and getting your heart rate up with exercise.
These methods can give you a jolt of energy during a sluggish afternoon. But for sustained energy improvements, you need to focus on sleep debt and circadian alignment.
Your sleep need is the individual amount of sleep your body needs each night. It’s determined by genetics, just like height and eye color, and it’s not eight hours for everyone.
The average sleep need is 8 hours 10 minutes, plus or minus 44 minutes or so, but 13.5% of us may need 9 hours or more sleep a night.
To find out your unique sleep need, turn to the RISE app. RISE uses your phone use behavior and proprietary sleep-science-based models to work out your sleep need and give you a number to start aiming for each night.
RISE users on iOS 1.202 and above can click here to view their sleep need.
Why is meeting your sleep need so important?
Every moment you're awake, a natural compound called adenosine builds up in your brain, making you feel drowsier throughout the day as the level increases (also known as sleep pressure). When it reaches a certain level, you’ll get the urge to sleep.
When you do sleep, adenosine is purged from your system. The balance is reset and the cycle begins again when you wake up. This is all part of the homeostatic process — or the balance between sleep and wakefulness.
However, when you don’t get enough sleep, your body doesn’t have enough time to purge all the adenosine in your brain, so you wake up with it still in your system, making you feel groggier than usual. Caffeine temporarily blocks adenosine receptors in your brain, but this eventually wears off, leaving you with that familiar tired feeling again.
It’s more than just adenosine making you tired, though. Getting enough sleep is crucial to keeping your body’s energy production working smoothly.
In fact, research suggests even just one week of sleep deprivation can result in significant changes to your metabolic function as it messes with the hormones involved in regulating glucose regulation and causes inflammation.
In an ideal world, we’d all meet our sleep need each and every night. But with late-night socializing, early morning meetings, and those nights where you just can’t seem to drift off, getting enough sleep doesn’t always happen.
That’s where sleep debt comes in. Sleep debt is the running total of how much sleep you owe your body compared to your sleep need. It’s measured over the last 14 nights. The more sleep debt you have, the worse you’ll feel and the worse your body will be performing.
Your energy levels take a hit, but so does your concentration, mood, and memory. And sleep deprivation is linked to everything from diabetes to anxiety to heart disease, and it even makes weight loss harder.
There is a bit of wiggle room here, though. We recommend keeping sleep debt below five hours to optimize your energy levels and avoid these negative effects. RISE can work out how much sleep debt you’re carrying and keep track of it as you pay it back. You can learn more about how to pay back sleep debt here.
By finding out your sleep need, aiming to get it each night, and keeping sleep debt as low as you can, you’ll ensure your body’s energy production processes are working smoothly.
Your circadian rhythm controls so much in your body: your sleep-wake cycle, your hunger levels, and how much and when your cells produce energy. So it’s worth paying attention to it and working to stay in alignment with it each day. This means matching your social clock to your biological clock.
Circadian misalignment not only messes up your energy production capabilities, leading to daytime fatigue, it also increases your risk of obesity, diabetes, mood disorders, heart disease, and cancer.
You can use RISE to see a visual representation of your circadian rhythm each day. It goes like this:
When your sleep debt is low, these energy peaks will be higher and those dips will be shallower, improving how you feel throughout the day.
Stay in alignment with your circadian rhythm by:
We cover more ways you can stay in alignment with your circadian rhythm to get more energy here.
When we say we want to have more energy, most of us aren’t thinking about our mitochondria and how much ATP they’re creating. We simply want more vigor in life, more motivation to do things, and less brain fog.
By lowering sleep debt and staying in circadian alignment, you’ll experience improvements in many areas of life. After all, we don’t just want energy for energy’s sake — we want it to improve our lives in some way, either by performing better or by enjoying it more.
Low sleep debt and circadian alignment can:
Food is obviously a huge factor in how much energy you feel each day. Eat a healthy diet rich in whole foods, antioxidants, healthy fats, and sources of protein, and you’ll get the health benefits. Consume nothing but junk food and soda and you’ll be left feeling sluggish.
Here’s a quick overview of the foods to eat and avoid for maximum energy levels.
There are plenty of foods that give you a boost of energy and plenty that positively affect your sleep.
A 2022 paper stated:
“In general, diets rich in fiber, fruits, vegetables, and anti-inflammatory nutrients and lower in saturated fat (eg, Mediterranean diet) were associated with better sleep quality.”
Here are the energy-boosting foods to add to your diet:
Biologically speaking, all foods are a source of energy. But some foods have a high glycemic index, meaning they spike your blood sugar levels, giving you a quick buzz, followed by a crash. These include white rice, sugary foods, and potatoes.
It’s not all about food, watch out for these drinks, too:
The RISE app can tell you the best time to have your final cup of coffee and alcoholic drink each day to stop them affecting your sleep.
RISE users on iOS 1.202 and above can click here to set up their Limit Caffeine habit and here for the Avoid Late Alcohol habit.
What you eat is hugely important for energy, but when you eat makes a difference, too. Eating is a zeitgeber (German and science-speak for time-giver). This is an external cue that syncs your circadian rhythm to the outside world.
If you eat at odd times — like at night or vastly different times each day — you’ll confuse your body clock, leading to circadian misalignment. And circadian misalignment, as we’ve said, leads to low energy during the day and a whole host of health issues.
What’s more, eating too close to bedtime can either keep you up or wake you up in the night. You may experience digestive issues like indigestion, heartburn, and acid reflux. This makes it harder to meet your sleep need, which, of course, leads to daytime fatigue.
Research shows eating at night or in the time leading up to bedtime is negatively associated with sleep quality variables. High-caloric food intake 30 to 60 minutes before bed resulted in greater sleep latency, or the amount of time it takes to fall asleep.
Even if eating too close to bedtime doesn’t wake you up, it may be impacting the sleep you get. When you sleep, your brain clears out waste products. If your body is busy digesting food while asleep, blood flow may be diverted away from the brain to the gut, leaving the brain with less resources to clear out the junk overnight.
To stop all this from sabotaging your energy levels, here’s what to do:
You can learn more about sleeping after eating here.
Heads-up: You can’t out-eat bad sleep. Even if you’re eating the best foods for energy and your diet is packed with superfoods, if you’re not meeting your sleep need, you’ll feel tired each day. Make adjustments to your diet, of course, but don’t neglect sleep in your journey to gaining more energy.
We could talk forever about the science of energy production. But what most of us really want to know is how to get more energy to enjoy each day. The RISE app can help.
Use the app to work out your individual sleep need and how much sleep debt you have, as well as see a visual representation of your circadian rhythm each day.
Armed with this information, you can make sure you’re getting enough sleep each night (RISE will guide you through 20+ sleep hygiene habits to make this easier), pay down your sleep debt, and sync your sleep, meals, and daily tasks to your circadian rhythm. Head here for a deeper dive on how to track and mange your energy with the RISE app.
It sounds like a lot, but small lifestyle tweaks can result in huge energy gains, meaning everything in life — from work to family life to your hobbies — will feel easier and more enjoyable.
To get more energy fast, you can get natural light, drink coffee, exercise, or take a 10-minute nap.
The food we eat gives us energy. It’s broken down in the gut, absorbed into the bloodstream, and turned into fuel cells can use throughout your body. But many things can get in the way of this energy production process, including not getting enough sleep and being out of sync with your circadian rhythm.
Things that give you energy include low sleep debt, being in sync with your circadian rhythm, eating the right foods, eating at the right times, maintaining excellent sleep hygiene (to help you get the right amount and the best kind of sleep each night).
You might have no energy if you've got high sleep debt or you’re living out of sync with your circadian rhythm. A medical condition or nutritional deficiency can also be to blame.
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