How Your Body Makes Energy: Your Energy Battery Explained

Years ago, in my late 30s, our little family of five walked through something unimaginably difficult. It was the most emotionally challenging season I had ever experienced.

I woke up exhausted every single day. For months, my body was stuck in a loop of cortisol and adrenaline, always on high alert. My sleep, my mood, my hunger, my cravings, all of my biofeedback was out of whack, and my energy was the lowest it had ever been.

Knowing what I know now, I can see it so clearly. That was not a season to push. It was a season to nourish.

This week I asked you to rate your energy over the past few weeks. If your number was lower than you would like, I want you to know you are not alone, and you are not failing. Tired, flat, running on caffeine, crashing in the afternoon. “I hear it from so many women in midlife, and it is why I want to start this month by looking at how your body makes energy.”

We tend to think of energy as a feeling, or even a personality trait. But energy is not a mystery. It is biology. Your body makes it and spends it every second of every day. When we understand how that works, we can stop pushing and start nourishing.

So let’s start at the very beginning: what energy actually is, how your body makes it, and where it all goes.

A little bit of the science, made simple

Every single thing your body does runs on one tiny molecule called ATP (adenosine triphosphate). Every heartbeat, every breath, every thought, every step, and every hug runs on ATP. You can think of it as your body’s energy currency.

Here is the fascinating part. Your body only holds a small amount of ATP at any moment, so it has to make it constantly and recycle it over and over again. In fact, your body turns over roughly its own weight in ATP every single day. That is how much energy it takes just to keep you alive and moving.

Most of that ATP is made inside tiny structures in your cells called mitochondria. You may remember them from high school biology as the “powerhouse of the cell.” They take the food you eat and the oxygen you breathe and turn them into usable energy. Your muscles, heart, and brain are packed with them, because those are the parts of you that need the most energy.

Think of your energy like a battery

I find it helpful to picture your energy like the battery in your phone. There are four things that determine how well that battery works for you.

1. The charge: food and oxygen. Your mitochondria make ATP from the food you eat. Carbohydrates are your quickest fuel, healthy fats are your long-lasting fuel, and protein is mostly saved for building and repairing, though your body can use it for fuel too. Oxygen is what lets your mitochondria turn that fuel into energy efficiently.
2. The charging cord: vitamins and minerals. As we learned in Module Two, micronutrients do not give you calories, but your body cannot make energy without them. B vitamins, iron, and magnesium all play key roles in turning food into ATP. Iron is especially important because it carries oxygen to your cells. Think of them as the charging cord. You can have the outlet right there, but with a frayed cord, your phone barely charges. When any of these nutrients run low, your battery struggles to charge no matter how well you eat.
3. A steady charge: blood sugar balance. When blood sugar spikes and crashes, your energy does too. Meals built with protein, fiber, healthy fats, and smart carbs, like the NOURISH Plate, give your body a slow, steady stream of fuel instead of a quick burst followed by a slump.
4. The battery size: your mitochondria. This is the part most women have never heard about. The number and health of your mitochondria decide how much energy your body can produce. They tend to decline with inactivity and age. But here is the good news: they respond to movement. In one small but fascinating study, older adults who did interval training for 12 weeks increased their mitochondrial capacity by 69%. Movement literally builds you a bigger battery.

And then there is the charging station: sleep. Sleep is when your body repairs, restores, and resets the hormones that regulate your energy and hunger. No amount of good food can fully make up for a body that is not getting the rest it needs.

Where your energy goes

Here is something that surprises most women: the majority of your energy is not spent on exercise. It is spent simply keeping you alive. Scientists break your daily energy use into three parts:

• Keeping you alive (about 60 to 70%). Your resting metabolism powers your heart, lungs, brain, liver, kidneys, and muscles, even while you sleep. This is by far your biggest energy expense.
• Digesting your food (about 10%). It takes energy to break down, absorb, and use what you eat. Protein takes the most energy to digest, which is one more reason it is such a good anchor for your meals.
• Moving your body (the rest). This includes your workouts, but also everything else: walking to the mailbox, cleaning the kitchen, gardening, even fidgeting. For most of us, this everyday movement adds up to more than our actual exercise.

And one organ deserves its own mention: your brain. It makes up only about 2% of your body weight, yet it uses about 20% of your body’s energy. Your brain is always on, always working, always spending.

Physical, mental, emotional, spiritual: is it all the same energy?

We often say we feel physically tired, mentally drained, emotionally exhausted, or spiritually empty. So does each kind of tiredness pull from a different tank? Here is what the science tells us.

Physical energy is the most straightforward. When your muscles work, they spend ATP, and your body makes more to keep up.

Mental energy is where it gets interesting. Your brain already uses a lot of energy all day long, but hard thinking adds surprisingly little. Researchers have found that a demanding mental task raises brain energy use by less than 5% above its normal level. So why does a long day of decisions leave us so worn out? Mental fatigue is very real, but scientists believe it has more to do with brain chemistry, focus, and motivation than with burning extra fuel. This is one of the areas where the science is still unfolding.

Emotional energy is tied closely to your stress response. When you feel stressed, your body releases hormones like cortisol and adrenaline that pull stored fuel into your bloodstream so you are ready to act. That is a gift in a short burst. But when stress stays switched on day after day, like it did for me in that hard season, it keeps your body on high alert, disrupts your sleep, and can leave you feeling wired and tired at the same time.

Spiritual energy is not something science can measure in calories, but I have never doubted it is real. From the very beginning, God built rest into the rhythm of creation, and Jesus offers an invitation I return to again and again: “Come to me, all you who are weary and burdened, and I will give you rest.” (Matthew 11:28)

Research is beginning to catch up with what Scripture has always told us. In one study of nearly 7,000 adults over 50, those with the strongest sense of purpose in life were less than half as likely to die over the following years as those with the weakest. Other research has linked a strong sense of purpose with lower stress hormones and less inflammation.

So here is where the science lands: it is all one battery. Your thoughts, emotions, and spirit do not each have their own separate tank. They all draw from, and pour into, the same body. That is exactly why caring for yourself mind, body, and spirit matters so much.

What drains your battery

When energy is low, it is usually not one thing. It is a few small drains adding up. Here are the most common ones I see in women in midlife:

• Poor or short sleep. Your charging station is not getting enough time.
• Blood sugar swings. Skipping meals, low-protein breakfasts, and sugary snacks lead to spikes and crashes.
• Under-eating. When your body does not get enough fuel, it conserves energy, and you feel it.
• Nutrient gaps. Low iron (especially with heavy periods in perimenopause), low B12, and low vitamin D are common, and all are worth checking when you are tired.
• Too little movement. Without movement, your battery slowly shrinks.
• Chronic stress. A body stuck on high alert burns through its reserves.
• Hormone shifts. The changes of perimenopause and menopause, as well as thyroid issues, can all affect your energy.

If you have been tired for a long time despite doing a lot of things right, please talk with your doctor. Simple blood work can check your iron, B12, vitamin D, and thyroid. Sometimes the answer is hiding in plain sight.

Where I land on this

Low energy is not a character flaw, and it is not just part of getting older. It is your body telling you something. When we learn to listen, we can respond with care instead of pushing harder or reaching for another cup of coffee.

I believe God gave us these bodies, and the energy to live in them, for a purpose. Not to drag ourselves through our days, but to love our people well, serve with joy, and do the good work He has prepared for us. Caring for our energy is part of that stewardship.

This month, we are going to learn how to charge our batteries well, so we have all the energy we need, plus some, to live out our purpose and passion with great joy.

“The joy of the Lord is your strength.” Nehemiah 8:10

Your next step

If you are in NOURISH, pull out the energy score you wrote down this week. Read through the list of drains above and ask yourself: which two or three might be quietly pulling my battery down? Hold on to your answer. We will build on it together this month.

If you are new here, take a moment to rate your energy over the past few weeks on a scale of 1 to 10. Then look at the list of drains and notice which ones sound familiar. That is your starting point.

Ready to Go Deeper?

Understanding how your energy works is the first step. Learning how to support it in a way that fits your real life is the next one.

NOURISH members, we will keep unpacking energy together all month long. Bring your questions as we go. That is what we are here for.

If you are not part of NOURISH yet, this is exactly the kind of work we do together every single week. We are a faith-based integrative health coaching community for women in midlife. We talk about hormones, nutrition, movement, sleep, stress, and the faith that holds it all together, in simple practical language that actually fits real life.

Learn more and join us here!

Health and blessings,
Ann

About Ann Hackman

Ann Hackman is a certified integrative health coach and founder of NOURISH, a faith-based integrative health coaching community for women in midlife. She helps women understand their bodies, balance their hormones, and restore their health through the lens of mind, body, and spirit.

I am a certified health coach, not a physician. Please work with your doctor for personalized medical guidance.