Energy is life. Our bodies are an intricately complex system built for the essential work of generating and dispersing energy. And our mitochondria are these little energy-making machines inside almost every single one of our cells. But believe it or not, we’re the ones in control of how much energy they make. Our lifestyle habits have a huge effect on how much energy our cells create. The more active we are, the more energy our cells require, which then causes our mitochondria to increase its density to match those needs. But the reverse is also true. A sedentary lifestyle can signal to the body to create less energy, and actually inhibit our body’s natural production of its most vital energy resources.

Here’s a glimpse at what’s going on at a cellular level when it comes to energy. 

1. Mitochondria

You may remember these being referred to as the “powerhouse of the cell,” and it’s true. Without these little “organelles,” we couldn’t turn food or drinks into the energy we need to survive. 

2. The Matrix

The matrix is real, it’s a gel-like material, and it’s inside of every single one of your cells (with mitochondria). This “mitochondrial matrix” is where we release stored energy.  

3. Citric Acid Cycle

This series of very fortunate chemical reactions is used to release some of that stored energy in the matrix. It’s so important, it goes by two names (aka the Krebs Cycle). 

4. Prokaryotic Ancestry

Even our cells have an ancestry, in this case specifically our mitochondria. These leftover bits from the single-cell, simple organisms are the reason why mitochondria can divide and replicate themselves independently of the cells they’re in. This allows the mitochondria to adjust their shape and structure depending on our cell’s metabolic needs.

5. Fission

When mitochondria divide, it’s called fission, and it’s just one of the many ways they maintain our cells’ ability to create energy.

6. Adenosine Triphosphate (ATP)

This molecule IS energy. Whenever you’re tired, you don’t need more caffeine, you need more ATP. Creating it is basically a highly advanced, microscopic game of hot potato. Our cells toss electrons from the carbs, fats, and proteins we consume over to oxygen molecules. Which allows the other essential ATP creation processes to complete. 

7. Nicotinamide adenine dinucleotide (NAD)

This molecule is found in every living cell and helps generate ATP. NAD is an essential part of the process, but also changes in supply depending on our lifestyle habits and needs.

8. Cellular Respiration

This complicated multi-step process uses ATP, the Citric Acid Cycle, and NAD to continually break down sugar from our food and drinks and turn them into the energy we need to stay healthy. 

Energy creation begins and ends with our cells. Sure, daily exercise is great for that midday boost and sometimes we only have time for a caffeine rush. But if we really desire to feel more energetic throughout the day and for the rest of our lives, we shouldn’t settle for a quick fix. We need to pay attention to the parts of our bodies that create that energy and find better ways of giving them the resources they need to function at their best (so we can too). 

We all know exercise is good for us. We remind ourselves of it whenever we’re tempted to sleep in instead of work out or go home after work instead of to the gym. But what’s actually happening to our bodies during exercise? Does it really give us more energy or is that all in our heads? And does carbo-loading actually do anything for my workouts?

We looked behind the scenes at what’s really going on with our muscles when we exercise to address some of these questions and more.

You really can’t control your heart

We have three kinds of muscles: skeletal, cardiac, and smooth. Our brains control our heart muscles and smooth muscles, but only subconsciously.

When we talk about exercising, we’re referring to our skeletal muscles, the ones we can control. And those muscles use different energy sources depending on how long and how intense your workouts are.

But monitoring your heart rate can help

A higher heart rate means more blood is pumping through our bodies. The whole reason our heart rate increases during workouts in the first place is to get more oxygen to our mitochondria (and remove CO2 waste). Monitoring heart rate during exercise can help track our exercise intensity, and whether we’re getting the most out of our workouts.

Plan time to digest

Trying to digest food while working out is hard. Plus, working out actually moves more blood to your muscles and less to your digestive organs. If you’re trying to use certain nutrients to give your workouts a boost, plan ahead by eating two hours before exercise.

Exercise and energy go hand in hand

Every exercise draws and uses energy in different ways. Aerobic workouts such as walking briskly, running, jogging, dancing, swimming, biking, or playing tennis, basketball, soccer, or racquetball, require more energy over a longer time. Your body uses oxygen to “burn” fats and sugars stored in muscle, liver, and fat tissue. It’s a process that takes longer to generate energy, but ultimately provides a long-lasting source of power.

Anaerobic workouts, such as weight lifting or sprinting, require short, intense bursts of energy.  This energy comes straight from the sugars and creatine phosphate stored in muscles themselves.

If you want to give your body the energy it needs, it helps to know where that energy is coming from in the first place.

Weight training doesn’t burn fat

Fats aren’t metabolized during short burst, high-intensity workouts (anaerobic). That said, how much skeletal muscle mass we have is a big factor in how much “resting” energy we use. Which is why a combination of strength training and aerobic exercise is recommended, especially when trying to lose weight.

Aerobic exercises give you a better ROI

With aerobic exercises, you can draw energy from both fats and carbohydrates. And for every sugar molecule you metabolize, you can produce more cellular energy compared to anaerobic exercise.

Carbo-loading is real…sort of

Carbo-loading doesn’t help with high-intensity, short-term anaerobic workouts. That’s because carbo-loading is a process of saving up sugars to use later. By nature, anaerobic workouts are short-term, and you simply never get to tap into those reserves.

But regardless of how you feel about this trend, aerobic activities still rely on carbohydrates as fuel. So, carbo-loading before long endurance activities is helpful.

This molecule can help

Transforming this energy from food into something we can use only works if we have certain vital resources, like NAD (nicotinamide adenine dinucleotide). Without NAD, our bodies wouldn’t be able to make ATP, and ATP is cellular energy. When it comes to generating energy, NAD is just as important as the foods we eat.

But our supply of NAD can also change depending on our needs and lifestyle habits. So, in addition to monitoring our heart rate, and knowing where our muscles draw energy from during different kinds of workouts, it’s also worth figuring out a way to increase NAD. Whether you’re an occasional yogi or an every day runner, these elements can work together to help us maximize every kind of exercise.

How fast you run doesn’t depend on your muscles

Okay it does, but not as much as you’d think. No matter how much lifting or training we do, the main energy source our muscles need to move is a molecule called ATP. How quickly we can regenerate ATP determines how much energy we can use and how long we have before it runs out. This ultimately limits how long we can run at a particular pace.

You never “make” energy

Energy can’t be created or destroyed (first law of thermodynamics). There’s a constant amount of energy in the universe. All we’re doing when we work out is transforming one kind of energy (food) into another kind (cellular) which then powers everything we do, including moving our muscles.

So much of the health advice we hear has to do with staying hydrated. But it can be hard to stay motivated ounce after ounce, or to even know which advice is real or not. Don't worry, we've got you covered.

We are water

Water molecules account for 70% or more of a total cell mass, making it the most abundant molecule in our bodies. The percentage of water in the body peaks around 75% in infants and goes as low as 45% in older populations.

One big reason for this is simply that oil and water don’t mix. Meaning fat tissues will naturally contain less water than other tissues (like muscles). And because we also tend to lose lean muscle mass as we age, it makes sense that we would also lose the supplies of water those tissues contain.

Electrolyte is just a fancy word for salt

The term “electrolytes” gets thrown around a lot when we’re talking about hydration and guess what—it’s basically a fancy scientific word for salts.

When we say salts, we’re talking about things like potassium, magnesium, sodium, and chloride. And yes, that’s the same sodium and chloride that make up table salt.

Sometimes your cells get salty

Salt has a bad reputation and for good reason. The amount of salt in our blood (sodium specifically), is very closely tied to blood pressure. Which is why people suffering from hypertension are often advised to eat low-sodium diets. But the levels of salt in our blood also serve a necessary purpose.

Salts help our cells and tissues stay the right size through a process called “osmosis,” which you may remember from high school biology. Water tends to enter cells with more “stuff” in them (salts, proteins, other molecules) compared to their surroundings. That balance between salt and water controls the size of our cells. Meaning they can actually swell if they gain too much water or shrink if they lose too much.

Kidneys do the heavy lifting

At any given time, 20–25% of your blood is going through your kidneys. Our kidneys are what maintain our internal balance between water and salts (electrolytes). This proper balance is essential for pretty much all of our bodily functions. Thankfully, we have a lot of systems in place to ensure this balance stays where it needs to be.

Staying hydrated requires a lot of energy (and NAD)

Your kidneys work very hard to actively control what stays in your blood or leaves your body. This process requires a ton of cellular energy. Your cells wouldn’t be able to generate any of that energy without NAD (nicotinamide adenine dinucleotide).

Caffeinated beverages don’t actually dehydrate you

One of the many myths floating around about caffeine is that it dehydrates you. This assumption is based off the fact that caffeine is a diuretic, meaning it enhances urinary output and can help eliminate excess water and salts from the body. Although caffeine is a diuretic, if you’re drinking it in a beverage it offsets the water loss.

If you’re thirsty, you’re already dehydrated

There’s a reason why this phrase is so well-known. Losing only 1–2% of your body’s total water can cause a mild but marked decline in cognitive performance. This is also the same time your body starts to trigger the sensation of thirst. Meaning that by the time you feel thirsty, you’re already mildly dehydrated.

Coconut water might be better for you than plain water

One study tested sodium-enriched fresh young coconut water, fresh young coconut water that wasn’t enriched with sodium, a sports drink, and plain water to see which did best at rehydrating. The answer? Sports drink and sodium-enriched coconut water rehydrated better than plain water.

Drinking water can’t really prevent headaches

You may have noticed a headache when you get dehydrated, but there is surprisingly very little research that can explain this phenomenon. One study done by a group of curious medical students showed evidence that dehydration headaches are real.

The 8 x 8 rule may not work for you

Most health professionals recommend drinking eight glasses of eight ounces of water every day. But the reality is (as usual) more complex than that. How much water we need to stay hydrated depends on a host of factors like our body type, environment, and level of physical activity. The 8 x 8 rule is just a guideline.

Salt cravings are real

Dehydration can also lead to a sodium imbalance, which can create a sensation known as “salt appetite.” Your body literally craves salt because you need more of it.

Eat food when you’re bored with drinking water

This may seem obvious but just like humans are almost 50–60% water, our foods also contain a high percentage of this life-giving molecule. So, eating foods with a higher water content can help keep us hydrated.

We also create water when metabolizing fats and sugars (another process that requires NAD). Some animals hardly ever drink because they make all the water they need from food. We’re not saying that works all the time, but if you’re bored with drinking water, there are some other tastier options.