When people hear “low energy,” they often picture an afternoon slump or needing another cup of coffee. But the effects can reach further into daily life: cutting a shopping trip short, skipping a walk, or feeling like ordinary chores take more out of you than they used to.
Over time, these changes can affect your confidence, independence, and willingness to do the things you enjoy.
It’s easy to say, “I’m just getting older.” But that explanation can keep us from asking a more useful question: What might be contributing—and what can we do about it?
Your body’s energy systems offer one piece of that bigger picture.
Where Your Body’s Energy Comes From
Inside most of your cells are tiny structures called mitochondria. They use oxygen and nutrients from food to help produce ATP, a molecule that supplies energy for cellular work.
Think of food as the raw material and ATP as a usable form of energy your cells can put to work. Muscles, nerves, and organs depend on that ongoing supply. Cells with greater energy demands generally contain more mitochondria.
Your body uses energy all day—not just when you’re physically active. Even while you sit quietly, your cells are working to keep you functioning.
In Mitochondria and the Future of Medicine, Lee Know, ND, explores the connections between mitochondrial function, aging, and health. One idea he discusses is that accumulated mitochondrial damage may reduce cells’ ability to supply energy, potentially contributing to declining tissue function over time. This is part of a theory of aging, rather than a complete explanation for why we age.
Mitochondria also do more than produce ATP. They participate in cell signaling and help regulate the removal of damaged cells. That broader role is one reason researchers are studying their connections with many different health conditions.
How Changes Can Show Up in Everyday Life
You don’t need to understand every detail of cellular biology to recognize when daily life starts feeling harder.
Everyday activities take more effort. Stairs, errands, or an afternoon in the garden may leave you needing longer breaks. Changes in conditioning, sleep, nutrition, and health can all affect energy and endurance.
Strength and balance feel less reliable. Getting up from a chair or carrying groceries may become more challenging as strength and activity decline. Although muscles need energy to work, balance also depends on vision, sensation, coordination, and other systems. Feeling unsteady does not automatically mean there is a problem with your mitochondria.
Thinking feels slower or less clear. Trouble concentrating can make ordinary tasks feel more demanding. Brain fog has many possible causes, including poor sleep, stress, medications, and medical conditions.
Managing weight feels more difficult. When you feel drained, staying active, preparing meals, and maintaining routines can become harder. Weight and metabolic health involve many interacting factors; they cannot be reduced to a single problem with cellular energy.
These changes are reasons to pay attention—not a checklist for diagnosing mitochondrial dysfunction.
Aging Is Part of the Picture, but So Is Daily Life
Researchers have observed that mitochondrial function often decreases with age. However, separating the effects of aging from the effects of becoming less active can be difficult. Researchers also continue to investigate whether mitochondrial changes cause certain diseases, result from them, or work in both directions.
That uncertainty matters. It keeps us from treating every symptom as an “energy problem” while still recognizing that cellular health deserves attention.
For many people, a practical starting point includes:
Regular movement suited to your abilities. Walking, gardening, and an appropriate strength program can help you stay active.
Consistent, restorative sleep. Give your body time to recover and discuss ongoing sleep difficulties with your healthcare professional.
Nutritious meals. Support your body with regular, balanced eating rather than relying on caffeine to get through the day.
Attention to persistent fatigue. If low energy is new, worsening, or not improving, seek an evaluation. Conditions such as anemia or thyroid problems may need specific treatment.
You don’t have to overhaul your life overnight. You can start by noticing what has changed and getting help choosing a manageable next step.
Join Me for Our Energy Workshop
I’ll be discussing how the body makes and uses energy—and how that connects with whole-body health—at our:
Energy Workshop
December 3, 2026 at 11:00 AM
With Dr. Rob Sumner DPT, ATC, CSCS
This workshop is especially for people who feel they have less energy than they used to, are struggling with weight or metabolic health, or want to understand why everyday activities seem to take more out of them.
Some of the ideas I’ll share are informed by Mitochondria and the Future of Medicine by Lee Know, ND. We’ll explore the bigger picture and discuss practical ways to support energy and health.
The goal is to help you understand your body so you can keep participating in the life you enjoy.
Contact us to learn more about the workshop.
Sumner Specialized Physical Therapy
📍 212 W Birch Ave Colville, Wa
📞 (509)684-5621
The author, Rob Sumner, is a Doctor of Physical Therapy, Athletic Trainer, Certified Strength & Conditioning Specialist. He is the owner of Specialized Strength Fitness, Specialized Massage and Specialized Physical Therapy in Colville. He's happy to answer any questions about this article, wellness, fitness, or your health overall by phone at (509) 684-5621 or by email at Rob@SumnerPT.com
