LEPIZIG — Sometimes, it feels like certain people have more than 24 hours in a day. There are bosses who work from dawn till dusk, spend their weekends climbing glaciers, and squeeze in marathon training during lunch breaks. Parents who juggle three kids, a full-time job, and housework, while also learning the oboe and playing badminton in a local league.
Meanwhile, others barely muster the energy to reach for the remote after work.
Where do those high-energy people find it? And, more importantly, is it possible to know their formula?
Energy is a tricky thing to define. It’s not something you can see or measure in a simple way.
In scientific terms, it’s the ability of a system to perform labor. Even just staying alive is an energy-intensive process: up to 75% of the body’s available energy is used to keep vital functions running. That makes it even more surprising how much some people manage to squeeze out of the remaining 25%.
And it’s not just about will power — people actually differ in how efficiently their bodies absorb and process energy, and how quickly they tire (Plos One: Jiang et al., 2018, PDF). But that doesn’t mean if you’re a couch potato now, you’re doomed to stay one forever. There are factors that influence energy levels, and some of them are completely within your control.
Mitochondria are energy factories
It’s not called fueling your body for nothing: food is a major energy source. But before the body can use that energy, it has to be converted. That process happens inside the mitochondria, often referred to as the powerhouses of the cells. These tiny structures extract triglycerides and creatine phosphate from food and transform them into adenosine triphosphate (ATP), the body’s go-to energy currency. Every day, we burn through an amount of ATP roughly equal to our body weight just to keep things running.
To keep those energy reserves stocked, the body needs a mix of fats, carbohydrates, and proteins — especially proteins, since they’re the building blocks of mitochondria. Foods like nuts, tofu, and eggs help support cell regeneration. Sugar, on the other hand, provides a quick jolt of energy for muscles and the brain, but the rush from a chocolate bar fades fast. Low-sugar, slow-digesting foods help keep energy levels stable for longer.
Regular training doesn’t just improve the mitochondria’s efficiency: it actually increases their numbers.
Some people, however, are naturally better at producing energy than others. “Professional athletes have up to twice as many mitochondria in their muscle cells (meaning more miniature power plants) than someone who doesn’t exercise much,” explains Ingo Froböse of the German Sport University in Cologne. This happens because regular training doesn’t just improve the mitochondria’s efficiency: it actually increases their numbers.
After diet, exercise is the second major factor influencing energy levels. Surprisingly, high-powered executives and other busy people often find time to exercise. “People who do a lot of cognitive work need exercise as a release valve — it helps balance them out both mentally and physically,” says Froböse. Active people tend to have greater energy reserves to tap into, and these are often the ones who seem to glide effortlessly through life.
Sleep matters
If you want to wake up feeling refreshed, recharging your batteries overnight is essential. Yet, we live in an era of “global fatigue.” A 2023 meta-study that reviewed 91 studies across three continents found that one in five adults has experienced chronic exhaustion lasting up to six months.
“It’s not so much a stress problem — it’s a regeneration problem,” says Froböse. Lack of exercise and poor nutrition are key culprits, but sleep deprivation is also a major factor. While we sleep, our immune system gets stronger, and cells and muscles undergo repair.
A 2023 study, Mitochondria Need Their Sleep, found that sleep deprivation disrupts the body’s repair mechanisms, increasing the risk of metabolic disorders and even cancer.
We live in an era of “global fatigue.”
But while diet, exercise, and sleep are critical, they don’t fully explain why some people seem to have boundless energy while others struggle.
The resilience factor
According to psychotherapist and resilience researcher Isabella Helmreich, energy levels are shaped by a combination of genetics and personal experience: what we learn during childhood and adolescence through interactions with others and our environment. Key factors include mental strength, physical health, and a strong network of social relations.
When and why we feel stressed or overwhelmed largely depends on individual resilience. Helmreich, who works at the Leibniz Institute for Resilience Research in Mainz, defines resilience as the ability to maintain mental health and bounce back after setbacks. “It’s what keeps us going long-term,” she explains. While twin studies suggest resilience is 30 to 50% genetic, the rest is learned: mainly through overcoming challenges. Both personality traits, like emotional stability, and external factors, like social support, play a role.
Resilient individuals have a strong support system, can adapt to change, and tend to have a positive outlook (Translational Psychiatry: Veer et al., 2021). They know how to prioritize, set boundaries, manage their resources effectively, and take breaks when needed. Crucially, they also know how to handle stress.
Prolonged stress can even alter mitochondrial function, weakening immune responses.
“Stress can be a huge drain on energy,” says Helmreich. “It affects mental health and can lead to exhaustion.” One reason for this is that stress triggers the release of cortisol, a hormone that puts the body on high alert, making it harder to relax and sleep. A 2022 study of 16,000 Chinese government employees found that those with job stress or financial worries were twice as likely to experience chronic fatigue. Prolonged stress can even alter mitochondrial function, weakening immune responses (Psychosomatic Medicine: Picard & McEwen, 2018).
Learn to be realistic
But appearances can be deceiving. “Many of my patients push themselves to the limit for years, maintaining the illusion of boundless energy until their bodies finally shut down,” warns psychotherapist Mirriam Prieß. To avoid the trap of relentless self-optimization, it’s crucial to “respect your own limits and make the most of what’s realistically possible.”
Helmreich also advises focusing on small, manageable lifestyle changes rather than striving for perfection. Practicing self-care can help boost energy and overall well-being.
And sometimes, a quiet evening on the couch can be just as valuable as a session on the treadmill.
