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Boost Energy at 40


Article at a Glance

  • Physiological changes in 40-year-old males contribute to a steady fall in energy.
  • Positive adjustments during midlife are crucial for an energetic and healthy aging body.
  • Energy can be boosted through 5 ways: maintaining telomeres, increasing testosterone levels, enhancing cognition, improving mitochondrial function, and balancing gut microbiome.

Everyone is interested in ways to improve their energy levels, especially as they age. Eating a balanced diet, exercising, quitting smoking, and quitting drinking are commonly known ways to boost energy.

It’s important, though, to understand the physiology of the body and the age- and gender-specific changes so that we can really comprehend why certain strategies offer improved health.

Here we look at 40-year-old men, their bodily changes involved in declining energy, and some ways to counteract these changes. At this age, there are various changes that combine to contribute to overall fatigue, including:

  • Shortening telomeres
  • Decreasing testosterone levels
  • Cognitive decline
  • Changes in gut microbiome
  • Reduced mitochondrial efficiency

Let’s explore these in more detail and identify some scientifically backed ways to control them and replenish your energy. Keep in mind that this is just a list of a few things that you can do to boost energy at 40, but there are far more depending on your current health and the intended effects that you want to produce.

1. Maintain Telomeres

Biological aging is defined by telomeres, which are caps at the ends of chromosomes protecting the integrity of our information-carrying DNA, known to be involved in reversing aging.

With every cell division, a chunk of chromosomes is lost, shortening telomeres over time. Cells are constantly dividing to create new cells and to compensate for damage or cell death.

The number of times cells divide in a set period of time depends on which part of the body they are part of.

For example, as you finish reading this article, assuming it takes 5 minutes, you will have lost an average of 80,000 skin cells. These all have to be replaced, through cell division, with new, but “older,” cells of shorter telomeres.

As telomeres shorten, cells approach their division limit, called the Hayflick limit, defined by factors like cell type. When telomeres run out, cells of that lineage reach senescence, meaning they can no longer divide [R].

Though cellular senescence is protective, it ironically also contributes to the development of age-related diseases, organ deterioration, and overall fatigue because there are fewer cells over time to perform the same tasks.

Maintaining telomere lengths, therefore, offers longevity, healthy aging, and an energized body. One easy, cost-effective, and research-backed way to maintain telomeres is through physical exercise.

An important study in Germany done in 2010, found that telomere shortening was reduced by a staggering 75% in middle-aged marathon runners [R]. Though it may sound obvious to say that exercise would help healthy aging, it is worth noting the degree to which this is the case. In fact, the more exercise one does, the longer their telomeres are.

So, although not known by the average population, telomere length maintenance is one of the reasons exercise is highly recommended. You’re probably curious to know how your telomere lengths compare to other men your age. If so, you can test your telomere length via an at-home kit that can be purchased through TeloYears, a genetic age testing company [R].

2. Increase Testosterone Levels

Testosterone is the masculinity hormone and its production is regulated by the hypothalamic-pituitary-testicular axis (HPA-axis). Along with several other very important functions, it plays a role in energy levels and mood. Thus, a deficiency contributes to the development of fatigue.

There’s a wide range of values considered to be normal testosterone levels in the blood- ranging from 300-1000 ng/dL. Factors like genetics, race, and body composition influence the norm, as does aging.

There is thought to be an age-dependent drop in testosterone levels in men, due to testicular dysfunction or aging, thought to start between ages 30-40, and declining at a rate of 1.6% every year [R].

In middle-aged men, body composition plays a significant role in defining ideal testosterone levels [R]. Men with less fat and more lean muscle have higher levels of testosterone.

Furthermore, with age, testosterone is increasingly converted into estradiol, a form of estrogen. Interestingly, this conversion happens in fat tissue [R]. So, when there is less fat, there is less conversion, and therefore loss, of testosterone.

Decreasing fat, and increasing lean muscle hence contribute to the increase in testosterone levels [R].

Strength training is a highly effective method for lean muscle development because it not only builds muscle but melts away fat tissue as well. When strength training is combined with supplements, the results are outstanding. There are many readily available supplements that advertise their positive effects on muscle gain. However, most of them have unsubstantiated claims, with creatine being one of the exceptions.

Creatine is a protein that is taken up by skeletal muscle, where it improves high-intensity exercise capacity, allowing one to train with heavier weights during resistance training [R]. Studies found that creatine-supplemented groups had a significantly greater increase in muscle mass compared to the placebo group [R].

So creatine helps increase muscle mass, which is known to increase testosterone levels, implying the effects of creatine are indirect. However, there are studies showing creatine may increase the conversion of testosterone into dihydrotestosterone, a more active form of testosterone [R]. The exact mechanism of action is yet to be understood, but it shows that creatine may also have a direct effect on testosterone.

Keep in mind that these positive effects of creatine are only proven in combination with strength training.

Increasing testosterone can also be done through medical interventions, and the popularity of these methods is increasing with more people seeking them out, more doctors offering the, and more clinics popping up across the country. Taking testosterone, dehydroepiandrosterone (DHEA), pregnenolone, and HCG are actually used quite commonly for increasing testosterone, and if under the guidance of a physician can be helpful, but there is still more research to be done around safety considerations. You can find clinics close to you that offer these services in our directory.

3. Boost Cognition

Cognitive functioning (reasoning, memory, and comprehension skills) declines with age, starting at midlife [R], contributing to an energy drop. Brain volume and weight is known to decline at a rate of 5% per decade, starting at 40. So this is the time that can define the progression of potential diseases in later decades [R].

Boost Energy at 40 cognition

One of the early changes associated with a cognitive decline lies in the dopamine system. Dopamine is a neurotransmitter, or signaling compound, in the brain, providing us with the drive and focus to be productive. A lack of dopamine is therefore associated with a fatigued brain and contributes to the development of brain diseases, like Alzheimer’s.

An effective way to increase dopamine is, very interestingly, meditation. A study done in 2002 studied people in a meditative state and found their brain levels of dopamine increased by 65% [R].

Another way to improve cognitive function is through messaging. It has been shown to decrease levels of cortisol, the stress hormone, which in high levels is associated with poor cognition [R]. In addition, massage therapy also increases levels of dopamine by 31% and serotonin (another positive-mood-related brain compound) by 28% [R].

There are also numerous nootropic and adaptogenic supplements that are effective, which are described in greater detail in deeper dives you can find on

4. Improve Gut Microbiome

The gut is probably the most underrated system in our bodies. It functions as our second brain, helping us absorb energy from our diet and prevent disease. It even communicates directly with the brain, working together to maintain well-being [R].

Our gut doesn’t function independently. Its lining is inhabited by millions of bacteria, known as our gut microbiome, which mediates the functions of the gut and is essential for energy absorption from our diet.

Microbiome populations in our gut are very balanced. Sometimes, there is an imbalance, known as gut dysbiosis, which causes temporary mild stomach aches. In many cases, this imbalance can be corrected by our bodies without treatment.

However, dysbiosis is also an age-related effect, becoming apparent at midlife [R]. So, the ’40s are a perfect time to consider treatment methods to maintain gut balance.

Probiotics are an excellent dietary supplement known to offer gut microbiome balance. They mostly consist of the lactobacilli and bifidobacterial strains, proven to aid in gut functioning [R].

Another effective way to improve gut functioning is through calorie restriction (CR). CR is a dietary regimen that reduces calories without causing malnutrition. Since the 1930s, CR has been known as “the only effective environmental intervention that is known to extend lifespan in many organisms” [R].

Among many of the health benefits provided by CR is the alteration to more favorable and balanced gut microbiota, increasing lactobacilli and bifidobacteria strains, and decreasing “bad” bacteria strain Helicobacter [R].

Boost Energy at 40 mitochondrial function

5. Enhance Mitochondrial Function

We can’t discuss energy levels without including mitochondria, the energy powerhouses of all our cells. Without mitochondria, our cells are unable to create adenosine triphosphate (ATP), which is the “energy currency” of our bodies.

Like with many other factors, a drop in mitochondrial function is associated with normal aging, characterized by a drop in ATP production.

Fortunately, there are ways to produce more mitochondria and enhance its function.

Mitochondrial biogenesis can be enhanced through consistent, short sessions of extreme cold exposure, or cryotherapy. This is because cold exposure tricks the body into thinking it has to enter a state of survival, wherein it needs more ATP available and so upregulates its mitochondrial production [R].

In fact, cold exposure has been shown to improve many of the features that come with aging, including cognitive function, and is becoming increasingly popular, especially amongst elite athletes, as it reduces recovery time.

Another method to increase mitochondria functioning is through the increase of levels of nicotinamide adenine dinucleotide (NAD).

NAD has been labeled the “fountain of youth” by Harvard Professor David Sinclair, who was able to reverse DNA damage and turn elderly mice into energetic young ones using this compound [R].

NAD is a coenzyme, naturally produced by the body and plays a crucial role in the mitochondrial metabolic pathways. It has gained a lot of popularity recently, especially in the world of anti-aging as it is involved in reversing DNA damage that comes with age, and has been shown to increase energy levels.

In fact, the anti-aging effects of NAD have been compared to those of calorie restriction. Not surprisingly, it’s also one of those compounds that decrease with age [R].

Recent studies to increase NAD involve administration of its precursors, nicotinamide riboside (NR) or nicotinamide dinucleotide (NMN).

NR is converted into NAD when inside the body, and has been proven by several studies to be a safe supplement and its effects are shockingly positive. A 2018 study showed that the administration of NR increases NAD levels by ~ 60% in middle-aged and older adults [R]. So this is an extremely promising treatment that is undergoing further analysis.

NMN has similarly promising results, but not yet in humans. A study in 2017 on mice found that NMN administration significantly increased NAD levels [R]. There are currently at least two clinical trials on humans underway.

It’s not yet known which NAD booster is best and in what dosages, so keep an eye out for new research in this field- you can expect to see a lot of it.


Your 40’s are the perfect decade make a change to your body. These ways to boost energy at 40 are not mere superficial solutions, but rather ones that touch the underlying causes of your decline.

Positive, smart changes in this phase of life not only help with boosting your energy but also help with an overall healthy mind and body.

If you want to make a real difference and age in a healthy manner, consult professionals for your specific needs. You can start by looking at our directory of aging clinics for guidance.

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. Information is provided for educational purposes. You should consult your doctor before acting on any content on this website.

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