January 10, 2024

The Science Behind How Your Body Ages in Your 30s, 40s, 50s, and Beyond

photo of Allie Baker

Written By

Allie Baker

photo of Kerri Masutto, MD

Medically Reviewed By

Kerri Masutto, MD


photo of Vinita Tandon, MD

Medically Reviewed By

Vinita Tandon, MD

Lifeforce Medical Director

The Science Behind How Your Body Ages in Your 30s, 40s, 50s, and Beyond

You’ve probably heard the saying, “the only constant in life is change” — and turns out, that’s true for everything down to the cells in our bodies. In fact, the aging process actually begins as early as 30. 

According to Dr. Vinita Tandon, Lifeforce’s Medical Director and a board certified endocrinologist, “Everything including the liver, kidney, and heart peaks around 30 and then starts to decline. For most of your organs, you don’t notice it because of their reserve ability, but as you get older, your cells and organs begin to lose function.” 

Here’s how it works: Cells can only divide a limited number of times, which is determined by genetics. Structures within cells, called telomeres, shorten every time a cell divides. Eventually cells can no longer divide, which is called cell senescence. According to the National Institute on Aging, senescent cells release chemicals that may trigger inflammation, gradually leading to decreased immunity, mobility, cognitive function, and more. 

Some of these performance changes are inevitable, but the good news is: “You have a lot of control over how you age,” says Dr. Tandon. “If you can try to mitigate health problems by making good lifestyle choices, it can go a long way toward optimizing your healthspan.” 

Research shows that genetics account for only 20 to 30 percent of a person’s chance of living to 85 years old. Lifestyle factors, including diet and exercise, play a key role in determining not only life span, but more importantly, healthspan — your quality of life as you age. We asked Dr. Tandon to help us break down the science behind how our bodies change in each decade, and what you can do to feel your best. 


In Your 30s

Energy and Endurance 

That dip in energy levels, stamina, and endurance — it’s not just you. Research shows that endurance peaks between ages 25 and 30 and declines approximately 10% per decade after that. So don’t be surprised if you wake up feeling unrestored in the morning or experience an energy crash in the afternoon, Dr. Tandon says.

What you can do: Sleep is so underappreciated, but so important,” Dr. Tandon says. “It can make or break your day.” The American Academy of Sleep Medicine recommends that adults get at least seven hours of sleep to perform at their best, but research shows that more than one third of Americans aren’t hitting the mark. Try powering down your devices at least an hour before bed to avoid sleep disruption from blue light, Dr. Tandon suggests. Lifeforce Peak Rest can also help optimize your circadian rhythm for deep, uninterrupted sleep.


Give me one momen— wait, what was I doing? Cognitively, you may have a harder time focusing at work and get more easily distracted. Some of it’s the culture of scrolling on social media and other distractions, but part of it is the natural aging process. Brain cells begin to die off in our 30s and we don’t have as much new growth as we did when we were younger, Dr. Tandon explains. Conveying information between brain cells also begins to take longer. 

What you can do: Now is a great time to start doing word games, brain exercises, and crossword puzzles, Dr. Tandon suggests. Research backs this up, finding that games can help boost cognitive function. Also, try to be focused and present with one task at a time — putting your phone on ‘Do Not Disturb’ mode can help, too. And for extra cognitive support, Peak Rise enhances how efficiently neurotransmitters signal to key neurons in the brain, boosting your concentration and memory. 


For men, testosterone levels peak in the late 20s to early 30s and then begin to drop 1 to 2% every year, according to Dr. Tandon. With that, often comes declines in libido, stamina, endurance, and lean muscle mass (more on that here). Meanwhile, women may begin to experience hormonal changes in their menstrual cycle. And PMS symptoms may worsen due to more exaggerated hormone fluctuations in the week leading up to their period, including bloating, irritability, and poor sleep quality. Periods can become more irregular, as well, Dr. Tandon notes. 

What you can do: Guys, it’s time to get serious about factors like weight, sleep, and stress, which all affect testosterone levels. (Not sure your testosterone levels? Find out with the Lifeforce Diagnostic.) Dr. Tandon suggests maintaining a healthy weight through exercise and clean eating, getting six to eight hours of sleep, and focusing on ways to reduce stress like meditation. Another useful tool: “DHEA is a precursor to testosterone and improving this can help improve testosterone levels,” says Dr. Tandon. 

For women, make sure to take time for yourself and get plenty of rest around your period. Staying hydrated and minimizing salt intake will also help mitigate PMS symptoms. “Some women may benefit from hormonal support during their PMS week to improve their symptoms, as well,” says Dr. Tandon.  




In Your 4Os

Body Composition 

Eating well and hitting the gym? You may still start to notice less lean muscle mass and increased fat mass. According to research, in both men and women this can be caused by a decrease in the rate at which lipids (fat) are removed. For women in particular, this weight is more likely to be around the midsection because lower levels of estrogen affect how fat is distributed. And you may not feel as strong, energetic, or lean — even if you’re doing the same workouts you did in your 20s and 30s.

What you can do: If you’re not already strength training regularly, now is the time to start. Weight training helps build lean muscle and promotes bone health. Dr. Tandon also suggests focusing on your protein intake. Protein supports a healthy metabolism and fuels your muscles so you can recover post-workout and form lean muscle. 


“At this age, women typically enter perimenopause and start to experience more intense hormone fluctuations,” Dr. Tandon says. This can manifest in irregular cycles, heavy bleeding, more mood swings, and occasional hot flashes (especially on hot days or if you drink alcohol or caffeine), which can result in poor sleep, low energy, and fogginess the next day. Meanwhile, men will feel a much more significant drop in their testosterone, leading to less muscle tone, stamina, energy, and endurance. Lower libido and less interest in intimacy are also common in both men and women after hitting the big 4-0. 

What you can do: Consult a physician to see if you’re ready for hormone replacement therapy, Dr. Tandon suggests. For both men and women, the Lifeforce Diagnostic is a great place to start. It will give you a clear picture of your hormone levels, then an expert Lifeforce clinician will interpret your results and put together your personalized performance plan. 


Antioxidants protect the body from oxidative stress and free radicals, which can lead to inflammation. “Think of antioxidants like a vacuum cleaner,” Dr. Tandon says. “They clean up all the toxins and free radicals.” As you age, your body naturally makes less antioxidants, but this is when you need them most. In your 40s, you’ll experience more cell death, free radicals, and inflammation. 

What you can do: Increase your intake of antioxidant-packed, anti-inflammatory foods like berries, leafy greens, tomatoes, avocados, and green tea. Dr. Tandon also suggests nutraceuticals to help your cells heal and your body recover from inflammation more effectively. Lifeforce’s Peak Healthspan and Peak NMN work together to promote cell longevity and healthy aging mechanisms. 


In Your 50s

Heart Health 

Now’s the time to really monitor and protect your heart. In your 50s, you may see a rise in cholesterol levels, blood pressure, and blood sugar. For women, these issues can be exacerbated by menopause. When you go through menopause, your levels of estrogen — one of the biggest heart protectors — drop dramatically. 

What you can do: Test your total cholesterol, HDL, LDL, triglycerides, and other markers of heart health with the Lifeforce Diagnostic. “Your diet is also key for protecting your heart,” Dr. Tandon says. She suggests cutting back on processed, sugary, and high-sodium foods and having plenty of fiber-filled fruits and veggies. Omega-3 fatty acids are also proven heart protectors. Lifeforce Omega is an effective tool to optimize your HDL, LDL, and triglyceride levels. 


The average American woman enters menopause at age 51. “For many women, this can wreak havoc on your body,” says Dr. Tandon, resulting in weight gain around the middle, reduced muscle mass, hot flashes, flushing, decline in bone mass, low libido, and issues with sexual wellness. Women will also feel declines in cognition, focus, mood, and quality of sleep. “This can majorly impact quality of life at a time when women are juggling a lot,” says Dr. Tandon. For men, testosterone lowers even more in the 50s, leading to declines in libido, sexual function, mood, confidence, and body image. 

What you can do: A lot! Now is a great time to measure (or re-assess) your baseline with the Lifeforce Diagnostic and work with a trusted clinician to get everything back in balance. Dr. Tandon also suggests Lifeforce DHEA for both men and women to help you maintain optimum hormone levels for sexual health, weight loss, heart health, and more. 

Mood and Motivation 

If you find yourself more anxious, tearful, or easily triggered by things that never used to bother you, this may be a side effect of hormone fluctuations. When hormone levels drop, it affects neurotransmitters in the brain related to emotional health. Men and women also both notice feeling less driven, engaged, and motivated, according to Dr. Tandon. Psychologists call this anhedonia, and research shows that as many as one in three older adults experience it.

What you can do: Hormone therapy goes a long way to boosting mood and enhancing emotional wellness. Learn more about Lifeforce’s hormone optimization here. And for help coping with those extra bouts of stress: “Lifeforce Magnesium is an excellent supplement to help with stress modulation and relaxation,” says Dr. Tandon.  


In Your 60s

Bone Health

You’ve heard that bone mass declines with age and decreasing hormone levels, and here’s why it matters: In your 60s, it can culminate in more achy joints, and you may even develop arthritis. Research also shows that weakened bones can lead to fractures for one in two women and one in five men after age 50. 

What you can do: Exercise is essential for maintaining bone health. Dr. Tandon suggests mixing up your fitness routine — do light resistance training to build muscle mass, functional exercises to target mobility and balance, and light cardio for heart health. Getting plenty of calcium and vitamin D is also key. Lifeforce Vitamin D+K is clinically proven to raise vitamin D levels three times faster and more effectively than other types.


Notice yourself feeling tired earlier, but not being able to stay asleep through the night? In your 60s, you may experience a change in your circadian rhythm, which determines your sleep/wake cycle.

What you can do: Peak Rest helps optimize your circadian rhythm for a higher quality, deeper sleep. And if you do wake up in the middle of the night, avoid looking at your phone or any other devices, advises Dr. Tandon. The blue light will signal your brain to wake up even more. Instead, soothe yourself back to sleep with meditation, white noise, or calming sounds of nature.


Your body produces even fewer antioxidants and your immune system wanes during this decade, making you more susceptible to illness, Dr. Tandon says. Research also shows that the immune system functions less optimally as we age. 

What you can do: A healthy antioxidant-packed diet, lots of water, and sleep are all more important than ever to optimize your immune system. Dr. Tandon also suggests nutraceuticals like Peak Defense to give your immune system a boost. With 23 bioactive ingredients, it helps provide support against environmental, seasonal, and year-round immunity stressors. 

One thing that’s true at every age: It’s never too early to be proactive about your wellness. “You can optimize your health along the whole journey,” Dr. Tandon says. “As you get older, it takes a little more effort, but it’s worth it!” 


Commonly asked questions about aging at every decade

How significant is the role of genetics versus lifestyle choices in the aging process?

According to Dr. Vinita Tandon, genetics account for only 20 to 30 percent of a person's likelihood of living to 85 years old, suggesting that lifestyle factors such as diet, exercise, sleep, and stress management play a more substantial role in determining not only lifespan but, crucially, healthspan. This emphasizes the power individuals have in influencing their aging process through healthy lifestyle choices, underscoring the importance of adopting habits that support longevity and quality of life.

What specific lifestyle changes can mitigate the decline in muscle mass and function known as sarcopenia?

Can hormone fluctuations in perimenopause and menopause significantly affect women's health, and how can they be managed?

This article was medically reviewed by: 

  • Kerri Masutto, MD, ABIM Board Certified in Internal Medicine, Institute for Functional Medicine Certified Practitioner 

  • Vinita Tandon, MD, ABIM Board Certified in Endocrinology and Metabolism

Originally published on February 21, 2022. Updated on February 27, 2023.

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